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DNA-binding site for two skeletal actin promoter factors is important for expression in muscle cells
1Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Molecular and Cellular Biology
|April 1, 1988
Summary
Nuclear factors binding to the chicken skeletal actin promoter are crucial for muscle cell expression. Mutations disrupting this binding significantly reduce gene activity in muscle but not in nonmuscle cells.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The regulation of gene expression in differentiated cells is complex.
- Specific DNA sequences and protein factors control tissue-specific gene activity.
Purpose of the Study:
- To investigate the role of a specific binding site in the chicken skeletal actin promoter.
- To determine the contribution of this site to muscle-specific gene expression and repression in nonmuscle cells.
Main Methods:
- Analysis of nuclear factor binding to the chicken skeletal actin promoter.
- Site-directed mutagenesis of the identified footprint sequence.
- Reporter gene assays in transfected skeletal muscle and nonmuscle cells.
Main Results:
- Two nuclear factors were found to bind to the same site in the promoter.
- Mutations eliminating binding reduced skeletal actin expression in muscle cells by 25-50 fold.
- These mutations did not significantly alter the low expression observed in nonmuscle cells.
Conclusions:
- The identified factor-binding site plays a significant role in activating gene expression in skeletal muscle cells.
- This regulatory site is not solely responsible for repressing gene expression in nonmuscle cells.