title: EGR1 Functions as a Potent Repressor of MEF2 Transcriptional Activity.
abstract: The myocyte enhancer factor 2 (MEF2) transcription factor requires interactions with co-factors for precise regulation of its target genes. Our lab previously reported that the mammalian MEF2A isoform regulates the cardiomyocyte costamere, a critical muscle-specific focal adhesion complex involved in contractility, through its transcriptional control of genes encoding proteins localized to this cytoskeletal structure. To further dissect the transcriptional mechanisms of costamere gene regulation and identify potential co-regulators of MEF2A, a bioinformatics analysis of transcription factor binding sites was performed using the proximal promoter regions of selected costamere genes. One of these predicted sites belongs to the early growth response (EGR) transcription factor family. The EGR1 isoform has been shown to be involved in a number of pathways in cardiovascular homeostasis and disease, making it an intriguing candidate MEF2 coregulator to further characterize. Here, we demonstrate that EGR1 interacts with MEF2A and is a potent and specific repressor of MEF2 transcriptional activity. Furthermore, we show that costamere gene expression in cardiomyocytes is dependent on EGR1 transcriptional activity. This study identifies a mechanism by which MEF2 activity can be modulated to ensure that costamere gene expression is maintained at levels commensurate with cardiomyocyte contractile activity.
authors.affiliation: Department of Biology, Program in Cell and Molecular Biology, Boston University, Boston, Massachusetts, United States of America.
authors.forename: Yi
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Biology, Program in Cell and Molecular Biology, Boston University, Boston, Massachusetts, United States of America.
authors.forename: Cody A
authors.initials: CA
authors.lastname: Desjardins
authors.affiliation: Department of Biology, Program in Cell and Molecular Biology, Boston University, Boston, Massachusetts, United States of America.
authors.forename: Olivia
authors.initials: O
authors.lastname: Cooper
authors.affiliation: Department of Biology, Program in Cell and Molecular Biology, Boston University, Boston, Massachusetts, United States of America.
authors.forename: Akuah
authors.initials: A
authors.lastname: Kontor
authors.affiliation: Department of Biology, Program in Cell and Molecular Biology, Boston University, Boston, Massachusetts, United States of America.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Nocco
authors.affiliation: Department of Biology, Program in Cell and Molecular Biology, Boston University, Boston, Massachusetts, United States of America.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Naya
mesh_terms: D000818:Animals; D019295:Computational Biology; D051766:Early Growth Response Protein 1 / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D064326:MEF2 Transcription Factors / Q000235:genetics / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D051381:Rats; D014158:Transcription, Genetic / Q000235:genetics*; D015533:Transcriptional Activation
chemical_list: D051766:Early Growth Response Protein 1; D064326:MEF2 Transcription Factors