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Updated: Jun 13, 2026
10:28
Repressing Gene Transcription by Redirecting Cellular Machinery with Chemical Epigenetic Modifiers
Published on: September 20, 2018
Myogenic microRNA expression requires ATP-dependent chromatin remodeling enzyme function
Chandrashekara Mallappa1, Brian T Nasipak, Letitiah Etheridge
1Department of Cell Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
Molecular and Cellular Biology
|April 28, 2010
Summary
Knockdown of Brg1 chromatin remodeler in zebrafish stunts tail growth and alters muscle structure. Brg1 is crucial for regulating microRNA expression, impacting muscle development.
Area of Science:
- Muscle development and regeneration
- Chromatin remodeling
- MicroRNA gene regulation
Background:
- SWI/SNF chromatin remodeling enzymes play roles in gene regulation.
- MicroRNAs are critical regulators of cellular differentiation, including myogenesis.
- The specific role of ATP-dependent chromatin remodelers in microRNA regulation during myogenesis is not fully understood.
Purpose of the Study:
- To investigate the role of the Brg1 ATPase subunit of SWI/SNF chromatin remodelers in zebrafish development and myogenesis.
- To determine the impact of Brg1 on myogenic microRNA expression and chromatin accessibility.
- To elucidate the regulatory relationship between Brg1, MyoD, and myogenic microRNAs.
Main Methods:
- Knockdown of Brg1 in developing zebrafish.
- Ex vivo differentiation of Brg1 conditional myoblasts.
- Analysis of sarcomeric actin organization and tail formation.
- Chromatin immunoprecipitation (ChIP) assays to assess Brg1 and MyoD binding.
- Assessment of chromatin accessibility and microRNA expression.
Main Results:
- Brg1 knockdown in zebrafish resulted in stunted tail formation and altered sarcomeric actin organization, mimicking Dicer or myogenic microRNA loss.
- Myogenic microRNA expression and myoblast differentiation were inhibited in Brg1-deficient myoblasts.
- Brg1 binding upstream of myogenic microRNAs correlated with MyoD binding and chromatin accessibility in vivo and in vitro.
- Brg1 was essential for maintaining chromatin accessibility and microRNA expression during myogenesis.
Conclusions:
- ATP-dependent chromatin remodelers, specifically Brg1, are implicated in the regulation of myogenic microRNA genes.
- Brg1 plays a critical role in controlling chromatin accessibility at myogenic microRNA loci.
- These findings highlight a novel mechanism linking chromatin remodeling to microRNA-mediated gene regulation in muscle development.
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