Regulation of muscle regulatory factors by DNA-binding, interacting proteins, and post-transcriptional modifications

Skeletal muscle differentiation is influenced by multiple pathways, which r egulate the activity of myogenic regulatory factors (MRFs)-the myogenic bas ic helix-loop-helix proteins and the MEF2-family members-in positive or neg ative ways. Here we wi II review and discuss the network of signals that re gulate MRF function during myocyte proliferation, differentiation, and post -mitotic growth. Elucidating the mechanisms governing muscle-specific trans cription will provide important insight in better understanding the embryon ic development of muscle at the molecular level and will have important imp lications in setting out strategies aimed at muscle regeneration. Since the activity of MRFs are compromised in tumors of myogenic derivation-the rhab domyosarcomas-the studies summarized in this review can provide a useful to ol to uncover the molecular basis underlying the formation of these rumors. (C) 2000 Wiley-Liss, Inc.