GSBS Student Publications

Title

Myogenin and the SWI/SNF ATPase Brg1 maintain myogenic gene expression at different stages of skeletal myogenesis

Student Author(s)

Concetta G. A. Marfella

GSBS Program

Cell Biology

UMMS Affiliation

Department of Cell Biology

Date

3-2-2007

Document Type

Article

Medical Subject Headings

Animals; Cell Line; Chromosomal Proteins, Non-Histone; DNA Helicases; Embryo, Mammalian; *Gene Expression Regulation, Developmental; Mice; Muscle Development; Muscle, Skeletal; MyoD Protein; Myogenin; Nuclear Proteins; Promoter Regions (Genetics); Transcription Factors

Disciplines

Cell Biology | Life Sciences | Medicine and Health Sciences

Abstract

Many studies have examined transcriptional regulation during the initiation of skeletal muscle differentiation; however, there is less information regarding transcriptional control during adult myogenesis and during the maintenance of the differentiated state. MyoD and the mammalian SWI/SNF chromatin-remodeling enzymes containing the Brg1 ATPase are necessary to induce myogenesis in cell culture models and in developing embryonic tissue, whereas myogenin and Brg1 are critical for the expression of the late genes that induce terminal muscle differentiation. Here, we demonstrate that myogenin also binds to its own promoter during the late stages of embryonic muscle development. As is the case during embryonic myogenesis, MyoD and Brg1 co-localize to the myogenin promoter in primary adult muscle satellite cells. However, in mature myofibers, myogenin and Brg1 are preferentially co-localized to the myogenin promoter. Thus, the myogenin promoter is occupied by different myogenic factors at different times of myogenesis. The relevance of myogenin in the continued expression from its own promoter is demonstrated in culture, where we show that myogenin, in the absence of MyoD, is capable of maintaining its own expression by recruiting the Brg1 ATPase to modify promoter chromatin structure and facilitate myogenin expression. Finally, we utilized in vivo electroporation to demonstrate that Brg1 is required for the continued production of the myogenin protein in newborn skeletal muscle tissue. These findings strongly suggest that the skeletal muscle phenotype is maintained by myogenin and the continuous activity of Brg1-based SWI/SNF chromatin-remodeling enzymes.

Rights and Permissions

Citation: J Biol Chem. 2007 Mar 2;282(9):6564-70. Epub 2006 Dec 27. Link to article on publisher's site

Related Resources

Link to article in PubMed

Journal Title

The Journal of biological chemistry

PubMed ID

17194702