A microtubule structure that forms during CELL DIVISION. It consists of two SPINDLE POLES, and sets of MICROTUBULES that may include the astral microtubules, the polar microtubules, and the kinetochore microtubules.
A broad category of nuclear proteins that are components of or participate in the formation of the NUCLEAR MATRIX.
A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species.
Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.
The cell center, consisting of a pair of CENTRIOLES surrounded by a cloud of amorphous material called the pericentriolar region. During interphase, the centrosome nucleates microtubule outgrowth. The centrosome duplicates and, during mitosis, separates to form the two poles of the mitotic spindle (MITOTIC SPINDLE APPARATUS).
The orderly segregation of CHROMOSOMES during MEIOSIS or MITOSIS.
A microtubule subunit protein found in large quantities in mammalian brain. It has also been isolated from SPERM FLAGELLUM; CILIA; and other sources. Structurally, the protein is a dimer with a molecular weight of approximately 120,000 and a sedimentation coefficient of 5.8S. It binds to COLCHICINE; VINCRISTINE; and VINBLASTINE.
A type of CELL NUCLEUS division, occurring during maturation of the GERM CELLS. Two successive cell nucleus divisions following a single chromosome duplication (S PHASE) result in daughter cells with half the number of CHROMOSOMES as the parent cells.
Skeletal muscle structures that function as the MECHANORECEPTORS responsible for the stretch or myotactic reflex (REFLEX, STRETCH). They are composed of a bundle of encapsulated SKELETAL MUSCLE FIBERS, i.e., the intrafusal fibers (nuclear bag 1 fibers, nuclear bag 2 fibers, and nuclear chain fibers) innervated by SENSORY NEURONS.
A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)
Proteins that control the CELL DIVISION CYCLE. This family of proteins includes a wide variety of classes, including CYCLIN-DEPENDENT KINASES, mitogen-activated kinases, CYCLINS, and PHOSPHOPROTEIN PHOSPHATASES as well as their putative substrates such as chromatin-associated proteins, CYTOSKELETAL PROTEINS, and TRANSCRIPTION FACTORS.
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The phase of cell nucleus division following METAPHASE, in which the CHROMATIDS separate and migrate to opposite poles of the spindle.
Large multiprotein complexes that bind the centromeres of the chromosomes to the microtubules of the mitotic spindle during metaphase in the cell cycle.
The phase of cell nucleus division following PROMETAPHASE, in which the CHROMOSOMES line up across the equatorial plane of the SPINDLE APPARATUS prior to separation.
A microtubule-associated mechanical adenosine triphosphatase, that uses the energy of ATP hydrolysis to move organelles along microtubules toward the plus end of the microtubule. The protein is found in squid axoplasm, optic lobes, and in bovine brain. Bovine kinesin is a heterotetramer composed of two heavy (120 kDa) and two light (62 kDa) chains. EC 3.6.1.-.
High molecular weight proteins found in the MICROTUBULES of the cytoskeletal system. Under certain conditions they are required for TUBULIN assembly into the microtubules and stabilize the assembled microtubules.
Nocodazole is an antineoplastic agent which exerts its effect by depolymerizing microtubules.
Mad2 is a component of the spindle-assembly checkpoint apparatus. It binds to and inhibits the Cdc20 activator subunit of the anaphase-promoting complex, preventing the onset of anaphase until all chromosomes are properly aligned at the metaphase plate. Mad2 is required for proper microtubule capture at KINETOCHORES.
A family of highly conserved serine-threonine kinases that are involved in the regulation of MITOSIS. They are involved in many aspects of cell division, including centrosome duplication, SPINDLE APPARATUS formation, chromosome alignment, attachment to the spindle, checkpoint activation, and CYTOKINESIS.
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
A family of multisubunit cytoskeletal motor proteins that use the energy of ATP hydrolysis to power a variety of cellular functions. Dyneins fall into two major classes based upon structural and functional criteria.
The final phase of cell nucleus division following ANAPHASE, in which two daughter nuclei are formed, the CYTOPLASM completes division, and the CHROMOSOMES lose their distinctness and are transformed into CHROMATIN threads.
The cellular signaling system that halts the progression of cells through MITOSIS or MEIOSIS if a defect that will affect CHROMOSOME SEGREGATION is detected.
The process by which the CYTOPLASM of a cell is divided.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).
A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.
An amorphous region of electron dense material in the cytoplasm from which the MICROTUBULES polymerization is nucleated. The pericentriolar region of the CENTROSOME which surrounds the CENTRIOLES is an example.
Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
Proteins found in the microtubules.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.
Motor neurons which activate the contractile regions of intrafusal SKELETAL MUSCLE FIBERS, thus adjusting the sensitivity of the MUSCLE SPINDLES to stretch. Gamma motor neurons may be "static" or "dynamic" according to which aspect of responsiveness (or which fiber types) they regulate. The alpha and gamma motor neurons are often activated together (alpha gamma coactivation) which allows the spindles to contribute to the control of movement trajectories despite changes in muscle length.
Self-replicating, short, fibrous, rod-shaped organelles. Each centriole is a short cylinder containing nine pairs of peripheral microtubules, arranged so as to form the wall of the cylinder.
The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.
The first phase of cell nucleus division, in which the CHROMOSOMES become visible, the CELL NUCLEUS starts to lose its identity, the SPINDLE APPARATUS appears, and the CENTRIOLES migrate toward opposite poles.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
The phase of cell nucleus division following PROPHASE, when the breakdown of the NUCLEAR ENVELOPE occurs and the MITOTIC SPINDLE APPARATUS enters the nuclear region and attaches to the KINETOCHORES.
An organization of cells into an organ-like structure. Organoids can be generated in culture. They are also found in certain neoplasms.
The clear constricted portion of the chromosome at which the chromatids are joined and by which the chromosome is attached to the spindle during cell division.
Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.
The property of nonisotropic media, such as crystals, whereby a single incident beam of light traverses the medium as two beams, each plane-polarized, the planes being at right angles to each other. (Cline et al., Dictionary of Visual Science, 4th ed)
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
Highly conserved proteins that specifically bind to and activate the anaphase-promoting complex-cyclosome, promoting ubiquitination and proteolysis of cell-cycle-regulatory proteins. Cdc20 is essential for anaphase-promoting complex activity, initiation of anaphase, and cyclin proteolysis during mitosis.
A monomeric GTP-binding protein involved in nucleocytoplasmic transport of proteins into the nucleus and RNA into the cytoplasm. This enzyme was formerly listed as EC 3.6.1.47.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
The interval between two successive CELL DIVISIONS during which the CHROMOSOMES are not individually distinguishable. It is composed of the G phases (G1 PHASE; G0 PHASE; G2 PHASE) and S PHASE (when DNA replication occurs).
Proteins obtained from various species of Xenopus. Included here are proteins from the African clawed frog (XENOPUS LAEVIS). Many of these proteins have been the subject of scientific investigations in the area of MORPHOGENESIS and development.

Drosophila oogenesis: versatile spn doctors. (1/4092)

Recent work on Drosophila oogenesis has uncovered connections between cell-cycle checkpoints and pattern formation. Genes of the spindle class, which encode double-strand break repair enzymes and RNA helicases, affect oocyte polarity and the decision whether to differentiate as an oocyte or a nurse cell.  (+info)

C-myc overexpression and p53 loss cooperate to promote genomic instability. (2/4092)

p53 monitors genomic integrity at the G1 and G2/M cell cycle checkpoints. Cells lacking p53 may show gene amplification as well as the polyploidy or aneuploidy typical of many tumors. The pathways through which this develops, however, are not well defined. We demonstrate here that the combination of p53 inactivation and c-myc overexpression in diploid cells markedly accelerates the spontaneous development of tetraploidy. This is not seen with either N-myc or L-myc. Tetraploidy is accompanied by significantly higher levels of cyclin B and its associated cdc2 kinase activity. Mitotic spindle poisons accelerate the appearance of tetraploidy in cells either lacking functional p53 or overexpressing c-myc whereas the combination is additive. Restoration of p53 function in cells overexpressing c-myc causing rapid apoptosis, indicating that cells yet to become tetraploid have nonetheless suffered irreversible genomic and/or mitotic spindle damage. In the face of normal p53 function, such damage would either be repaired or trigger apoptotis. We propose that loss of p53 and overexpression of c-myc permits the emergence and survival of cells with increasingly severe damage and the eventual development of tetraploidy.  (+info)

Defects in Saccharomyces cerevisiae protein phosphatase type I activate the spindle/kinetochore checkpoint. (3/4092)

A conditional allele of type 1 protein phosphatase (glc7-129) in Saccharomyces cerevisiae causes first cycle arrest in G2/M, characterized by cells with a short spindle and high H1 kinase activity. Point-of-execution experiments indicate Glc7p function is required in G2/M just before anaphase for the completion of mitosis. Loss of the spindle/kinetochore checkpoint in glc7-129 cells abolishes the G2/M cell cycle arrest with a concomitant increase in chromosome loss and reduced viability. These results support a role for Glc7p in regulating kinetochore attachment to the spindle, an event monitored by the spindle/kinetochore checkpoint.  (+info)

The conserved protein kinase Ipl1 regulates microtubule binding to kinetochores in budding yeast. (4/4092)

Chromosome segregation depends on kinetochores, the structures that mediate chromosome attachment to the mitotic spindle. We isolated mutants in IPL1, which encodes a protein kinase, in a screen for budding yeast mutants that have defects in sister chromatid separation and segregation. Cytological tests show that ipl1 mutants can separate sister chromatids but are defective in chromosome segregation. Kinetochores assembled in extracts from ipl1 mutants show altered binding to microtubules. Ipl1p phosphorylates the kinetochore component Ndc10p in vitro and we propose that Ipl1p regulates kinetochore function via Ndc10p phosphorylation. Ipl1p localizes to the mitotic spindle and its levels are regulated during the cell cycle. This pattern of localization and regulation is similar to that of Ipl1p homologs in higher eukaryotes, such as the human aurora2 protein. Because aurora2 has been implicated in oncogenesis, defects in kinetochore function may contribute to genetic instability in human tumors.  (+info)

Abnormal spindle protein, Asp, and the integrity of mitotic centrosomal microtubule organizing centers. (5/4092)

The product of the abnormal spindle (asp) gene was found to be an asymmetrically localized component of the centrosome during mitosis, required to focus the poles of the mitotic spindle in vivo. Removing Asp protein function from Drosophila melanogaster embryo extracts, either by mutation or immunodepletion, resulted in loss of their ability to restore microtubule-organizing center activity to salt-stripped centrosome preparations. This was corrected by addition of purified Asp protein. Thus, Asp appears to hold together the microtubule-nucleating gamma-tubulin ring complexes that organize the mitotic centrosome.  (+info)

Influence of centriole behavior on the first spindle formation in zygotes of the brown alga Fucus distichus (Fucales, Phaeophyceae). (6/4092)

The influence of centrioles, derived from the sperm flagellar basal bodies, and the centrosomal material (MTOCs) on spindle formation in the brown alga Fucus distichus (oogamous) was studied by immunofluorescence microscopy using anti-centrin and anti-beta-tubulin antibodies. In contrast to a bipolar spindle, which is formed after normal fertilization, a multipolar spindle was formed in polyspermic zygote. The number of mitotic poles in polyspermic zygotes was double the number of sperm involved in fertilization. As an anti-centrin staining spot (centrioles) was located at these poles, the multipolar spindles in polyspermic zygotes were produced by the supplementary centrioles. When anucleate egg fragments were fertilized, chromosome condensation and mitosis did not occur in the sperm nucleus. Two anti-centrin staining spots could be detected, microtubules (MTs) radiated from nearby, but the mitotic spindle was never produced. When a single sperm fertilized multinucleate eggs (polygyny), abnormal spindles were also observed. In addition to two mitotic poles containing anti-centrin staining spots, extra mitotic poles without anti-centrin staining spots were also formed, and as a result multipolar spindles were formed. When karyogamy was blocked with colchicine, it became clear that the egg nucleus proceeded independently into mitosis accompanying chromosome condensation. A monoastral spindle could be frequently observed, and in rare cases a barrel-shaped spindle was formed. However, when a sperm nucleus was located near an egg nucleus, the two anti-centrin staining spots shifted to the egg nucleus from the sperm nucleus. In this case, a normal spindle was formed, the egg chromosomes arranged at the equator, and the associated MTs elongated from one pole of the egg spindle toward the sperm chromosomes which were scattered. From these results, it became clear that paternal centrioles derived from the sperm have a crucial role in spindle formation in the brown algae, such as they do during animal fertilization. However, paternal centrioles were not adequate for the functional centrosome during spindle formation. We speculated that centrosomal materials from the egg cytoplasm aggregate around the sperm centrioles and are needed for centrosomal activation.  (+info)

Self assembly of NuMA: multiarm oligomers as structural units of a nuclear lattice. (7/4092)

NuMA is a nuclear matrix protein in interphase and relocates to the spindle poles in mitotis. Different NuMA constructs, in which either N- or C-terminal domains were deleted, and the full-length construct were expressed in Escherichia coli, and the NuMA polypeptides were purified to homogeneity and allowed to assemble in vitro. Electron microscopy showed that NuMA can build multiarm oligomers by interaction of the C-terminal globular domains. Each arm of the oligomer corresponds to a NuMA dimer. Oligomers with up to 10 or 12 arms have been observed for both full-length NuMA and for constructs that still contain the proximal part of the C-terminal tail domain. Other results from this laboratory have shown that transient overexpression of NuMA in HeLa cells induces a nuclear scaffold with a quasi-hexagonal organization that can fill the nuclei. Here we show that computer modelling of the three-dimensional packing of NuMA into such scaffolds can explain the different spacing of the hexagons seen when constructs with different coiled-coil lengths are used. Thus, the 12 arm oligomer, for which we have in vitro evidence, may be the structural unit from which the nuclear scaffold in transfected cells is built.  (+info)

Control of mitotic spindle position by the Saccharomyces cerevisiae formin Bni1p. (8/4092)

Alignment of the mitotic spindle with the axis of cell division is an essential process in Saccharomyces cerevisiae that is mediated by interactions between cytoplasmic microtubules and the cell cortex. We found that a cortical protein, the yeast formin Bni1p, was required for spindle orientation. Two striking abnormalities were observed in bni1Delta cells. First, the initial movement of the spindle pole body (SPB) toward the emerging bud was defective. This phenotype is similar to that previously observed in cells lacking the kinesin Kip3p and, in fact, BNI1 and KIP3 were found to be in the same genetic pathway. Second, abnormal pulling interactions between microtubules and the cortex appeared to cause preanaphase spindles in bni1Delta cells to transit back and forth between the mother and the bud. We therefore propose that Bni1p may localize or alter the function of cortical microtubule-binding sites in the bud. Additionally, we present evidence that other bipolar bud site determinants together with cortical actin are also required for spindle orientation.  (+info)

The spindle apparatus is a microtubule-based structure that plays a crucial role in the process of cell division, specifically during mitosis and meiosis. It consists of three main components:

1. The spindle poles: These are organized structures composed of microtubules and associated proteins that serve as the anchoring points for the spindle fibers. In animal cells, these poles are typically formed by centrosomes, while in plant cells, they form around nucleation sites called microtubule-organizing centers (MTOCs).
2. The spindle fibers: These are dynamic arrays of microtubules that extend between the two spindle poles. They can be categorized into three types: kinetochore fibers, which connect to the kinetochores on chromosomes; astral fibers, which radiate from the spindle poles and help position the spindle within the cell; and interpolar fibers, which lie between the two spindle poles and contribute to their separation during anaphase.
3. Regulatory proteins: Various motor proteins, such as dynein and kinesin, as well as non-motor proteins like tubulin and septins, are involved in the assembly, maintenance, and dynamics of the spindle apparatus. These proteins help to generate forces that move chromosomes, position the spindle, and ultimately segregate genetic material between two daughter cells during cell division.

The spindle apparatus is essential for ensuring accurate chromosome separation and maintaining genomic stability during cell division. Dysfunction of the spindle apparatus can lead to various abnormalities, including aneuploidy (abnormal number of chromosomes) and chromosomal instability, which have been implicated in several diseases, such as cancer and developmental disorders.

Nuclear matrix-associated proteins (NMAPs) are a group of structural and functional proteins that are associated with the nuclear matrix, a network of fibers within the nucleus of a eukaryotic cell. The nuclear matrix provides support to the nuclear envelope and plays a role in DNA replication, transcription, and repair. NMAPs can be categorized into several groups based on their functions, including:

1. Scaffold proteins: These proteins provide structural support to the nuclear matrix and help maintain its architecture.
2. Enzymes: These proteins are involved in various biochemical reactions, such as DNA replication and repair, RNA processing, and chromatin remodeling.
3. Transcription factors: These proteins regulate gene expression by binding to specific DNA sequences and interacting with the transcription machinery.
4. Chromatin-associated proteins: These proteins are involved in the organization and regulation of chromatin structure and function.
5. Signal transduction proteins: These proteins transmit signals from the extracellular environment to the nucleus, regulating gene expression and other nuclear functions.

NMAPs have been implicated in various cellular processes, including cell cycle regulation, differentiation, apoptosis, and oncogenesis. Therefore, understanding the structure and function of NMAPs is crucial for elucidating the mechanisms underlying these processes and developing novel therapeutic strategies for various diseases, including cancer.

Mitosis is a type of cell division in which the genetic material of a single cell, called the mother cell, is equally distributed into two identical daughter cells. It's a fundamental process that occurs in multicellular organisms for growth, maintenance, and repair, as well as in unicellular organisms for reproduction.

The process of mitosis can be broken down into several stages: prophase, prometaphase, metaphase, anaphase, and telophase. During prophase, the chromosomes condense and become visible, and the nuclear envelope breaks down. In prometaphase, the nuclear membrane is completely disassembled, and the mitotic spindle fibers attach to the chromosomes at their centromeres.

During metaphase, the chromosomes align at the metaphase plate, an imaginary line equidistant from the two spindle poles. In anaphase, sister chromatids are pulled apart by the spindle fibers and move toward opposite poles of the cell. Finally, in telophase, new nuclear envelopes form around each set of chromosomes, and the chromosomes decondense and become less visible.

Mitosis is followed by cytokinesis, a process that divides the cytoplasm of the mother cell into two separate daughter cells. The result of mitosis and cytokinesis is two genetically identical cells, each with the same number and kind of chromosomes as the original parent cell.

Microtubules are hollow, cylindrical structures composed of tubulin proteins in the cytoskeleton of eukaryotic cells. They play crucial roles in various cellular processes such as maintaining cell shape, intracellular transport, and cell division (mitosis and meiosis). Microtubules are dynamic, undergoing continuous assembly and disassembly, which allows them to rapidly reorganize in response to cellular needs. They also form part of important cellular structures like centrioles, basal bodies, and cilia/flagella.

A centrosome is a microtubule-organizing center found in animal cells. It consists of two barrel-shaped structures called centrioles, which are surrounded by a protein matrix called the pericentriolar material. The centrosome plays a crucial role in organizing the microtubules that form the cell's cytoskeleton and help to shape the cell, as well as in separating the chromosomes during cell division.

During mitosis, the two centrioles of the centrosome separate and move to opposite poles of the cell, where they nucleate the formation of the spindle fibers that pull the chromosomes apart. The centrosome also helps to ensure that the genetic material is equally distributed between the two resulting daughter cells.

It's worth noting that while centrioles are present in many animal cells, they are not always present in all types of cells. For example, plant cells do not have centrioles or centrosomes, and instead rely on other mechanisms to organize their microtubules.

Chromosome segregation is the process that occurs during cell division (mitosis or meiosis) where replicated chromosomes are separated and distributed equally into two daughter cells. Each chromosome consists of two sister chromatids, which are identical copies of genetic material. During chromosome segregation, these sister chromatids are pulled apart by a structure called the mitotic spindle and moved to opposite poles of the cell. This ensures that each new cell receives one copy of each chromosome, preserving the correct number and composition of chromosomes in the organism.

Tubulin is a type of protein that forms microtubules, which are hollow cylindrical structures involved in the cell's cytoskeleton. These structures play important roles in various cellular processes, including maintaining cell shape, cell division, and intracellular transport. There are two main types of tubulin proteins: alpha-tubulin and beta-tubulin. They polymerize to form heterodimers, which then assemble into microtubules. The assembly and disassembly of microtubules are dynamic processes that are regulated by various factors, including GTP hydrolysis, motor proteins, and microtubule-associated proteins (MAPs). Tubulin is an essential component of the eukaryotic cell and has been a target for anti-cancer drugs such as taxanes and vinca alkaloids.

Meiosis is a type of cell division that results in the formation of four daughter cells, each with half the number of chromosomes as the parent cell. It is a key process in sexual reproduction, where it generates gametes or sex cells (sperm and eggs).

The process of meiosis involves one round of DNA replication followed by two successive nuclear divisions, meiosis I and meiosis II. In meiosis I, homologous chromosomes pair, form chiasma and exchange genetic material through crossing over, then separate from each other. In meiosis II, sister chromatids separate, leading to the formation of four haploid cells. This process ensures genetic diversity in offspring by shuffling and recombining genetic information during the formation of gametes.

Muscle spindles are specialized sensory organs found within the muscle belly, which primarily function as proprioceptors, providing information about the length and rate of change in muscle length. They consist of small, encapsulated bundles of intrafusal muscle fibers that are interspersed among the extrafusal muscle fibers (the ones responsible for force generation).

Muscle spindles have two types of sensory receptors called primary and secondary endings. Primary endings are located near the equatorial region of the intrafusal fiber, while secondary endings are situated more distally. These endings detect changes in muscle length and transmit this information to the central nervous system (CNS) through afferent nerve fibers.

The activation of muscle spindles plays a crucial role in reflexive responses, such as the stretch reflex (myotatic reflex), which helps maintain muscle tone and joint stability. Additionally, they contribute to our sense of body position and movement awareness, known as kinesthesia.

The Golgi apparatus, also known as the Golgi complex or simply the Golgi, is a membrane-bound organelle found in the cytoplasm of most eukaryotic cells. It plays a crucial role in the processing, sorting, and packaging of proteins and lipids for transport to their final destinations within the cell or for secretion outside the cell.

The Golgi apparatus consists of a series of flattened, disc-shaped sacs called cisternae, which are stacked together in a parallel arrangement. These stacks are often interconnected by tubular structures called tubules or vesicles. The Golgi apparatus has two main faces: the cis face, which is closest to the endoplasmic reticulum (ER) and receives proteins and lipids directly from the ER; and the trans face, which is responsible for sorting and dispatching these molecules to their final destinations.

The Golgi apparatus performs several essential functions in the cell:

1. Protein processing: After proteins are synthesized in the ER, they are transported to the cis face of the Golgi apparatus, where they undergo various post-translational modifications, such as glycosylation (the addition of sugar molecules) and sulfation. These modifications help determine the protein's final structure, function, and targeting.
2. Lipid modification: The Golgi apparatus also modifies lipids by adding or removing different functional groups, which can influence their properties and localization within the cell.
3. Protein sorting and packaging: Once proteins and lipids have been processed, they are sorted and packaged into vesicles at the trans face of the Golgi apparatus. These vesicles then transport their cargo to various destinations, such as lysosomes, plasma membrane, or extracellular space.
4. Intracellular transport: The Golgi apparatus serves as a central hub for intracellular trafficking, coordinating the movement of vesicles and other transport carriers between different organelles and cellular compartments.
5. Cell-cell communication: Some proteins that are processed and packaged in the Golgi apparatus are destined for secretion, playing crucial roles in cell-cell communication and maintaining tissue homeostasis.

In summary, the Golgi apparatus is a vital organelle involved in various cellular processes, including post-translational modification, sorting, packaging, and intracellular transport of proteins and lipids. Its proper functioning is essential for maintaining cellular homeostasis and overall organismal health.

Cell cycle proteins are a group of regulatory proteins that control the progression of the cell cycle, which is the series of events that take place in a eukaryotic cell leading to its division and duplication. These proteins can be classified into several categories based on their functions during different stages of the cell cycle.

The major groups of cell cycle proteins include:

1. Cyclin-dependent kinases (CDKs): CDKs are serine/threonine protein kinases that regulate key transitions in the cell cycle. They require binding to a regulatory subunit called cyclin to become active. Different CDK-cyclin complexes are activated at different stages of the cell cycle.
2. Cyclins: Cyclins are a family of regulatory proteins that bind and activate CDKs. Their levels fluctuate throughout the cell cycle, with specific cyclins expressed during particular phases. For example, cyclin D is important for the G1 to S phase transition, while cyclin B is required for the G2 to M phase transition.
3. CDK inhibitors (CKIs): CKIs are regulatory proteins that bind to and inhibit CDKs, thereby preventing their activation. CKIs can be divided into two main families: the INK4 family and the Cip/Kip family. INK4 family members specifically inhibit CDK4 and CDK6, while Cip/Kip family members inhibit a broader range of CDKs.
4. Anaphase-promoting complex/cyclosome (APC/C): APC/C is an E3 ubiquitin ligase that targets specific proteins for degradation by the 26S proteasome. During the cell cycle, APC/C regulates the metaphase to anaphase transition and the exit from mitosis by targeting securin and cyclin B for degradation.
5. Other regulatory proteins: Several other proteins play crucial roles in regulating the cell cycle, such as p53, a transcription factor that responds to DNA damage and arrests the cell cycle, and the polo-like kinases (PLKs), which are involved in various aspects of mitosis.

Overall, cell cycle proteins work together to ensure the proper progression of the cell cycle, maintain genomic stability, and prevent uncontrolled cell growth, which can lead to cancer.

The Fluorescent Antibody Technique (FAT) is a type of immunofluorescence assay used in laboratory medicine and pathology for the detection and localization of specific antigens or antibodies in tissues, cells, or microorganisms. In this technique, a fluorescein-labeled antibody is used to selectively bind to the target antigen or antibody, forming an immune complex. When excited by light of a specific wavelength, the fluorescein label emits light at a longer wavelength, typically visualized as green fluorescence under a fluorescence microscope.

The FAT is widely used in diagnostic microbiology for the identification and characterization of various bacteria, viruses, fungi, and parasites. It has also been applied in the diagnosis of autoimmune diseases and certain cancers by detecting specific antibodies or antigens in patient samples. The main advantage of FAT is its high sensitivity and specificity, allowing for accurate detection and differentiation of various pathogens and disease markers. However, it requires specialized equipment and trained personnel to perform and interpret the results.

HeLa cells are a type of immortalized cell line used in scientific research. They are derived from a cancer that developed in the cervical tissue of Henrietta Lacks, an African-American woman, in 1951. After her death, cells taken from her tumor were found to be capable of continuous division and growth in a laboratory setting, making them an invaluable resource for medical research.

HeLa cells have been used in a wide range of scientific studies, including research on cancer, viruses, genetics, and drug development. They were the first human cell line to be successfully cloned and are able to grow rapidly in culture, doubling their population every 20-24 hours. This has made them an essential tool for many areas of biomedical research.

It is important to note that while HeLa cells have been instrumental in numerous scientific breakthroughs, the story of their origin raises ethical questions about informed consent and the use of human tissue in research.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Anaphase is a stage in the cell division process called mitosis, where sister chromatids (the two copies of each chromosome formed during DNA replication) separate at the centromeres and move toward opposite poles of the cell. This separation is facilitated by the attachment of microtubules from the spindle apparatus to the kinetochores, protein structures located on the centromeres of each sister chromatid. Anaphase is followed by telophase, during which the nuclear membrane reforms around each set of separated chromosomes, and cytokinesis, the division of the cytoplasm to form two separate daughter cells.

Kinetochores are specialized protein structures that form on the centromere region of a chromosome. They play a crucial role in the process of cell division, specifically during mitosis and meiosis. The primary function of kinetochores is to connect the chromosomes to the microtubules of the spindle apparatus, which is responsible for separating the sister chromatids during cell division. Through this connection, kinetochores facilitate the movement of chromosomes towards opposite poles of the cell during anaphase, ensuring equal distribution of genetic material to each resulting daughter cell.

Metaphase is a phase in the cell division process (mitosis or meiosis) where the chromosomes align in the middle of the cell, also known as the metaphase plate or equatorial plane. During this stage, each chromosome consists of two sister chromatids attached to each other by a protein complex called the centromere. The spindle fibers from opposite poles of the cell attach to the centromeres of each chromosome, and through a process called congression, they align the chromosomes in the middle of the cell. This alignment allows for accurate segregation of genetic material during the subsequent anaphase stage.

Kinesin is not a medical term per se, but a term from the field of cellular biology. However, understanding how kinesins work is important in the context of medical and cellular research.

Kinesins are a family of motor proteins that play a crucial role in transporting various cargoes within cells, such as vesicles, organelles, and chromosomes. They move along microtubule filaments, using the energy derived from ATP hydrolysis to generate mechanical force and motion. This process is essential for several cellular functions, including intracellular transport, mitosis, and meiosis.

In a medical context, understanding kinesin function can provide insights into various diseases and conditions related to impaired intracellular transport, such as neurodegenerative disorders (e.g., Alzheimer's disease, Parkinson's disease, and Huntington's disease) and certain genetic disorders affecting motor neurons. Research on kinesins can potentially lead to the development of novel therapeutic strategies targeting these conditions.

Medical Definition:
Microtubule-associated proteins (MAPs) are a diverse group of proteins that bind to microtubules, which are key components of the cytoskeleton in eukaryotic cells. MAPs play crucial roles in regulating microtubule dynamics and stability, as well as in mediating interactions between microtubules and other cellular structures. They can be classified into several categories based on their functions, including:

1. Microtubule stabilizers: These MAPs promote the assembly of microtubules and protect them from disassembly by enhancing their stability. Examples include tau proteins and MAP2.
2. Microtubule dynamics regulators: These MAPs modulate the rate of microtubule polymerization and depolymerization, allowing for dynamic reorganization of the cytoskeleton during cell division and other processes. Examples include stathmin and XMAP215.
3. Microtubule motor proteins: These MAPs use energy from ATP hydrolysis to move along microtubules, transporting various cargoes within the cell. Examples include kinesin and dynein.
4. Adapter proteins: These MAPs facilitate interactions between microtubules and other cellular structures, such as membranes, organelles, or signaling molecules. Examples include MAP4 and CLASPs.

Dysregulation of MAPs has been implicated in several diseases, including neurodegenerative disorders like Alzheimer's disease (where tau proteins form abnormal aggregates called neurofibrillary tangles) and cancer (where altered microtubule dynamics can contribute to uncontrolled cell division).

Nocodazole is not a medical condition or disease, but rather a pharmacological agent used in medical research and clinical settings. It's a synthetic chemical compound that belongs to the class of drugs known as microtubule inhibitors. Nocodazole works by binding to and disrupting the dynamic assembly and disassembly of microtubules, which are important components of the cell's cytoskeleton and play a critical role in cell division.

Nocodazole is primarily used in research settings as a tool for studying cell biology and mitosis, the process by which cells divide. It can be used to synchronize cells in the cell cycle or to induce mitotic arrest, making it useful for investigating various aspects of cell division and chromosome behavior.

In clinical settings, nocodazole has been used off-label as a component of some cancer treatment regimens, particularly in combination with other chemotherapeutic agents. Its ability to disrupt microtubules can interfere with the proliferation of cancer cells and enhance the effectiveness of certain anti-cancer drugs. However, its use is not widespread due to potential side effects and the availability of alternative treatments.

The Mad2 (Mitotic Arrest Deficient 2) proteins are a part of the spindle assembly checkpoint (SAC), which is a crucial surveillance mechanism that ensures accurate chromosome segregation during cell division. The primary function of Mad2 proteins is to prevent the onset of anaphase until all chromosomes have achieved proper attachment and tension on the mitotic spindle.

Mad2 proteins exist in two major conformational states: open (O-Mad2) and closed (C-Mad2). The transition between these two forms plays a critical role in the regulation of the SAC. In response to unattached kinetochores, Mad2 proteins bind to and inhibit the anaphase-promoting complex/cyclosome (APC/C), thereby preventing premature chromosome separation.

There are two main isoforms of Mad2 in humans: Mad2L1 (Mad2A) and Mad2L2 (Mad2B). While both isoforms share similar functions, they exhibit distinct biochemical properties and interact with other SAC components differently. Dysregulation of the Mad2 proteins has been implicated in various diseases, including cancer and neurological disorders.

Aurora kinases are a family of serine/threonine protein kinases that play crucial roles in the regulation of cell division. There are three members of the Aurora kinase family, designated as Aurora A, Aurora B, and Aurora C. These kinases are involved in the proper separation of chromosomes during mitosis and meiosis, and their dysregulation has been implicated in various types of cancer.

Aurora A is primarily located at the centrosomes and spindle poles during cell division, where it regulates centrosome maturation, bipolar spindle formation, and chromosome segregation. Aurora B, on the other hand, is a component of the chromosomal passenger complex (CPC) that localizes to the centromeres during prophase and moves to the spindle midzone during anaphase. It plays essential roles in kinetochore-microtubule attachment, chromosome alignment, and cytokinesis. Aurora C is most similar to Aurora B and appears to have overlapping functions with it, although its specific roles are less well understood.

Dysregulation of Aurora kinases has been associated with various types of cancer, including breast, ovarian, colon, and lung cancers. Overexpression or amplification of Aurora A is observed in many cancers, leading to chromosomal instability and aneuploidy. Inhibition of Aurora kinases has emerged as a potential therapeutic strategy for cancer treatment, with several small molecule inhibitors currently under investigation in clinical trials.

Chromosomes are thread-like structures that exist in the nucleus of cells, carrying genetic information in the form of genes. They are composed of DNA and proteins, and are typically present in pairs in the nucleus, with one set inherited from each parent. In humans, there are 23 pairs of chromosomes for a total of 46 chromosomes. Chromosomes come in different shapes and forms, including sex chromosomes (X and Y) that determine the biological sex of an individual. Changes or abnormalities in the number or structure of chromosomes can lead to genetic disorders and diseases.

Dyneins are a type of motor protein that play an essential role in the movement of cellular components and structures within eukaryotic cells. They are responsible for generating force and motion along microtubules, which are critical components of the cell's cytoskeleton. Dyneins are involved in various cellular processes, including intracellular transport, organelle positioning, and cell division.

There are several types of dyneins, but the two main categories are cytoplasmic dyneins and axonemal dyneins. Cytoplasmic dyneins are responsible for moving various cargoes, such as vesicles, organelles, and mRNA complexes, toward the minus-end of microtubules, which is usually located near the cell center. Axonemal dyneins, on the other hand, are found in cilia and flagella and are responsible for their movement by sliding adjacent microtubules past each other.

Dyneins consist of multiple subunits, including heavy chains, intermediate chains, light-intermediate chains, and light chains. The heavy chains contain the motor domain that binds to microtubules and hydrolyzes ATP to generate force. Dysfunction in dynein proteins has been linked to various human diseases, such as neurodevelopmental disorders, ciliopathies, and cancer.

Telophase is a phase in the cell division process (mitosis or meiosis) where the chromosomes reach their most condensed form and move to the poles of the cell. The nuclear membrane begins to reform around each set of chromosomes, and the spindle fibers that were used to separate the chromosomes break down. This phase is followed by cytokinesis, where the cytoplasm of the cell divides, resulting in two separate daughter cells. In telophase I of meiosis, crossing over between homologous chromosomes has already occurred during prophase I and sister chromatids remain together until anaphase II.

M Phase cell cycle checkpoints are control mechanisms that ensure the proper completion of the M phase (mitosis or meiosis) of the cell cycle. These checkpoints verify that certain conditions are met before the cell proceeds to the next phase of the cell cycle, thus helping to maintain genomic stability and prevent errors such as chromosomal mutations or aneuploidy.

There are two main M Phase cell cycle checkpoints:

1. The G2/M Checkpoint: This checkpoint is activated at the end of the G2 phase and verifies that all DNA has been replicated accurately, and that there are no DNA damages or other issues that could interfere with mitosis. If any problems are detected, the cell cycle is halted until they can be resolved.
2. The Mitotic Spindle Checkpoint: This checkpoint ensures that all chromosomes have attached properly to the spindle apparatus and that they will be equally distributed to the two resulting daughter cells during mitosis. If any chromosomes are not properly attached or if there is an issue with the spindle apparatus, the cell cycle is paused until these problems are corrected.

These checkpoints play a crucial role in maintaining genomic stability and preventing the development of cancer and other diseases.

Cytokinesis is the part of the cell division process (mitosis or meiosis) in which the cytoplasm of a single eukaryotic cell divides into two daughter cells. It usually begins after telophase, and it involves the constriction of a contractile ring composed of actin filaments and myosin motor proteins that forms at the equatorial plane of the cell. This results in the formation of a cleavage furrow, which deepens and eventually leads to the physical separation of the two daughter cells. Cytokinesis is essential for cell reproduction and growth in multicellular organisms, and its failure can lead to various developmental abnormalities or diseases.

Fluorescence microscopy is a type of microscopy that uses fluorescent dyes or proteins to highlight and visualize specific components within a sample. In this technique, the sample is illuminated with high-energy light, typically ultraviolet (UV) or blue light, which excites the fluorescent molecules causing them to emit lower-energy, longer-wavelength light, usually visible light in the form of various colors. This emitted light is then collected by the microscope and detected to produce an image.

Fluorescence microscopy has several advantages over traditional brightfield microscopy, including the ability to visualize specific structures or molecules within a complex sample, increased sensitivity, and the potential for quantitative analysis. It is widely used in various fields of biology and medicine, such as cell biology, neuroscience, and pathology, to study the structure, function, and interactions of cells and proteins.

There are several types of fluorescence microscopy techniques, including widefield fluorescence microscopy, confocal microscopy, two-photon microscopy, and total internal reflection fluorescence (TIRF) microscopy, each with its own strengths and limitations. These techniques can provide valuable insights into the behavior of cells and proteins in health and disease.

An oocyte, also known as an egg cell or female gamete, is a large specialized cell found in the ovary of female organisms. It contains half the number of chromosomes as a normal diploid cell, as it is the product of meiotic division. Oocytes are surrounded by follicle cells and are responsible for the production of female offspring upon fertilization with sperm. The term "oocyte" specifically refers to the immature egg cell before it reaches full maturity and is ready for fertilization, at which point it is referred to as an ovum or egg.

Protein-Serine-Threonine Kinases (PSTKs) are a type of protein kinase that catalyzes the transfer of a phosphate group from ATP to the hydroxyl side chains of serine or threonine residues on target proteins. This phosphorylation process plays a crucial role in various cellular signaling pathways, including regulation of metabolism, gene expression, cell cycle progression, and apoptosis. PSTKs are involved in many physiological and pathological processes, and their dysregulation has been implicated in several diseases, such as cancer, diabetes, and neurodegenerative disorders.

A Microtubule-Organizing Center (MTOC) is a cellular structure that organizes and nucleates microtubules, which are important components of the cytoskeleton. MTOCs are involved in various cellular processes such as cell division, intracellular transport, and maintenance of cell shape. The largest and most well-known MTOC is the centrosome, which is typically located near the nucleus of animal cells. However, there are other types of MTOCs, including the basal bodies of cilia and flagella, and the microtubule-organizing centers found in plant cells called plastids. Overall, MTOCs play a crucial role in maintaining the structural integrity and organization of the cell.

Saccharomyces cerevisiae proteins are the proteins that are produced by the budding yeast, Saccharomyces cerevisiae. This organism is a single-celled eukaryote that has been widely used as a model organism in scientific research for many years due to its relatively simple genetic makeup and its similarity to higher eukaryotic cells.

The genome of Saccharomyces cerevisiae has been fully sequenced, and it is estimated to contain approximately 6,000 genes that encode proteins. These proteins play a wide variety of roles in the cell, including catalyzing metabolic reactions, regulating gene expression, maintaining the structure of the cell, and responding to environmental stimuli.

Many Saccharomyces cerevisiae proteins have human homologs and are involved in similar biological processes, making this organism a valuable tool for studying human disease. For example, many of the proteins involved in DNA replication, repair, and recombination in yeast have human counterparts that are associated with cancer and other diseases. By studying these proteins in yeast, researchers can gain insights into their function and regulation in humans, which may lead to new treatments for disease.

Microtubule proteins are a class of structural proteins that make up the microtubules, which are key components of the cytoskeleton in eukaryotic cells. The main microtubule protein is tubulin, which exists in two forms: alpha-tubulin and beta-tubulin. These tubulins polymerize to form heterodimers, which then assemble into protofilaments, which in turn aggregate to form hollow microtubules. Microtubules are dynamic structures that undergo continuous assembly and disassembly, and they play crucial roles in various cellular processes, including intracellular transport, cell division, and maintenance of cell shape. Other microtubule-associated proteins (MAPs) also bind to microtubules and regulate their stability, dynamics, and interactions with other cellular structures.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Electron microscopy (EM) is a type of microscopy that uses a beam of electrons to create an image of the sample being examined, resulting in much higher magnification and resolution than light microscopy. There are several types of electron microscopy, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and reflection electron microscopy (REM).

In TEM, a beam of electrons is transmitted through a thin slice of the sample, and the electrons that pass through the sample are focused to form an image. This technique can provide detailed information about the internal structure of cells, viruses, and other biological specimens, as well as the composition and structure of materials at the atomic level.

In SEM, a beam of electrons is scanned across the surface of the sample, and the electrons that are scattered back from the surface are detected to create an image. This technique can provide information about the topography and composition of surfaces, as well as the structure of materials at the microscopic level.

REM is a variation of SEM in which the beam of electrons is reflected off the surface of the sample, rather than scattered back from it. This technique can provide information about the surface chemistry and composition of materials.

Electron microscopy has a wide range of applications in biology, medicine, and materials science, including the study of cellular structure and function, disease diagnosis, and the development of new materials and technologies.

Nuclear proteins are a category of proteins that are primarily found in the nucleus of a eukaryotic cell. They play crucial roles in various nuclear functions, such as DNA replication, transcription, repair, and RNA processing. This group includes structural proteins like lamins, which form the nuclear lamina, and regulatory proteins, such as histones and transcription factors, that are involved in gene expression. Nuclear localization signals (NLS) often help target these proteins to the nucleus by interacting with importin proteins during active transport across the nuclear membrane.

Gamma motor neurons are a type of motor neuron found in the spinal cord and brainstem. They innervate the intrafusal fibers of muscle spindles, which are specialized sensory receptors that detect changes in muscle length and stretch. Gamma motor neurons help regulate the sensitivity of muscle spindles by adjusting the tension in the intrafusal fibers. This is important for maintaining muscle tone, coordinating movements, and providing feedback to the brain about the position and movement of body parts.

Gamma motor neurons are activated by various signals from the brain, including descending pathways that carry information about planned movements and sensory inputs from other parts of the nervous system. They are also influenced by reflex circuits that help regulate muscle tone and posture. Dysfunction in gamma motor neurons has been implicated in several neurological conditions, including spasticity, dystonia, and some forms of muscle weakness.

Centrioles are small, cylindrical structures found in the centrosome of animal cells. They play a crucial role in organizing the microtubules that make up the cell's cytoskeleton and are also involved in the formation of the spindle apparatus during cell division. A typical centriole is made up of nine sets of triplet microtubules arranged in a ring-like fashion around a central hub or core.

Centrioles have two main functions:

1. Microtubule Organization: Centrioles serve as the primary site for microtubule nucleation and organization within the cell. They help to form the mitotic spindle during cell division, which is responsible for separating replicated chromosomes into two identical sets that are distributed equally between the two daughter cells.

2. Formation of Cilia and Flagella: In specialized cells, centrioles can also function as basal bodies for the formation of cilia and flagella. These hair-like structures protrude from the cell surface and play a role in cell movement and the movement of extracellular fluids over the cell surface.

It is important to note that plants and fungi do not have centrioles, and their cells use alternative mechanisms for microtubule organization and cell division.

The cell cycle is a series of events that take place in a cell leading to its division and duplication. It consists of four main phases: G1 phase, S phase, G2 phase, and M phase.

During the G1 phase, the cell grows in size and synthesizes mRNA and proteins in preparation for DNA replication. In the S phase, the cell's DNA is copied, resulting in two complete sets of chromosomes. During the G2 phase, the cell continues to grow and produces more proteins and organelles necessary for cell division.

The M phase is the final stage of the cell cycle and consists of mitosis (nuclear division) and cytokinesis (cytoplasmic division). Mitosis results in two genetically identical daughter nuclei, while cytokinesis divides the cytoplasm and creates two separate daughter cells.

The cell cycle is regulated by various checkpoints that ensure the proper completion of each phase before progressing to the next. These checkpoints help prevent errors in DNA replication and division, which can lead to mutations and cancer.

Prophase is the first phase of mitosis, the process by which eukaryotic cells divide and reproduce. During prophase, the chromosomes condense and become visible. The nuclear envelope breaks down, allowing the spindle fibers to attach to the centromeres of each chromatid in the chromosome. This is a critical step in preparing for the separation of genetic material during cell division. Prophase is also marked by the movement of the centrosomes to opposite poles of the cell, forming the mitotic spindle.

"Saccharomyces cerevisiae" is not typically considered a medical term, but it is a scientific name used in the field of microbiology. It refers to a species of yeast that is commonly used in various industrial processes, such as baking and brewing. It's also widely used in scientific research due to its genetic tractability and eukaryotic cellular organization.

However, it does have some relevance to medical fields like medicine and nutrition. For example, certain strains of S. cerevisiae are used as probiotics, which can provide health benefits when consumed. They may help support gut health, enhance the immune system, and even assist in the digestion of certain nutrients.

In summary, "Saccharomyces cerevisiae" is a species of yeast with various industrial and potential medical applications.

Prometaphase is a stage in the cell division process called mitosis, where the nuclear membrane has broken down and the chromosomes are now moved into the center of the cell, also known as the metaphase plate. This movement is facilitated by the mitotic spindle, which attaches to specialized structures on the chromosomes called kinetochores. The prometaphase stage follows prophase and precedes metaphase in the mitosis process. It's characterized by the beginning of chromosome separation and the reorganization of the cell for the upcoming division into two daughter cells.

Organoids are 3D tissue cultures grown from stem cells that mimic the structure and function of specific organs. They are used in research to study development, disease, and potential treatments. The term "organoid" refers to the fact that these cultures can organize themselves into structures that resemble rudimentary organs, with differentiated cell types arranged in a pattern similar to their counterparts in the body. Organoids can be derived from various sources, including embryonic stem cells, induced pluripotent stem cells (iPSCs), or adult stem cells, and they provide a valuable tool for studying complex biological processes in a controlled laboratory setting.

A centromere is a specialized region found on chromosomes that plays a crucial role in the separation of replicated chromosomes during cell division. It is the point where the sister chromatids (the two copies of a chromosome formed during DNA replication) are joined together. The centromere contains highly repeated DNA sequences and proteins that form a complex structure known as the kinetochore, which serves as an attachment site for microtubules of the mitotic spindle during cell division.

During mitosis or meiosis, the kinetochore facilitates the movement of chromosomes by interacting with the microtubules, allowing for the accurate distribution of genetic material to the daughter cells. Centromeres can vary in their position and structure among different species, ranging from being located near the middle of the chromosome (metacentric) to being positioned closer to one end (acrocentric). The precise location and characteristics of centromeres are essential for proper chromosome segregation and maintenance of genomic stability.

Cell polarity refers to the asymmetric distribution of membrane components, cytoskeleton, and organelles in a cell. This asymmetry is crucial for various cellular functions such as directed transport, cell division, and signal transduction. The plasma membrane of polarized cells exhibits distinct domains with unique protein and lipid compositions that define apical, basal, and lateral surfaces of the cell.

In epithelial cells, for example, the apical surface faces the lumen or external environment, while the basolateral surface interacts with other cells or the extracellular matrix. The establishment and maintenance of cell polarity are regulated by various factors including protein complexes, lipids, and small GTPases. Loss of cell polarity has been implicated in several diseases, including cancer and neurological disorders.

Birefringence is a property of certain materials, such as crystals and some plastics, to split a beam of light into two separate beams with different polarization states and refractive indices when the light passes through the material. This phenomenon arises due to the anisotropic structure of these materials, where their physical properties vary depending on the direction of measurement.

When a unpolarized or partially polarized light beam enters a birefringent material, it gets separated into two orthogonally polarized beams called the ordinary and extraordinary rays. These rays propagate through the material at different speeds due to their distinct refractive indices, resulting in a phase delay between them. Upon exiting the material, the recombination of these two beams can produce various optical effects, such as double refraction or interference patterns, depending on the thickness and orientation of the birefringent material and the polarization state of the incident light.

Birefringence has numerous applications in optics, including waveplates, polarizing filters, stress analysis, and microscopy techniques like phase contrast and differential interference contrast imaging.

Protein transport, in the context of cellular biology, refers to the process by which proteins are actively moved from one location to another within or between cells. This is a crucial mechanism for maintaining proper cell function and regulation.

Intracellular protein transport involves the movement of proteins within a single cell. Proteins can be transported across membranes (such as the nuclear envelope, endoplasmic reticulum, Golgi apparatus, or plasma membrane) via specialized transport systems like vesicles and transport channels.

Intercellular protein transport refers to the movement of proteins from one cell to another, often facilitated by exocytosis (release of proteins in vesicles) and endocytosis (uptake of extracellular substances via membrane-bound vesicles). This is essential for communication between cells, immune response, and other physiological processes.

It's important to note that any disruption in protein transport can lead to various diseases, including neurological disorders, cancer, and metabolic conditions.

CDC20 proteins are a type of regulatory protein that play a crucial role in the cell cycle, which is the process by which cells grow and divide. Specifically, CDC20 proteins are involved in the transition from metaphase to anaphase during mitosis, the phase of the cell cycle where chromosomes are separated and distributed to two daughter cells.

CDC20 proteins function as part of a larger complex called the anaphase-promoting complex/cyclosome (APC/C), which targets specific proteins for degradation by the proteasome. During metaphase, CDC20 binds to the APC/C and helps to activate it, leading to the degradation of securin and cyclin B, two proteins that are essential for maintaining the proper attachment of chromosomes to the spindle apparatus.

Once these proteins are degraded, the sister chromatids can be separated and moved to opposite poles of the cell, allowing for the completion of mitosis and the formation of two genetically identical daughter cells. In addition to their role in mitosis, CDC20 proteins have also been implicated in other cellular processes, including meiosis, DNA damage repair, and apoptosis.

Ran GTP-binding protein, also known as Ran or Ras-related nuclear protein, is a small GTPase that plays a crucial role in the regulation of nucleocytoplasmic transport in eukaryotic cells. It binds to and hydrolyzes guanosine triphosphate (GTP) and acts as a molecular switch that controls various cellular processes, including nuclear import and export, mitotic spindle assembly, and nuclear envelope formation during cell division.

Ran exists in two interconvertible forms: the GTP-bound form, which is active and can bind to importin-β and other transport factors, and the GDP-bound form, which is inactive and localized mainly in the cytoplasm. The RanGAP protein (Ran GTPase-activating protein) catalyzes the hydrolysis of GTP to GDP, while the RanGEF protein (Ran guanine nucleotide exchange factor) facilitates the exchange of GDP for GTP.

The regulation of Ran GTPase activity is critical for maintaining the proper functioning of the nuclear transport machinery and ensuring the integrity of the genome. Dysregulation of Ran GTPase has been implicated in various human diseases, including cancer, neurodegenerative disorders, and viral infections.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Interphase is a phase in the cell cycle during which the cell primarily performs its functions of growth and DNA replication. It is the longest phase of the cell cycle, consisting of G1 phase (during which the cell grows and prepares for DNA replication), S phase (during which DNA replication occurs), and G2 phase (during which the cell grows further and prepares for mitosis). During interphase, the chromosomes are in their relaxed, extended form and are not visible under the microscope. Interphase is followed by mitosis, during which the chromosomes condense and separate to form two genetically identical daughter cells.

"Xenopus proteins" refer to the proteins that are expressed or isolated from the Xenopus species, which are primarily used as model organisms in biological and biomedical research. The most commonly used Xenopus species for research are the African clawed frogs, Xenopus laevis and Xenopus tropicalis. These proteins play crucial roles in various cellular processes and functions, and they serve as valuable tools to study different aspects of molecular biology, developmental biology, genetics, and biochemistry.

Some examples of Xenopus proteins that are widely studied include:

1. Xenopus Histones: These are the proteins that package DNA into nucleosomes, which are the fundamental units of chromatin in eukaryotic cells. They play a significant role in gene regulation and epigenetic modifications.
2. Xenopus Cyclins and Cyclin-dependent kinases (CDKs): These proteins regulate the cell cycle and control cell division, differentiation, and apoptosis.
3. Xenopus Transcription factors: These proteins bind to specific DNA sequences and regulate gene expression during development and in response to various stimuli.
4. Xenopus Signaling molecules: These proteins are involved in intracellular signaling pathways that control various cellular processes, such as cell growth, differentiation, migration, and survival.
5. Xenopus Cytoskeletal proteins: These proteins provide structural support to the cells and regulate their shape, motility, and organization.
6. Xenopus Enzymes: These proteins catalyze various biochemical reactions in the cell, such as metabolic pathways, DNA replication, transcription, and translation.

Overall, Xenopus proteins are essential tools for understanding fundamental biological processes and have contributed significantly to our current knowledge of molecular biology, genetics, and developmental biology.

Cells divide along the line connecting two centrosomes of the spindle apparatus. After formation, the spindle apparatus ... The cellular spindle apparatus includes the spindle microtubules, associated proteins, which include kinesin and dynein ... The spindle apparatus is vaguely ellipsoid in cross section and tapers at the ends. In the wide middle portion, known as the ... Media related to Spindle apparatus at Wikimedia Commons (CS1 maint: multiple names: authors list, Articles with short ...
meiotic spindle See spindle apparatus. melting The denaturation of a double-stranded nucleic acid into two single strands, ... mitotic recombination mitotic segregation mitotic spindle See spindle apparatus. mixoploidy The presence of more than one ... spectral karyotype (SKY) spindle apparatus spliceosome splicing See genetic engineering. split-gene ssDNA See single-stranded ... and the mitotic spindle forms. protein A polymeric macromolecule composed of one or more long chains of amino acids linked by ...
Ptacin, JL; Lee, SF; Garner, EC; Toro, E; Eckart, M; Comolli, LR; Moerner, WE; Shapiro, L (Aug 2010). "A spindle-like apparatus ... "Stochastic Self-Assembly of ParB Proteins Builds the Bacterial DNA Segregation Apparatus". Cell Systems. 1 (2): 163-73. doi: ...
During mitosis Par14 associates to the spindle apparatus. In vitro experiments demonstrated that Par14 may be involved in ...
The spindle apparatus rotates in the round cell and after several minutes the spindle position is stabilised preferentially ... It is at this rounding stage that the decision on the orientation of the cell division is made by the spindle apparatus. ... The cell then divides along the spindle apparatus orientation. The first insights into how cells could remember their long axis ... the rule emphasizes the cell shape as a default mechanism of spindle apparatus orientation. Hertwig's rule predicts cell ...
The funnel locking-apparatus are small and oval to spindle-shaped. A single cartilaginous tubercle is present at the mantle ... In this posture, they rotate around their spindle-shaped digestive glands, the only internal organs of the squid clearly ...
This gene encodes a protein associated with the mitotic spindle apparatus. The encoded protein may be involved in the ... 2003). "The mitotic-spindle-associated protein astrin is essential for progression through mitosis". J. Cell Sci. 115 (Pt 21): ... Shao X, Xue J, van der Hoorn FA (2001). "Testicular protein Spag5 has similarity to mitotic spindle protein Deepest and binds ... 2007). "hNinein is required for targeting spindle-associated protein Astrin to the centrosome during the S and G2 phases" (PDF ...
The two centrosomes polymerize tubulin to help form a microtubule spindle apparatus. Motor proteins then push the centrosomes ... With respect to the symmetry of the spindle apparatus during metaphase, an approximately axially symmetric (centered) shape is ... Although centrosomes help organize microtubule assembly, they are not essential for the formation of the spindle apparatus, ... Finally, a third criterion is the location of the central spindle in case of closed pleuromitosis: "extranuclear" (spindle ...
This requires the spindle apparatus in these cells to be positioned asymmetrically. She discovered a role for proteins that ... "A liquid-like spindle domain promotes acentrosomal spindle assembly in mammalian oocytes". Science. 364 (6447). Bibcode:2019Sci ... and established essential functions for actin and a liquid-like spindle domain in acentrosomal spindle assembly. Recent work ... She used these methods to study the organization and positioning of the spindle in mouse oocytes. In 2009, Schuh became a Group ...
This spindle apparatus consists of microtubules, microfilaments and a complex network of various proteins. During metaphase, ... the chromosomes line up using the spindle apparatus in the middle of the cell along the equatorial plate. The chromosomes move ... Prophase is the initial phase when spindle fibers appear that function to move the chromosomes toward opposite poles. ... Both require vesicular secretions by the Golgi apparatus for resealing and formation of the cytoskeletal network, in addition ...
2013 find the parasite to place itself close to the spindle apparatus during mitosis. This position allows it to follow the ... spindle through into the next generation of cells. The genome was sequenced by Gardner et al. 2005, finding just over 4,000 ...
The spindle apparatus of the second meiotic division appears at the time of ovulation. If no fertilization occurs, the oocyte ...
During the first division, chromosomes may lag behind and become lost from the spindle apparatus. Extra nuclei are occasionally ... During the second division the extra chromosomes tend to form their own spindle apparatus and divide. Megasporogenesis is ...
... maintains bipolar microtubule spindle apparatus in dividing cells and shares redundant functions with KIF11. KIF15 is ... KIF15 maintains half spindle separation by opposing forces generated by other motor proteins. KIF15 co-localizes with ... Vanneste D, Takagi M, Imamoto N, Vernos I (November 2009). "The role of Hklp2 in the stabilization and maintenance of spindle ... Courtois A, Schuh M, Ellenberg J, Hiiragi T (August 2012). "The transition from meiotic to mitotic spindle assembly is gradual ...
... microtubules and the spindle apparatus". European Journal of Cell Biology. 79 (4): 240-51. doi:10.1078/S0171-9335(04)70027-8. ... During interphase, CKIδ associates with the Golgi Apparatus and appears to regulate the budding of clathrin coated vesicles ... Bingham EW, Farrel HM (June 1974). "Casein kinase from the Golgi apparatus of lactating mammary gland". The Journal of ... and cytoplasm of eukaryotes and additionally in the mitotic spindle in mammalian cells. The family members have the highest ...
"Transforming acidic coiled-coil-containing protein 4 interacts with centrosomal AKAP350 and the mitotic spindle apparatus". J. ... Alternate splicing of this gene results in many isoforms that localize to the centrosome and the Golgi apparatus, and interact ... Shanks RA, Larocca MC, Berryman M, Edwards JC, Urushidani T, Navarre J, Goldenring JR (2002). "AKAP350 at the Golgi apparatus. ... "AKAP350 interaction with cdc42 interacting protein 4 at the Golgi apparatus". Mol. Biol. Cell. 15 (6): 2771-81. doi:10.1091/mbc ...
"Transforming acidic coiled-coil-containing protein 4 interacts with centrosomal AKAP350 and the mitotic spindle apparatus". J. ... "The transforming acidic coiled coil 3 protein is essential for spindle-dependent chromosome alignment and mitotic survival". J ...
... sister chromatid adhesion and rearrange the spindle apparatus. During meiosis, there are 2 sets of cell divisions, the second ... and mitotic/meiotic spindle defects that could result in insertions, deletions, abnormal segregation, DNA bridging, and ...
In the first meiotic division, the homologs are segregated to separate daughter cells by the spindle apparatus. The cells then ... Over time the MTOCs merge until two poles have formed, generating a barrel shaped spindle. In human oocytes spindle microtubule ... Unlike mitotic cells, human and mouse oocytes do not have centrosomes to produce the meiotic spindle. In mice, approximately 80 ... The microtubules that make up the spindle network disappear, and a new nuclear membrane surrounds each haploid set. The ...
CK1δ is involved in the regulation of microtubule polymerization and stability of the spindle apparatus and centrosomes during ... microtubules and the spindle apparatus". European Journal of Cell Biology. 79 (4): 240-51. doi:10.1078/S0171-9335(04)70027-8. ... Roof DM, Meluh PB, Rose MD (July 1992). "Kinesin-related proteins required for assembly of the mitotic spindle". The Journal of ... centrosomes or spindle poles. While the present NLS is not sufficient for nuclear localization of CK1δ, the presence of the ...
During anaphase, daughter chromosomes join at the poles of the spindle apparatus, and then move farther apart. During telophase ...
Spindle checkpoint Kinetochore Spindle apparatus "Examining chromosome-microtubule attachment". Archived from the original on 3 ... Instead, the spindle must actively exert forces on one of the two kinetochores to relocate it to the proper, outer edge of the ... Such attachment errors are common during the early stages of spindle formation, but they are mostly corrected before the start ... During the division process, errors commonly occur in attaching the chromosomes to the spindle, estimated to affect 86 to 90 ...
During cytokinesis the spindle apparatus partitions and transports duplicated chromatids into the cytoplasm of the separating ... The central spindle (or spindle midzone) forms when non-kinetochore microtubule fibers are bundled between the spindle poles. A ... In short, the self-assembly of central spindle is initiated through the phosphoregulation of multiple central spindle ... where signals from two poles are somehow focused into a ring at the spindle. A second possibility, called the central spindle ...
... was recognized particularly for contributing to discovery of the attachment of chromosomes to the mitotic spindle apparatus. ... Brinkley is attempting to uncover the molecular basis of errors and defects in the nucleus and mitotic apparatus that cause ...
Tricellular junctions exert a pulling force on the spindle apparatus and serve as a geometrical clues to determine orientation ... In some Drosophila epithelia, during cell divisions tricellular junctions establish physical contact with spindle apparatus ...
During mitosis, clathrin binds to the spindle apparatus, in complex with two other proteins: TACC3 and ch-TOG/CKAP5. Clathrin ... Royle SJ, Bright NA, Lagnado L (April 2005). "Clathrin is required for the function of the mitotic spindle". Nature. 434 (7037 ... August 2013). "Coordination of adjacent domains mediates TACC3-ch-TOG-clathrin assembly and mitotic spindle binding". The ... August 2013). "Coordination of adjacent domains mediates TACC3-ch-TOG-clathrin assembly and mitotic spindle binding". The ...
... are properly aligned to the spindle apparatus. Only then, SAC releases its inhibition of the anaphase promoting complex (APC), ... The spindle assembly checkpoint (SAC) is a molecular safe-guarding mechanism that governs proper chromosome segregation in ... Sun, S.-C.; Kim, N.-H. (14 November 2011). "Spindle assembly checkpoint and its regulators in meiosis". Human Reproduction ... The cohesin complex is responsible for keeping together sister chromatids and provides binding sites for spindle attachment. ...
... microtubules gather at opposite poles and begin to form the spindle apparatus at locations called foci. The mitotic spindle is ... The organization of the spindle apparatus is associated instead with foci at opposite poles of the cell or is mediated by ... as the meiotic prophase ends with the spindle apparatus beginning to form, and the nuclear membrane beginning to break down.: ... Plant cells do not have centrosomes and the chromosomes can nucleate microtubule assembly into the mitotic apparatus. In plant ...
Yoshio Masui cell cycle Cdk1 cyclin DNA replication nuclear transport spindle apparatus condensin cohesin Lohka MJ, Masui Y ( ... 1985). "Induction of nuclear envelope breakdown, chromosome condensation, and spindle formation in cell-free extracts". J. Cell ... it undergoes a series of structural changes and is eventually converted into a set of M phase chromosomes with bipolar spindles ... other than cyclin B is necessary for initiating chromosome segregation Discovery of a mechanism of spindle assembly that ...
In several site excavations ancient instruments were found, mainly spindle whorls apparatus (malacates), in the remains of some ... On the one hand, they have often been associated with spindle whorls, although there is little ethnographic documentation to ... Its most definite function, more than any of the remaining ceramic artifacts, always considered as spindle whorls. However, as ...
Cells divide along the line connecting two centrosomes of the spindle apparatus. After formation, the spindle apparatus ... The cellular spindle apparatus includes the spindle microtubules, associated proteins, which include kinesin and dynein ... The spindle apparatus is vaguely ellipsoid in cross section and tapers at the ends. In the wide middle portion, known as the ... Media related to Spindle apparatus at Wikimedia Commons (CS1 maint: multiple names: authors list, Articles with short ...
Home / Products tagged "Spindle apparatus.". Spindle apparatus.. Showing the single result. Default sorting. Sort by popularity ...
"Mitotic Spindle Apparatus" by people in this website by year, and whether "Mitotic Spindle Apparatus" was a major or minor ... "Mitotic Spindle Apparatus" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH (Medical ... Below are the most recent publications written about "Mitotic Spindle Apparatus" by people in Profiles. ... Below are MeSH descriptors whose meaning is more general than "Mitotic Spindle Apparatus". ...
Here, we report that PSMA is localized to a membrane compartment in the vicinity of mitotic spindle … ... Spindle Apparatus / metabolism * Ubiquitin-Protein Ligase Complexes / metabolism* Substances * CCNB1 protein, human ... Here, we report that PSMA is localized to a membrane compartment in the vicinity of mitotic spindle poles and associates with ... prematurely degrade cyclin B and exit mitosis due to increased APC activity and incomplete inactivation of APC by the spindle ...
Spindle Apparatus / ultrastructure * Tumor Suppressor Protein p53 / physiology Substances * TP53 protein, human ... A double reporter-in which the mitotic spindle was labelled by endogenously tagged tubulin and the cell membrane by ... tubulin tagging with TP53 knock-out revealed that TP53 is involved in controlling hepatocyte ploidy and mitotic spindle ...
1) centrosome (AC-24); 2) spindle apparatus (AC-25); 3) NuMA-like (AC-26); 4) mid-body (AC-27); 5) mitotic chromosomal (AC-28) ... SSMISFPS - mitotic spindle fibers positive. Variable Name: SSMISFPS. SAS Label: mitotic spindle fibers positive. English Text: ... SSMISFSG - mitotic spindle fibers signal. Variable Name: SSMISFSG. SAS Label: mitotic spindle fibers signal. English Text: ... mitotic spindle fibers positive. Target: Both males and females 12 YEARS - 150 YEARS. Code or Value. Value Description. Count. ...
Molecular organization of the zygotic spindle apparatus in non-rodent embryos. Project Identification MUNI/IGA/1127/2021 ...
Here we combine the first large-scale serial electron tomography of whole mitotic spindles in early C. elegans embryos with ... A connection between centrosomes and chromosomes is a key feature of mitotic spindles. Here the authors generate 3D ... We classify them as kinetochore (KMTs), spindle (SMTs) or astral microtubules (AMTs) according to their positions, and quantify ... elegansembryos and show that chromosomes are anchored by the entire spindle network and that connections through kinetochore ...
Armature spindle upper pressure axial bearing apparatus CN110539158A (en) * 2019-08-22. 2019-12-06. 深圳市阿尓法智慧科技有限公司. rotor ... Armature spindle upper pressure axial bearing apparatus CN110539158A (en) * 2019-08-22. 2019-12-06. 深圳市阿尓法智慧科技有限公司. rotor ... The apparatus for assembling of rotor bearing Cited By (12). * Cited by examiner, † Cited by third party. Publication number. ... 3. the apparatus for assembling of rotor bearing according to claim 2, is characterized in that: the
Investigations into the assembly of mitotic and meiotic spindle apparatus components. Areas of interest include kinetochore ... functions, spindle assembly checkpoints, centrosomes, and chromosome attachment and movement. Rita Miller, Ph.D.. Email: rita. ...
Two major autoantigen-antibody systems of the mitotic spindle apparatus. Arthritis Rheum 1996;39:1643-53. ... mitotic spindle apparatus, cytosol, cytoplasmic organelles and cell membranes. Detection of anti-cellular antibodies of the ANA ...
... kinesin-like spindle protein HKSP, and thyroid receptor interacting protein 5 (TRIP5)) is a 119 kD kinesin-like protein family ... Phosphorylation on Thr927 by Cdc2 allows association with spindle apparatus Gene ID 3832 View all products for this Gene ID ... hEg5 is modified by phosphorylation on Thr927 by Cdc2 to allow association with the spindle apparatus. Eg5 has been shown to ... Centrosomes, spindle microtubules, intracellular bridge. Function Motor protein required for establishing bipolar spindle ...
... high speed micro-spindle , Author: Jong-Kweon Park, Seung-Kook Ro, Byung-Sub Kim, Woo-Cheol Shin, and Hyeon-Hwa Lee ... 22] "Apparatus of the Micro Spindle," Korean Patent 0836228, 2008.. *[23] "The Compacted Air Spindle Apparatus," Korean Patent ... 21] W.-C. Shin, S.-K. Ro, H.-W. Park, and J.-K. Park, "Development of Micro-spindle System with the Tool Clamping Device Using ... 24] J.-H. Kyung, J.-S. Choi, W.-C. Shin, S.-K. Ro, and J.-K. Park, "Study on Magnetically Suspended Micro High-Speed Spindle ...
A microtubule is a cellular structure, part of what is called the mitotic spindle apparatus, which normally determines cleavage ...
... to the genetic material or kinetochores and spindle apparatus. ... of long fibers with mitotic spindle and chromosome migration. ... That is, fibers may directly or indirectly interact with the spindle mechanism involved in chromosomal separation during cell ...
This gene encodes a protein associated with the mitotic spindle apparatus. The encoded protein may be involved in the ... ADDITIONAL NAMES: DEEPEST, MAP126, hMAP126, sperm-associated antigen 5, astrin, mitotic spindle associated protein p126, ...
The canvas or cloth was attached to a spindle at each end, and an apparatus allowed it to be cranked from one end to the other ... Krannert Art Museums panoramic painting includes the spindles and the apparatus for turning them. ...
The contributors describe how sister chromatids attach to one another and to the spindle apparatus; how the spindle ... Emergent Properties of the Metaphase Spindle. Simone Reber and Anthony A. Hyman. Chromosome Dynamics during Mitosis. Tatsuya ...
Centrioles organize the spindle apparatus on which the chromosomes move during mitosis. ...
As a result, the spindle apparatus is absent, thus preventing the alignment and separation of chromosomes during mitosis. In ...
8. The "spindle apparatus" pulls the duplicated chromosome copies apart, one copy to each end of the cell. (2n 1c at each end). ...
Spindle apparatus The structure that separates the chromosomes into the daughter cells during cell division ... Mitotic spindle A spindle-shaped structure formed of microtubules and associated proteins that is involved in the movements of ... The region of a chromosome where two sister chromatids are joined and where spindle microtubules attach during mitosis and ... The second stage of mitosis, during which the nuclear envelope fragments and the spindle microtubules attach to the ...
In binary fission, there is no involvement of the mitotic apparatus like the centrioles, mitotic spindle, centromeres, and ... Opposite to the mitotic spindle, the separation of chromosomal replication is done through the cell membrane. Additionally, ... 5.Binary fission does not involve the mitotic apparatus and sister chromatids unlike in mitosis. ...
Microtubules are the only structural constituent of the spindle apparatus required for induction of cell cleavage. J. Cell Biol ... The metaphase microtubule spindle is remodelled into the central spindle (or spindle midzone), astral microtubules, originating ... initiating cytokinesis and then become incorporated in the central spindle as `peripheral central spindle microtubules. ... Although the central spindle is perturbed in the absence of a Tum-Pbl interaction or if Tum GAP activity is altered, a ...
Iso-metric/Iso-lytic Techniques; Following an iso-metric contracture the muscle spindle/ golgi tendon apparatus(neuro-muscular ... 1. Muscle spindles that detect change in muscle fibre length & rate of change in length. Each muscle spindle is built around 3- ... Thus the major difference between the GTO and the muscle spindle is the spindle detects relative muscle length & the GTO ... Muscle spindles emit sensory nerve impulses all the time when they are stretched the rate of firing increases, when they are ...
Optical recording / reproducing apparatus provided with means for adjusting installation angle of spindle motor ... Optical pickup movement apparatus JP3592563B2 (en) * 1998-12-28. 2004-11-24. パイオニア株式会社. Skew adjustment device for optical disk ... Optical Write and Read Apparatus CN2636359Y (en) * 2003-05-24. 2004-08-25. 鸿富锦精密工业(深圳)有限公司. Optical recording/reproducing ... Height adjustment device suitable for use in an optical disk apparatus JP3009639B2 (en) 2000-02-14. Disc player with tilt ...
... and microtubules form the spindle apparatus [118].. Oocytes collected by in vivo pickup or at slaughter, ovarian tissue, ... Chen, S.U., Lien, Y.R., Chao, K.H., Ho, H.N., Yang, Y.S. and Lee, T.Y. (2003) Effects of Cryopreservation on Meiotic Spindles ... Since this stage has no spindle present, GVs are assumed to be less prone to chromosomal and microtubular damage during ... The major differences between oocytes and embryos are the plasma membrane, presence of cortical granules, and spindle formation ...
Microcephaly-associated protein WDR62 shuttles from the Golgi apparatus to the spindle poles in human neural progenitors eLife ...
... similar to the size of microtubules that form the mitotic spindle and may be incorporated into the mitotic spindle apparatus. ... Our results are the first to report disruption of the mitotic spindle by SWCNT. The nanotube bundles are ... After 24 hr of exposure to either SWCNT or vanadium pentoxide, fragmented centrosomes, multiple mitotic spindle poles, anaphase ...
Drosophila γ-tubulin small complex subunit Dgrip84 is required for structural and functional integrity of the spindle apparatus ...
  • Attachment of microtubules to chromosomes is mediated by kinetochores, which actively monitor spindle formation and prevent premature anaphase onset. (wikipedia.org)
  • The cellular spindle apparatus includes the spindle microtubules, associated proteins, which include kinesin and dynein molecular motors, condensed chromosomes, and any centrosomes or asters that may be present at the spindle poles depending on the cell type. (wikipedia.org)
  • In the wide middle portion, known as the spindle midzone, antiparallel microtubules are bundled by kinesins. (wikipedia.org)
  • At the pointed ends, known as spindle poles, microtubules are nucleated by the centrosomes in most animal cells. (wikipedia.org)
  • The dynamic lengthening and shortening of spindle microtubules, through a process known as dynamic instability determines to a large extent the shape of the mitotic spindle and promotes the proper alignment of chromosomes at the spindle midzone. (wikipedia.org)
  • Microtubule-associated proteins (MAPs) associate with microtubules at the midzone and the spindle poles to regulate their dynamics. (wikipedia.org)
  • Here we combine the first large-scale serial electron tomography of whole mitotic spindles in early C. elegans embryos with live-cell imaging to reconstruct all microtubules in 3D and identify their plus- and minus-ends. (nature.com)
  • We classify them as kinetochore (KMTs), spindle (SMTs) or astral microtubules (AMTs) according to their positions, and quantify distinct properties of each class. (nature.com)
  • Remarkably, despite the high turnover of microtubules throughout mitosis 2 , the spindle maintains its bipolar structure with the chromosomes at its center and two poles that are separated by the plane of cell division. (nature.com)
  • In all spindles, the microtubule cytoskeleton connects to chromosomes via a special class of microtubules called kinetochore microtubules (KMTs). (nature.com)
  • Eg5 is localized at the centrosomes, spindle microtubules, and intracellular bridge. (biolegend.com)
  • The region of a chromosome where two sister chromatids are joined and where spindle microtubules attach during mitosis and meiosis. (freezingblue.com)
  • The nanotube bundles are similar to the size of microtubules that form the mitotic spindle and may be incorporated into the mitotic spindle apparatus. (cdc.gov)
  • A recent study implicates the microtubule-associated protein MAST/Orbit in a surprisingly wide array of mitotic activities, ranging from maintaining mitotic spindle bipolarity to tethering chromosomes to the ends of microtubules. (elsevierpure.com)
  • Background The KMN network, a ten-subunit protein complex, mediates the interaction of kinetochores with spindle microtubules and recruits spindle assembly checkpoint (SAC) constituents to halt cells in mitosis until attainment of sister chromatid biorientation. (unimib.it)
  • However, the FtsZ protein that plays such a vital role in prokaryotic cytokinesis is structurally and functionally very similar to tubulin, the building block of the microtubules that make up the mitotic spindle fibers that are necessary for eukaryotes. (opentextbc.ca)
  • The nanotube bundles are similar to the potential of nanotubes to induce genetic damage size of microtubules that form the mitotic spindle in normal lung cells, cultured primary and immor- and may be incorporated into the mitotic spindle talized human airway epithelial cells were apparatus. (cdc.gov)
  • The centrosome duplicates and, during mitosis, separates to form the two poles of the mitotic spindle (MITOTIC SPINDLE APPARATUS). (lookformedical.com)
  • in mammals, CLASP1 and CLASP2 both contribute to proper spindle assembly and microtubule dynamics in anaphase. (wikipedia.org)
  • Here, we report that PSMA is localized to a membrane compartment in the vicinity of mitotic spindle poles and associates with the anaphase-promoting complex (APC). (nih.gov)
  • These data support a model in which Tum/RacGAP, via its interaction with Pbl, provides a critical link between the anaphase microtubule spindle and cytokinetic furrow formation in Drosophila cells. (biologists.com)
  • After 24 hr of exposure to either SWCNT or vanadium pentoxide, fragmented centrosomes, multiple mitotic spindle poles, anaphase bridges, and aneuploid chromosome number were observed. (cdc.gov)
  • SPB association is strong from mitotic commitment to early anaphase B, after which the Plo1 signal becomes very weak and finally disappears upon spindle breakdown. (kent.ac.uk)
  • Furthermore, we delve into the significant role of the mitotic spindle, the complex that serves as the catalyst for moving chromosomes during anaphase, and observe the consequential fallout in case of anaphase errors, putting emphasis on common mishaps like non-disjunction which could potentially trigger chromosomal disorders including cancer and Down syndrome. (biologyideas.com)
  • What is the role of the spindle apparatus during anaphase? (yourfastadvices.com)
  • Once all the chromosomes are aligned with sister chromatids pointing to opposite ends of the spindle, the cell enters anaphase, in which the chromatids separate and move toward their respective poles. (yourfastadvices.com)
  • A microtubule is a cellular structure, part of what is called the mitotic spindle apparatus, which normally determines cleavage direction. (brown.edu)
  • During mitosis, the spindle fibers are called the mitotic spindle. (yourfastadvices.com)
  • In this instance, a Ran GTP gradient is the main regulator of spindle microtubule organization and assembly. (wikipedia.org)
  • Opposing the action of these microtubule-stabilizing proteins are a number of microtubule-depolymerizing factors which permit the dynamic remodeling of the mitotic spindle to promote chromosome congression and attainment of bipolarity. (wikipedia.org)
  • The mitotic spindle is a dynamic microtubule-based apparatus that ensures the segregation of chromosomes during cell division. (nature.com)
  • In binary fission, there is no involvement of the mitotic apparatus like the centrioles, mitotic spindle, centromeres, and kinetochores. (differencebetween.net)
  • Acentrosomal or anastral spindles lack centrosomes or asters at the spindle poles, respectively, and occur for example during female meiosis in most animals. (wikipedia.org)
  • In toto , our results show that the connection between centrosomes and chromosomes is mediated by an anchoring into the entire spindle network and that any direct connections through KMTs are few and likely very transient. (nature.com)
  • If the role of KMTs is to mediate forces between chromosomes and spindle poles, they need to somehow connect to the centrosomes. (nature.com)
  • In this paper, we set out to identify the cytoskeletal ultrastructure in C. elegans mitotic spindles that underlies this function, and how this ultrastructure is generated, using a combination of large-scale electron tomography, light microscopy and mathematical modelling. (nature.com)
  • The encoded protein may be involved in the functional and dynamic regulation of mitotic spindles. (prosci-inc.com)
  • Spindle fibers form a protein structure that divides the genetic material in a cell. (yourfastadvices.com)
  • The centrioles also help in the formation of the spindle fibers that separate the chromosomes during cell division (mitosis). (yourfastadvices.com)
  • These spindle fibers act as guides for the alignment of the chromosomes as they separate later during the process of cell division. (yourfastadvices.com)
  • Eg5 (also known as kinesin-like protein KIF11, kinesin-related motor protein Eg5, kinesin-like spindle protein HKSP, and thyroid receptor interacting protein 5 (TRIP5)) is a 119 kD kinesin-like protein family, BimC subfamily. (biolegend.com)
  • This motor protein is required for establishing the bipolar spindle. (biolegend.com)
  • This gene encodes a protein associated with the mitotic spindle apparatus. (prosci-inc.com)
  • In cell biology, the spindle apparatus is the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells. (wikipedia.org)
  • It is referred to as the mitotic spindle during mitosis, a process that produces genetically identical daughter cells, or the meiotic spindle during meiosis, a process that produces gametes with half the number of chromosomes of the parent cell. (wikipedia.org)
  • PSMA-expressing cells prematurely degrade cyclin B and exit mitosis due to increased APC activity and incomplete inactivation of APC by the spindle assembly checkpoint. (nih.gov)
  • The spindle is necessary to equally divide the chromosomes in a parental cell into two daughter cells during both types of nuclear division: mitosis and meiosis. (yourfastadvices.com)
  • During cell division, the spindle apparatus pulls together the chromosomes into the two daughter cells. (yourfastadvices.com)
  • The key purpose of a centriole is to create spindle and aster while the division of cells takes place. (yourfastadvices.com)
  • During Cytokinesis the spindle apparatus divides and moves duplicated chromatids into the cytoplasm of the separating daughter cells. (vivadifferences.com)
  • Prokaryotic cells, on the other hand, do not undergo mitosis and therefore have no need for a mitotic spindle. (opentextbc.ca)
  • In addition to the nuclei, other key structures that are specific to muscle cells within the sarcoplasm include sarcoplasmic reticulum and the contractile apparatus made of thick and thin filaments. (medscape.com)
  • The fission yeast polo related kinase Plo1 is required to assemble the mitotic spindle, the prophase actin ring that predicts the site for cytokinesis and for septation after the completion of mitosis (Ohkura et al. (kent.ac.uk)
  • Besides chromosomes, the spindle apparatus is composed of hundreds of proteins. (wikipedia.org)
  • Spindles form a link between the cell's poles and the centromere of each chromosome. (yourfastadvices.com)
  • Gamma c motor neurons, which transmit impulses to special skeletal muscle fibres, called intrafusal fibres, part of the muscle spindle. (positivehealth.com)
  • But a small number of large sensory fibres from the muscle spindles terminate directly on the anterior motor neurons. (positivehealth.com)
  • Each muscle spindle is built around 3-10 small intrafusal muscle fibres attached to the sheaths of the surrounding extrafusal skeletal muscle fibres, the ends of which are excited by small gamma efferent motor nerve fibres. (positivehealth.com)
  • The receptor portion of the muscle spindle is located midway between its to ends where the intrafusal muscle fibres have no contractile element. (positivehealth.com)
  • Sensory fibres originate in this area and are stimulated by stretch of this mid-portion of the spindle. (positivehealth.com)
  • They help in the formation of spindle fibres that separate the chromosomes during the cell cycle. (yourfastadvices.com)
  • Our results are the first to report disruption of the mitotic spindle by SWCNT. (cdc.gov)
  • Our results are the first to tubes (SWCNT) suggest the potential to interact report disruption of the mitotic spindle by with critical biological structures. (cdc.gov)
  • Centriole helps in organizing the mitotic spindle and complete the process of cytokinesis. (yourfastadvices.com)
  • The middle part of the spindle remains active during Cytokinesis in a plant cell. (vivadifferences.com)
  • During Cytokinesis in an animal cell, spindles degenerate. (vivadifferences.com)
  • Muscle spindles emit sensory nerve impulses all the time when they are stretched the rate of firing increases, when they are shortened the rate of firing decreases. (positivehealth.com)
  • The rest are sensory in nature, although the largest sensory receptors, the neuromuscular spindles, have a motor supply of their own. (medscape.com)
  • Opposite to the mitotic spindle, the separation of chromosomal replication is done through the cell membrane. (differencebetween.net)
  • The precise timing and formation of the mitotic spindle is critical to the success of eukaryotic cell division. (opentextbc.ca)
  • When the receptor portion of the muscle spindle is stretched slowly, the number of impulses transmitted from both the primary & secondary endings increases virtually in proportion to the degree of stretch. (positivehealth.com)
  • 2006). The Drosophila γ-tubulin small complex subunit Dgrip84 is required for structural and functional integrity of the spindle apparatus . (up.pt)
  • In fungi, spindles form between spindle pole bodies embedded in the nuclear envelope, which does not break down during mitosis. (wikipedia.org)
  • And when the chromosomes are condensing to undergo mitosis, the centrioles form the areas that mitotic spindle forms from. (yourfastadvices.com)
  • However, centrioles were believed to be necessary for the formation of the mitotic spindle in the animal cell. (yourfastadvices.com)
  • The spindle apparatus is vaguely ellipsoid in cross section and tapers at the ends. (wikipedia.org)
  • The dynamic stretch reflex is caused by the potent dynamic signal transmitted via the primary endings of the muscle spindles. (positivehealth.com)
  • Krannert Art Museum's panoramic painting includes the spindles and the apparatus for turning them. (illinois.edu)
  • 7] "The Stage Apparatus which Uses the Permanent Magnet Movement Linear Motor and Air Bearing," Korean Patent 07061690, 2007. (fujipress.jp)
  • hEg5 is modified by phosphorylation on Thr927 by Cdc2 to allow association with the spindle apparatus. (biolegend.com)