Regulation of tropomyosin gene expression during myogenesis
In skeletal muscle, tropomyosin has a critical role in transduction of calcium-induced contraction. Presently, little is known about the regulation of tropomyosin gene expression during myogenesis. In the present study, qualitative and quantitative changes in the nucleic acid populations of differentiating chicken embryo muscle cells in culture have been examined. Total nucleic acid content per nucleus increased about fivefold in fully developed myotubes as compared to mononucleated myoblasts. The contribution of deoxyribonucleic acid to the total nucleic acid population decreased from 24% in myoblasts to 5% of total nucleic acid in myotubes. Concomitant with the decrement in deoxyribonucleic acid contribution to total nucleic acid was an increase in polyadenylated ribonucleic acid (RNA) content per cell which reached levels in myotubes that were 17-fold higher than those of myoblasts. Specific changes in the RNA population during myogenesis were further investigated by quantitation of the synthetic capacity (messenger RNA levels) per cell for ..cap alpha..- and ..beta..-tropomyosin. Cell-free translation and immunoprecipitation demonstrated an approximately 40-fold increase in messenger RNA levels per nucleus for ..cap alpha..- and ..beta..-tropomyosin after fusion in the terminally differentiated myotubes. Indirect immunofluorescence with affinity-purified tropomyosin antibodies demonstrated the presence of tropomyosin-containing filaments in cells throughout myogenesis. Thus, the tropomyosin genes are constitutively expressed during muscle differentiation through the production of tropomyosin messenger RNA and translation into tropomyosin protein.
- Research Organization:
- Dept. of Microbiology, College of Medicine, Univ. of California-Irvine, Irvine, CA 92717
- OSTI ID:
- 5887856
- Journal Information:
- Mol. Cell. Biol.; (United States), Vol. 1:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CELL DIFFERENTIATION
MOLECULAR BIOLOGY
MYOBLASTS
TROPOMYOSIN
ANTIGEN-ANTIBODY REACTIONS
CLASSIFICATION
ELECTROPHYSIOLOGY
FLUORESCENCE
GENE REGULATION
CALCIUM IONS
CELL CULTURES
CHICKENS
DNA
ELECTRIC CONDUCTIVITY
EMBRYOS
GENES
MESSENGER-RNA
MICROTUBULES
RNA PROCESSING
TRANSCRIPTION
ANIMALS
BIRDS
CELL CONSTITUENTS
CHARGED PARTICLES
ELECTRICAL PROPERTIES
FOWL
IONS
LUMINESCENCE
MUSCLES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
PHYSIOLOGY
RNA
VERTEBRATES
550800* - Morphology
550200 - Biochemistry