Satellite Cells, Skeletal Muscle
Elongated, spindle-shaped, quiescent myoblasts lying in close contact with adult skeletal muscle. They are thought to play a role in muscle repair and regeneration.
DNA, Satellite
Highly repetitive DNA sequences found in HETEROCHROMATIN, mainly near centromeres. They are composed of simple sequences (very short) (see MINISATELLITE REPEATS) repeated in tandem many times to form large blocks of sequence. Additionally, following the accumulation of mutations, these blocks of repeats have been repeated in tandem themselves. The degree of repetition is on the order of 1000 to 10 million at each locus. Loci are few, usually one or two per chromosome. They were called satellites since in density gradients, they often sediment as distinct, satellite bands separate from the bulk of genomic DNA owing to a distinct BASE COMPOSITION.
PAX7 Transcription Factor
Satellite Cells, Perineuronal
RNA, Satellite
Small, linear single-stranded RNA molecules functionally acting as molecular parasites of certain RNA plant viruses. Satellite RNAs exhibit four characteristic traits: (1) they require helper viruses to replicate; (2) they are unnecessary for the replication of helper viruses; (3) they are encapsidated in the coat protein of the helper virus; (4) they have no extensive sequence homology to the helper virus. Thus they differ from SATELLITE VIRUSES which encode their own coat protein, and from the genomic RNA; (=RNA, VIRAL); of satellite viruses. (From Maramorosch, Viroids and Satellites, 1991, p143)
Muscle Development
Developmental events leading to the formation of adult muscular system, which includes differentiation of the various types of muscle cell precursors, migration of myoblasts, activation of myogenesis and development of muscle anchorage.
MyoD Protein
A myogenic regulatory factor that controls myogenesis. Though it is not clear how its function differs from the other myogenic regulatory factors, MyoD appears to be related to fusion and terminal differentiation of the muscle cell.
Muscle, Skeletal
Satellite Communications
Muscle Fibers, Skeletal
Large, multinucleate single cells, either cylindrical or prismatic in shape, that form the basic unit of SKELETAL MUSCLE. They consist of MYOFIBRILS enclosed within and attached to the SARCOLEMMA. They are derived from the fusion of skeletal myoblasts (MYOBLASTS, SKELETAL) into a syncytium, followed by differentiation.
Satellite Viruses
Defective viruses which can multiply only by association with a helper virus which complements the defective gene. Satellite viruses may be associated with certain plant viruses, animal viruses, or bacteriophages. They differ from satellite RNA; (RNA, SATELLITE) in that satellite viruses encode their own coat protein.
Myoblasts
Myogenic Regulatory Factor 5
A SKELETAL MUSCLE-specific transcription factor that contains a basic HELIX-LOOP-HELIX MOTIF. It plays an essential role in MUSCLE DEVELOPMENT.
Myogenin
A myogenic regulatory factor that controls myogenesis. Myogenin is induced during differentiation of every skeletal muscle cell line that has been investigated, in contrast to the other myogenic regulatory factors that only appear in certain cell types.
Cardiotoxins
Agents that have a damaging effect on the HEART. Such damage can occur from ALKYLATING AGENTS; FREE RADICALS; or metabolites from OXIDATIVE STRESS and in some cases is countered by CARDIOTONIC AGENTS. Induction of LONG QT SYNDROME or TORSADES DE POINTES has been the reason for viewing some drugs as cardiotoxins.
Cell Differentiation
Myostatin
Satellite Imagery
Composition of images of EARTH or other planets from data collected during SPACE FLIGHT by remote sensing instruments onboard SPACECRAFT. The satellite sensor systems measure and record absorbed, emitted, or reflected energy across the spectra, as well as global position and time.
Mice, Inbred mdx
A strain of mice arising from a spontaneous MUTATION (mdx) in inbred C57BL mice. This mutation is X chromosome-linked and produces viable homozygous animals that lack the muscle protein DYSTROPHIN, have high serum levels of muscle ENZYMES, and possess histological lesions similar to human MUSCULAR DYSTROPHY. The histological features, linkage, and map position of mdx make these mice a worthy animal model of DUCHENNE MUSCULAR DYSTROPHY.
Muscular Atrophy
Derangement in size and number of muscle fibers occurring with aging, reduction in blood supply, or following immobilization, prolonged weightlessness, malnutrition, and particularly in denervation.
Hospitals, Satellite
Cells, Cultured
Cobra Cardiotoxin Proteins
Most abundant proteins in COBRA venom; basic polypeptides of 57 to 62 amino acids with four disulfide bonds and a molecular weight of less than 7000; causes skeletal and cardiac muscle contraction, interferes with neuromuscular and ganglionic transmission, depolarizes nerve, muscle and blood cell membranes, thus causing hemolysis.
Spacecraft
Cell Proliferation
All of the processes involved in increasing CELL NUMBER including CELL DIVISION.
Myogenic Regulatory Factors
A family of muscle-specific transcription factors which bind to DNA in control regions and thus regulate myogenesis. All members of this family contain a conserved helix-loop-helix motif which is homologous to the myc family proteins. These factors are only found in skeletal muscle. Members include the myoD protein (MYOD PROTEIN); MYOGENIN; myf-5, and myf-6 (also called MRF4 or herculin).
Cucumber Mosaic Virus Satellite
A satellite RNA (not a satellite virus) which has several types. Different cucumoviruses can act as helper viruses for different types.
Myoblasts, Skeletal
Hypertrophy
Stem Cells
Muscular Dystrophies
Muscular Dystrophy, Animal
Muscular Dystrophy, Animal: A group of genetic disorders causing progressive skeletal muscle weakness and degeneration, characterized by the lack of or defective dystrophin protein, which can also affect other organ systems such as heart and brain, occurring in various forms with different degrees of severity and age of onset, like Duchenne, Becker, Myotonic, Limb-Girdle, and Facioscapulohumeral types, among others.
Muscle Fibers, Fast-Twitch
Syndecan-3
Paired Box Transcription Factors
Cell Lineage
The developmental history of specific differentiated cell types as traced back to the original STEM CELLS in the embryo.
Mice, Inbred C57BL
Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.
Muscle Proteins
The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.
Hindlimb Suspension
Desmin
An intermediate filament protein found predominantly in smooth, skeletal, and cardiac muscle cells. Localized at the Z line. MW 50,000 to 55,000 is species dependent.
Pectoralis Muscles
The pectoralis major and pectoralis minor muscles that make up the upper and fore part of the chest in front of the AXILLA.
Hepatocyte Growth Factor
Multifunctional growth factor which regulates both cell growth and cell motility. It exerts a strong mitogenic effect on hepatocytes and primary epithelial cells. Its receptor is PROTO-ONCOGENE PROTEINS C-MET.
Cell Count
Cell Division
The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.
Immunohistochemistry
Muscle Cells
Mature contractile cells, commonly known as myocytes, that form one of three kinds of muscle. The three types of muscle cells are skeletal (MUSCLE FIBERS, SKELETAL), cardiac (MYOCYTES, CARDIAC), and smooth (MYOCYTES, SMOOTH MUSCLE). They are derived from embryonic (precursor) muscle cells called MYOBLASTS.
Syndecan-4
A ubiquitously expressed syndecan that is found in all stages of embryonic development and in most adult tissues. Syndecan-4 is found localized to focal adhesion sites in fibronectin-adherent cells and may play a role the process of CELL MIGRATION and CELL PROLIFERATION.
Aging
Myosin Heavy Chains
Cell Separation
Centromere
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.
Oculomotor Muscles
The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.
Myofibrils
The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .
Stem Cell Niche
A particular zone of tissue composed of a specialized microenvironment where stem cells are retained in a undifferentiated, self-renewable state.
Tobacco mosaic satellite virus
Dystrophin
A muscle protein localized in surface membranes which is the product of the Duchenne/Becker muscular dystrophy gene. Individuals with Duchenne muscular dystrophy usually lack dystrophin completely while those with Becker muscular dystrophy have dystrophin of an altered size. It shares features with other cytoskeletal proteins such as SPECTRIN and alpha-actinin but the precise function of dystrophin is not clear. One possible role might be to preserve the integrity and alignment of the plasma membrane to the myofibrils during muscle contraction and relaxation. MW 400 kDa.
Muscular Dystrophy, Duchenne
An X-linked recessive muscle disease caused by an inability to synthesize DYSTROPHIN, which is involved with maintaining the integrity of the sarcolemma. Muscle fibers undergo a process that features degeneration and regeneration. Clinical manifestations include proximal weakness in the first few years of life, pseudohypertrophy, cardiomyopathy (see MYOCARDIAL DISEASES), and an increased incidence of impaired mentation. Becker muscular dystrophy is a closely related condition featuring a later onset of disease (usually adolescence) and a slowly progressive course. (Adams et al., Principles of Neurology, 6th ed, p1415)
Remote Sensing Technology
Muscle Fibers, Slow-Twitch
Proto-Oncogene Proteins c-met
Cell surface protein-tyrosine kinase receptors for HEPATOCYTE GROWTH FACTOR. They consist of an extracellular alpha chain which is disulfide-linked to the transmembrane beta chain. The cytoplasmic portion contains the catalytic domain and sites critical for the regulation of kinase activity. Mutations of the gene for PROTO-ONCOGENE PROTEINS C-MET are associated with papillary renal carcinoma and other neoplasia.
Base Sequence
Insulin-Like Growth Factor I
A well-characterized basic peptide believed to be secreted by the liver and to circulate in the blood. It has growth-regulating, insulin-like, and mitogenic activities. This growth factor has a major, but not absolute, dependence on GROWTH HORMONE. It is believed to be mainly active in adults in contrast to INSULIN-LIKE GROWTH FACTOR II, which is a major fetal growth factor.
Cell Transplantation
Integrin alpha Chains
The alpha subunits of integrin heterodimers (INTEGRINS), which mediate ligand specificity. There are approximately 18 different alpha chains, exhibiting great sequence diversity; several chains are also spliced into alternative isoforms. They possess a long extracellular portion (1200 amino acids) containing a MIDAS (metal ion-dependent adhesion site) motif, and seven 60-amino acid tandem repeats, the last 4 of which form EF HAND MOTIFS. The intracellular portion is short with the exception of INTEGRIN ALPHA4.
Signal Transduction
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
Gene Expression Regulation, Developmental
Anabolic Agents
Cell Fusion
Mice, Transgenic
Ganglia, Spinal
Sensory ganglia located on the dorsal spinal roots within the vertebral column. The spinal ganglion cells are pseudounipolar. The single primary branch bifurcates sending a peripheral process to carry sensory information from the periphery and a central branch which relays that information to the spinal cord or brain.
Sarcopenia
Receptors, Purinergic P2X5
Abelmoschus
Cell Nucleus
Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Tobacco necrosis satellite virus
Notophthalmus viridescens
Bromodeoxyuridine
Gene Expression Regulation
RNA, Messenger
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Heterochromatin
Mice, Knockout
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
Molecular Sequence Data
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.
Ganglia, Sensory
Helper Viruses
Neural Cell Adhesion Molecules
Cell adhesion molecule involved in a diverse range of contact-mediated interactions among neurons, astrocytes, oligodendrocytes, and myotubes. It is widely but transiently expressed in many tissues early in embryogenesis. Four main isoforms exist, including CD56; (ANTIGENS, CD56); but there are many other variants resulting from alternative splicing and post-translational modifications. (From Pigott & Power, The Adhesion Molecule FactsBook, 1993, pp115-119)
Receptors, Notch
A family of conserved cell surface receptors that contain EPIDERMAL GROWTH FACTOR repeats in their extracellular domain and ANKYRIN repeats in their cytoplasmic domains. The cytoplasmic domain of notch receptors is released upon ligand binding and translocates to the CELL NUCLEUS where it acts as transcription factor.
Cell Cycle
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.
Asymmetric Cell Division
Unequal cell division that results in daughter cells of different sizes.
Follistatin
A broadly distributed protein that binds directly to ACTIVINS. It functions as an activin antagonist, inhibits FOLLICLE STIMULATING HORMONE secretion, regulates CELL DIFFERENTIATION, and plays an important role in embryogenesis. Follistatin is a single glycosylated polypeptide chain of approximately 37-kDa and is not a member of the inhibin family (INHIBINS). Follistatin also binds and neutralizes many members of the TRANSFORMING GROWTH FACTOR BETA family.
Microscopy, Electron
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.
Rats, Wistar
Nodose Ganglion
The inferior (caudal) ganglion of the vagus (10th cranial) nerve. The unipolar nodose ganglion cells are sensory cells with central projections to the medulla and peripheral processes traveling in various branches of the vagus nerve.
Proliferating Cell Nuclear Antigen
Nuclear antigen with a role in DNA synthesis, DNA repair, and cell cycle progression. PCNA is required for the coordinated synthesis of both leading and lagging strands at the replication fork during DNA replication. PCNA expression correlates with the proliferation activity of several malignant and non-malignant cell types.
Mitogen-Activated Protein Kinase 11
A 38-kDa mitogen-activated protein kinase that is expressed in a broad variety of cell types. It may play a role in regulating cell proliferation and TRANSCRIPTION FACTOR AP-1 dependent transcription.