Olson E N
Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Circ Res. 1993 Jan;72(1):1-6. doi: 10.1161/01.res.72.1.1.
The two striated muscle cell types, skeletal and cardiac muscle, express overlapping sets of muscle-specific genes. Activation of muscle-specific transcription in skeletal muscle is controlled by the MyoD family of regulatory factors, which are expressed exclusively in skeletal muscle. Members of the MyoD family share homology within a basic helix-loop-helix (HLH) motif that mediates DNA binding and dimerization and form heterodimers with widely expressed HLH proteins, referred to as E proteins. Although many of the genes that are regulated by members of the MyoD family are also expressed in cardiac muscle, known members of the MyoD family have never been detected in cardiac muscle, suggesting that cardiac myocytes either express unique cell type-specific HLH proteins or rely on a distinct regulatory strategy for activation of cardiac muscle transcription. This review will summarize current knowledge of the mechanisms through which the MyoD family activates skeletal muscle transcription and will consider potential mechanisms that may regulate gene expression in the heart.
两种横纹肌细胞类型，即骨骼肌和心肌，表达重叠的肌肉特异性基因集。骨骼肌中肌肉特异性转录的激活由MyoD调节因子家族控制，该家族仅在骨骼肌中表达。MyoD家族成员在一个基本的螺旋-环-螺旋（HLH）基序内具有同源性，该基序介导DNA结合和二聚化，并与广泛表达的HLH蛋白（称为E蛋白）形成异二聚体。尽管许多受MyoD家族成员调控的基因也在心肌中表达，但从未在心肌中检测到已知的MyoD家族成员，这表明心肌细胞要么表达独特的细胞类型特异性HLH蛋白，要么依赖于一种独特的调节策略来激活心肌转录。本综述将总结目前关于MyoD家族激活骨骼肌转录机制的知识，并将探讨可能调节心脏基因表达的潜在机制。
