Molecular biology of myogenic regulatory factors.
A family of proteins has recently been identified, each member of which has the capacity to initiate muscle differentiation in many non-muscle cell types. These factors, which include MyoD1, myogenin, myf-5 and MRF4, share homologies with each other and belong to a superfamily of Myc-related proteins. Expression of these regulatory proteins results in auto-activation and cross-activation of other members of the family and in the transcriptional activation of the markers of terminal differentiation. Sequence analysis has shown a conserved basic domain in each protein that is required for binding to specific DNA sequences of the E-box type and for myogenic activation. A conserved helix-loop-helix (HLH) domain allows homo- and heterodimerization of these muscle-specific proteins with each other and with ubiquitously expressed proteins such as the E2A gene products (E12/E47). This review describes the discovery and characterization of these muscle regulatory proteins and their actions in the context of proposed models for the determination and differentiation of muscle tissue.
Funk
W D
WD
Department of Cell Biology and Neuroscience, University of Texas Southwestern Medical Center, Dallas 75235.
Ouellette
M
M
Wright
W E
WE
D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D004247:DNA / Q000302:isolation & purification / Q000502:physiology; D005786:Gene Expression Regulation / Q000502:physiology; D006133:Growth Substances / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D009132:Muscles / Q000166:cytology*
D006133:Growth Substances; D009124:Muscle Proteins; D004247:DNA