Recruitment of the androgen receptor via serum response factor facilitates expression of a myogenic gene

Abstract

Androgen receptor (AR) induced precocious myogenesis in culture and myogenic specified gene activity. Increased levels of AR expression in replicating C2C12 myoblasts stimulated fusion into post-differentiated multinucleated myotubes and the appearance of skeletal α-actin transcripts, even in the absence of ligand. Furthermore, AR activated the skeletal α-actin promoter, which lacks GRE sites, in co-transfected C2C12 cells. AR co-activation of the skeletal α-actin promoter required co-expressed full-length serum response factor (SRF). In vitro, AR associated with SRF and was recruited by SRF to a α-actin promoter SRF binding site. Our data suggest that AR is capable of activating myogenic genes devoid of consensus AR binding sites via its recruitment by the myogenic enriched transcription factor, SHF. © 2005 by The American Society for Biochemistry and Molecular Biology, Inc.