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Spindle ApparatusMeiosisMicrotubulesOocytesMetaphaseMuscle SpindlesMicrotubule-Organizing CenterKinesinTubulinChromosome SegregationCentrosomeMicroscopy, PolarizationMitosisChromosomesAnaphasePolar BodiesMicrotubule-Associated ProteinsKinetochoresNocodazoleOvumMicrotubule ProteinsFertilizationOogenesisProphaseCell ExtractsNondisjunction, GeneticDyneinsMicroscopy, ConfocalCell Cycle ProteinsXenopus ProteinsZygoteParthenogenesisAurora KinasesMicroscopy, FluorescenceCaenorhabditis elegans ProteinsCaenorhabditis elegansCleavage Stage, OvumTubulin ModulatorsCell PolarityAneuploidySpermatocytesBivalviaMiosisDrosophila ProteinsSperm Injections, IntracytoplasmicCytoskeletonMad2 ProteinsMutationEmbryo, NonmammalianCryopreservationFertilization in VitroNuclear ProteinsCentromereXenopus laevisCell NucleusDrosophila melanogasterNuclear Matrix-Associated ProteinsProtein-Serine-Threonine KinasesXenopusCell CycleDrosophilaFluorescent Antibody TechniqueEmbryo, MammalianM Phase Cell Cycle CheckpointsCDC2 Protein KinaseChromatinTelophaseCytoplasmActin CytoskeletonAdenosine TriphosphatasesMicroinjectionsCytokinesisSpermatozoaModels, BiologicalPaclitaxelSperm-Ovum InteractionsGreen Fluorescent ProteinsActinsMolecular Sequence DataMotor Neurons, GammaPrometaphaseCulture TechniquesEmbryonic DevelopmentCentriolesAmino Acid SequenceSpermatogenesisHeLa CellsSaccharomyces cerevisiae ProteinsMice, Inbred StrainsCdc20 ProteinsPhosphorylationCells, Culturedran GTP-Binding ProteinBirefringenceAurora Kinase BSaccharomyces cerevisiaeGenes, cdcChromosomal Proteins, Non-HistoneSchizosaccharomycesImmunohistochemistry
ChromosomesOocytesApparatusMicrotubulesProphaseMeiosisMicrotubuleFission yeastCheckpointKinetochoreMitosisOocyte meioticMitotic spindlesPolar body extrusionProgressionMaturationPolesProteinsPrometaphaseMaternalElongationCytoplasmBirefringenceDynamicsNucleiMammalianArrestStructuralDivisionFormationComplexStagesElectron
Chromosomes25
  • The two meiotic divisions, known as Meiosis I and Meiosis II, may also include various genetic recombination events between homologous chromosomes. (wikipedia.org)
  • metaphase The stage of mitosis and meiosis that occurs after prometaphase and before anaphase, during which the centromeres of the replicated chromosomes align along the equator of the cell, with each kinetochore attached to the mitotic spindle. (wikipedia.org)
  • To segregate the chromosomes faithfully during cell division, cells assemble a spindle that captures the kinetochores and pulls them towards opposite poles. (divide-eunetwork.org)
  • Interactions of the meiotic spindle with mitotic chromosomes in GV mouse oocytes. (ox.ac.uk)
  • This research employed a unique model in the mouse, mitotic chromosomes transferred to meiotic cytoplasts to investigate whether a meiotic oocyte's microtubule apparatus can effectively separate mitotic metaphase chromosomes, and whether a spindle checkpoint exists during its division. (ox.ac.uk)
  • When mitotic chromosomes were transferred into enucleated or intact mouse GV oocytes, the first bipolar meiotic spindles were established and the reconstructed oocytes were able to extrude polar bodies. (ox.ac.uk)
  • The data indicate that a spindle checkpoint, providing surveillance of misaligned chromosomes, was overridden or compromised by the incompatibility between somatic chromosomes and meiotic spindles during the first meiotic division. (ox.ac.uk)
  • Immunostaining and immunoblotting analysis showed that CK2 was constantly expressed and located on the chromosomes during the entire oocyte meiotic maturation. (biomedcentral.com)
  • Thus, the unique mode of spindle formation in Xenos oocytes cannot be used to support the hypothesis that chromosomes (kinetochores) induce the polymerization of their associated MTs. (silverchair.com)
  • Prior to the first meiotic division, homologous chromosomes pair, synapse, and recombine to ensure their proper disjunction at anaphase I. Additionally, telomeres tethered at the nuclear envelope cluster in the bouquet configuration where they are subjected to dramatic pulling forces acting from outside of the nucleus. (biorxiv.org)
  • Surprisingly, the nup2Δ ndj1Δ double mutant failed to segregate chromosomes, even though the meiotic program continued. (biorxiv.org)
  • A . Schematic of the bouquet configuration of chromosomes during meiotic prophase I. The spatial arrangement of chromosomes with telomeres clustered and attached at the inner nuclear membrane is shown. (biorxiv.org)
  • The mitotic spindle ensures the faithful segregation of chromosomes. (nature.com)
  • 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)
  • The mitotic spindle is a dynamic microtubule-based apparatus that ensures the segregation of chromosomes during cell division. (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)
  • If the role of KMTs is to mediate forces between chromosomes and spindle poles, they need to somehow connect to the centrosomes. (nature.com)
  • f ) Confocal microscopy detail of the meiotic spindle structure in an oocyte reconstructed by MST at a high magnification (600x) showing a normal barrel shape spindle (green) and aligned chromosomes in the metaphase plate (blue). (elifesciences.org)
  • In the late prophase which is also called prometaphase, the mitotic spindle starts to organize the chromosomes. (vedantu.com)
  • At the end of the prophase, the mitotic spindle grows, and some microtubules start to capture and organize chromosomes. (vedantu.com)
  • Metaphase starts when the mitotic spindle organizes all chromosomes and lines them up in the middle of the cell to divide. (vedantu.com)
  • Microtubules are important for the formation of meiotic spindles to support right segregations of chromosomes. (styleslicker.com)
  • The second meiotic division begins with half of the original number of chromosomes. (styleslicker.com)
  • In a mother carrying such mutations, one technique that is used to reduce the chances of disease transmission is spindle-chromosomal complex transfer (SCCT), in which the nuclear chromosomes are removed from an unfertilized egg while they are arranged along a structure called the spindle complex, and transferred to a donor egg cell that has healthy mitochondria. (eurekalert.org)
Oocytes13
  • In addition, we found that spindle/chromosome structure was disrupted in CK2-inhibited oocytes due to the weakened microtubule stability, which is a major cause resulting in the activation of SAC. (biomedcentral.com)
  • Last, we found that the level DNA damage as assessed by γH2A.X staining was considerably elevated when CK2 was inhibited, suggesting that DNA damage might be another critical factor leading to the SAC activation and meiotic failure of oocytes. (biomedcentral.com)
  • We also employed the CK2-specific inhibitor CX-4945 to validate the effect of CK2 activity on the polar body extrusion, spindle assembly, microtubule stability and DNA damage level in porcine oocytes. (biomedcentral.com)
  • Intranuclear membranes and the formation of the first meiotic spindle in Xenos peckii (Acroschismus wheeleri) oocytes. (silverchair.com)
  • The ultrastructure of spindle formation during the first meiotic division in oocytes of the Strepsipteran insect Xenos peckii Kirby (Acroschismus wheeleri Pierce) was examined in serial thick (0.25-micron) and thin sections. (silverchair.com)
  • Mammalian oocytes are maintained in meiotic prophase arrest for a very long time-months in mice, years in humans. (wikipedia.org)
  • Maternal spindle transfer (MST) between sibling fresh B6CBAF1 mouse oocytes does not impair embryo development. (elifesciences.org)
  • d ) Spindle being exposed to inactivated Sendai virus HVJ-E. ( e-g ) Reconstruction of enucleated oocytes and confirmation with polarized light ( h-i ). (elifesciences.org)
  • Representative immunofluorescence images of B6CBAF1 strain fresh (left) or vitrified (right) oocytes that have been non-manipulated (control) or used as spindle (sp) donors for MST procedures. (elifesciences.org)
  • Meiotic spindle transfer between NZB/OlaHsd and B6CBAF1 oocytes. (elifesciences.org)
  • c ) Representative blastocyst images from NZB oocytes fertilized by ICSI and cultured for 96 hr (left) or MST embryos where NZB spindle was transferred into B6 strain cytoplasts (right) fertilized by ICSI and cultured for 96 hr. (elifesciences.org)
  • These mutations cause a range of folding defects in vitro, different degrees of microtubule disruption upon expression in cultured cells and interfere to varying extents in the proper assembly of the meiotic spindle in mouse oocytes. (bmj.com)
  • Surprisingly, oocytes from patients harbouring homozygous TUBB8 mutations that in either case preclude the expression of a functional TUBB8 polypeptide nonetheless contained identifiable spindles. (bmj.com)
Apparatus4
  • meiotic spindle See spindle apparatus. (wikipedia.org)
  • Microtubules (MTs) were found associated with membranes of the meiotic apparatus only after the nuclear envelope had broken down. (silverchair.com)
  • The fully formed metaphase arrested Xenos oocyte meiotic apparatus contained an abundance of membranes and had diffuse poles that lacked distinct polar MT organizing centers. (silverchair.com)
  • Our observation that MTs appeared in association with and parallel to tubular membrane components of the Xenos meiotic apparatus after these membranes became oriented with respect to the tetrads, is consistent with the notion that membranes associated with the spindle determine the orientation of spindle MTs and also play a part in regulating their formation. (silverchair.com)
Microtubules7
Prophase2
  • 39:157-197)--actually form during late prophase, lack MTs, and are therefore not complete miniature bipolar spindles, as had been commonly assumed. (silverchair.com)
  • The events of meiotic prophase follow a specialized round of DNA replication when the meiotic chromosome axis is formed. (biorxiv.org)
Meiosis5
  • Oocyte meiosis, important to all animal life cycles yet unlike all other instances of animal cell division, occurs completely without the aid of spindle -coordinating centrosomes . (wikipedia.org)
  • Meiosis begins with DNA replication and meiotic crossing over. (wikipedia.org)
  • Spindle pole bodies (SPBs) provide a structural basis for genome inheritance and spore formation during meiosis in yeast. (rupress.org)
  • The prospore membrane is a double-membraned structure that extends from the cytoplasmic face of the spindle pole bodies to encompass the spindle pole bodies and the four nuclear lobes that are formed during meiosis. (yeastgenome.org)
  • Spindle endoplasmic reticulum (ER) in meiosis II was found to be derived largely from invaginations and evaginations of the nuclear envelope. (vuw.ac.nz)
Microtubule4
  • Proper spindle function requires correct interplay between microtubule motors and non-motor proteins. (divide-eunetwork.org)
  • We identified the second kinesin-14 family protein Klp2 and microtubule dynamics as factors necessary for proper meiotic spindle assembly. (divide-eunetwork.org)
  • The role of microtubule pivoting in formation of complex structures such as microtubule bundles and mitotic spindles. (irb.hr)
  • Active mitotic translation occurs on X. laevis meiotic spindles, and a subset of microtubule-bound mRNAs (MT-mRNAs) associate with polyribosomes. (escholarship.org)
Fission yeast2
  • Here, we compared mitotic and meiotic spindles in fission yeast. (divide-eunetwork.org)
  • This work defines the differences between mitotic and meiotic spindles in fission yeast Schizosaccharomyces pombe, and provides prospect for future comparative studies.This article has an associated First Person interview with the first author of the paper. (divide-eunetwork.org)
Checkpoint3
  • During mitosis, a spindle checkpoint detects chromosome misalignment and halts the cell cycle progression. (ox.ac.uk)
  • We report that CK2 is essential for porcine oocyte meiotic maturation by regulating spindle assembly checkpoint (SAC). (biomedcentral.com)
  • The spindle checkpoint ensures that the sister chromatids are split equally into two daughter cells. (vedantu.com)
Kinetochore2
  • The kinetochore region in the first meiotic division consisted of two closely appressed, but structurally (and functionally) distinct, sister kinetochores. (vuw.ac.nz)
  • The fine structure of the spindle and diffuse kinetochore. (karger.com)
Mitosis1
  • Indeed, that such forces exist in C. elegans is evidenced by the maintenance of half-spindle lengths throughout mitosis 5 and in many perturbations experiments. (nature.com)
Oocyte meiotic1
  • In the current study, we explored the functional roles of CK2 on the porcine oocyte meiotic maturation. (biomedcentral.com)
Mitotic spindles1
  • 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)
Polar body extrusion1
  • The spindle formation and polar body extrusion suggest that the first meiotic spindle was functional, and the chromosome misalignment did not prevent the onset of anaphase. (ox.ac.uk)
Progression2
  • We examined the localization and expression patterns of CK2 in the various developmental stages of meiotic progression. (biomedcentral.com)
  • Initially the arrest is due to lack of sufficient cell cycle proteins to allow meiotic progression. (wikipedia.org)
Maturation1
  • Our findings demonstrate that CK2 promotes the porcine oocyte maturation by ensuring normal spindle assembly and DNA damage repair. (biomedcentral.com)
Poles2
  • The mitotic spindle grows between the centrosomes of the cell as they move towards different poles. (vedantu.com)
  • The centrosomes that had been duplicated during interphase I move away from each other toward opposite poles and new spindles are fashioned. (styleslicker.com)
Proteins3
  • Here we identified Nup2 in a pool of enriched proteins that co-purify with tagged Ndj1 from meiotic cell extracts. (biorxiv.org)
  • However, as the oocyte grows, these proteins are synthesized, and meiotic arrest becomes dependent on cyclic AMP . (wikipedia.org)
  • Occupational exposure limits with proteins such as topoisomerase inhibitors, and mitotic and meiotic spindle poisons. (cdc.gov)
Prometaphase3
  • From these observations we conclude that the apparent individual chromosomal spindles--seen in the light microscope to form around each Xenos tetrad during "intranuclear prometaphase" (Hughes-Schrader, S., 1924, J. Morphol. (silverchair.com)
  • Growth of existing spindle ER was proposed to account for the doubling in the amount of ER observed between interphase and prometaphase II. (vuw.ac.nz)
  • Randomly oriented elements of ER, in early prometaphase II spindles may become passively aligned along the interpolar axis and then actively transported polewards at later stages of prometaphase II and metaphase II. (vuw.ac.nz)
Maternal2
  • Unfortunately, some disease-carrying maternal mitochondria often get swept up along with the spindle complex. (eurekalert.org)
  • 2023) Significant decrease of maternal mitochondria carryover using optimized spindle-chromosomal complex transfer. (eurekalert.org)
Elongation3
  • We show that, even though mitotic and meiotic spindles underwent the typical three phases of spindle elongation, they have distinct features. (divide-eunetwork.org)
  • The extent of spindle elongation in Tradescantia could not be determined. (vuw.ac.nz)
  • No relationship was found between nkMT distribution and spindle elongation, and the several different nkMT distributions which have been reported for other cell types may be variations on a structural theme. (vuw.ac.nz)
Cytoplasm3
  • Located in cytoplasm and meiotic spindle. (nih.gov)
  • Second, after extracting the spindle-chromosomal complex from the egg, they transferred it into an even narrower-diameter tube (12 micrometers for mice, 10 micrometers for humans), in order to begin to squeeze cytoplasm away from the complex. (eurekalert.org)
  • It helps isolate the meiotic nuclei from the cytoplasm during spore formation and serves as a foundation for the formation of the spore walls. (yeastgenome.org)
Birefringence2
Dynamics2
  • Defects in spindle assembly or changes in spindle dynamics are associated with diseases, such as cancer or developmental disorders. (divide-eunetwork.org)
  • Cytoskeletal dynamics and spindle assembly during cell division. (irb.hr)
Nuclei1
  • then, at the first meiotic division, they are partitioned into completely different nuclei. (styleslicker.com)
Mammalian1
  • Mammalian Emi2 mediates cytostatic arrest and transduces the signal for meiotic exit via Cdc20. (nih.gov)
Arrest2
  • Maintenance of meiotic arrest also depends on the presence of a multilayered complex of cells, known as a follicle, that surrounds the oocyte. (wikipedia.org)
  • In the oocyte, cyclic GMP prevents the breakdown of cyclic AMP by the phosphodiesterase PDE3, and thus maintains meiotic arrest. (wikipedia.org)
Structural1
  • This is regulated by the concentration of three structural meiotic SPB components, which is dependent on available amounts of carbon source. (rupress.org)
Division1
  • and negative regulation of meiotic nuclear division. (nih.gov)
Formation2
  • The roles of tubulins in caenorhabditis elegans meiotic and mitotic spindle formation (Doctoral thesis, University of Calgary, Calgary, Canada). (ucalgary.ca)
  • These components are known to participate in the formation of many cellular structures, such as the dynamic asters found in mitotic and meiotic spindles 3 , 4 . (sciforums.com)
Complex1
  • First, they transferred sperm into the egg cell before removing the spindle-chromosomal complex, rather than waiting until after removal, since previous studies have shown that manipulation itself can prematurely activate the meiotic process, which is normally arrested until fertilization. (eurekalert.org)
Stages1
  • This technique was developed to permit the preselection of PMCs at known meiotic stages, for subsequent EM examination. (vuw.ac.nz)
Electron1
  • Reliable techniques for the living cell culture and correlative light and electron microscopy (EM) of meiotic pollen mother cells (PMCs) of Iris spuria, Allium triquetrum and Tradescantia flumenensis are described in detail. (vuw.ac.nz)