Myogenesis provides a model system to examine the control of contractile protein biosynthesis. Alpha Actin is found only in skeletal muscle, while other polymorphic forms of actin are found in a large variety of nonmuscle cell types. Nonmuscle actins are associated with cell cytoskeleton, movement, division, adhesion, shape and excretion. In the case of muscle Alpha actin, this p rotein appears only after myoblast fusion and the controlling factor is unknown. The major objective is to examine the mechanisms(s) involved with the selective expression of the skeletal muscle Alpha actin structural gene from all other members within the actin multigene family, during muscle development in culture. Two dependent lines of investigation will be employed. First, the actin structural genes within the chicken genome will be isolated, identified, and then characterized for homologous and nonhomologous nucleic acid sequences in comparison to the muscle Alpha actin gene. It will be necessary to subclone genomic actin sequences into plasmid vectors and then restriction endonuclease map the actin genes. The conserved coding region, transcriptional oreintation and location of intervening sequence in the actin genes will be determined. The Alpha actin structural gene will be nucleic acid sequenced as well as portions of the other actin genes. Second, specific actin gene sequences will be used as hybridization probes to investigate transcriptional regulation of the Alpha actin structural gene product during myogenesis. Initial transcription rates and stability of Alpha actin mRNA will be determined by pulse chase analysis. The role of DNA modification and conformation will be examined as correlates to gene activity. Finally, the long range goal will be to identify potential regulatory sequences in the Alpha actin gene which might allow for its selective expression in muscle. In this way, it might be possible to understand the defects in gene regulation in inherited neuromuscular diseases.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL038401-12
Application #
3354625
Study Section
Molecular Cytology Study Section (CTY)
Project Start
1987-01-08
Project End
1991-12-31
Budget Start
1990-01-01
Budget End
1990-12-31
Support Year
12
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Type
Schools of Medicine
DUNS #
074615394
City
Houston
State
TX
Country
United States
Zip Code
77030
Moss, J B; Olson, E N; Schwartz, R J (1996) The myogenic regulatory factor MRF4 represses the cardiac alpha-actin promoter through a negative-acting N-terminal protein domain. J Biol Chem 271:31688-94
Moss, J B; McQuinn, T C; Schwartz, R J (1994) The avian cardiac alpha-actin promoter is regulated through a pair of complex elements composed of E boxes and serum response elements that bind both positive- and negative-acting factors. J Biol Chem 269:12731-40
Lee, T C; Shi, Y; Schwartz, R J (1992) Displacement of BrdUrd-induced YY1 by serum response factor activates skeletal alpha-actin transcription in embryonic myoblasts. Proc Natl Acad Sci U S A 89:9814-8
Parker, T G; Chow, K L; Schwartz, R J et al. (1992) Positive and negative control of the skeletal alpha-actin promoter in cardiac muscle. A proximal serum response element is sufficient for induction by basic fibroblast growth factor (FGF) but not for inhibition by acidic FGF. J Biol Chem 267:3343-50
Blank, R S; McQuinn, T C; Yin, K C et al. (1992) Elements of the smooth muscle alpha-actin promoter required in cis for transcriptional activation in smooth muscle. Evidence for cell type-specific regulation. J Biol Chem 267:984-9
Lee, T C; Chow, K L; Fang, P et al. (1991) Activation of skeletal alpha-actin gene transcription: the cooperative formation of serum response factor-binding complexes over positive cis-acting promoter serum response elements displaces a negative-acting nuclear factor enriched in replicating myobla Mol Cell Biol 11:5090-100
Zhu, Y Y; Schwartz, R J; Crow, M T (1991) Phorbol esters selectively downregulate contractile protein gene expression in terminally differentiated myotubes through transcriptional repression and message destabilization. J Cell Biol 115:745-54
Chow, K L; Hogan, M E; Schwartz, R J (1991) Phased cis-acting promoter elements interact at short distances to direct avian skeletal alpha-actin gene transcription. Proc Natl Acad Sci U S A 88:1301-5
French, B A; Chow, K L; Olson, E N et al. (1991) Heterodimers of myogenic helix-loop-helix regulatory factors and E12 bind a complex element governing myogenic induction of the avian cardiac alpha-actin promoter. Mol Cell Biol 11:2439-50
French, B A; Bergsma, D J; Schwartz, R J (1990) Analysis of a CR1 (chicken repeat) sequence flanking the 5' end of the gene encoding alpha-skeletal actin. Gene 88:173-80

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