Myogenic Differentiation (MyoD)

MyoD is a protein with a key role in regulating muscle differentiation. MyoD belongs to a family of proteins known as myogenic regulatory factors (MRFs). These bHLH (basic helix loop helix) transcription factors act sequentially in myogenic differentiation. MRF family members include MyoD, Myf5, myogenin, and MRF4 (Myf6). MYOD is directly acetylated by PCAF at evolutionarily conserved lysines. Acetylated MYOD displayed an increased affinity for its DNA target. Conservative substitutions of acetylated lysines with nonacetylatable arginines impaired the ability of MYOD to stimulate transcription and to induce conversion, indicating that acetylation of MYOD is functionally critical. MYOD mRNA was also downregulated by TNF and IFNG expression in mouse muscle in vivo.