Disease relevance of MYOG

• Myogenin mRNA is elevated during rapid, slow, and maintenance phases of stretch-induced hypertrophy in chicken slow-tonic muscle [1].

High impact information on MYOG

• The application of RA on primary cultures of embryonic somites, limb buds, and neonatal limbs inhibited myogenic differentiation in a dose-dependent way as indicated by the repression of: (a) myotube formation, (b) myosin heavy chain protein accumulation, (c) myosin light chain (MLC) 1/3, alpha sk-actin and myogenic factor transcript expression [2].
• Specific mutation of the Sp1 site markedly affects transactivation by CMD1 or myogenin [3].
• MyoD and myogenin act on the chicken myosin light-chain 1 gene as distinct transcriptional factors [4].
• Expression of MyoD, myogenin, MRF4, and Myf-5 converts nonmuscle cells to muscle cells [4].
• The activation by CMD1 or c-myogenin (chicken MyoD or myogenin, respectively) was dependent on the existence of a muscle-specific regulatory region located from positions -2096 to -1743 [4].

Biological context of MYOG

• The myogenic basic helix-loop-helix (bHLH) transcription factors, Myf5, MyoD, myogenin and MRF4, are unique in their ability to direct a program of specific gene transcription leading to skeletal muscle phenotype [5].
• In vitro protein/DNA interaction studies suggest that CaM kinase II inhibits binding of the myogenic factor, myogenin, to the delta-promoter 47-base pair activity-dependent enhancer [6].
• Whereas myogenin mRNA and protein levels were down-regulated by chloramphenicol treatment, they were up-regulated by p43 overexpression, in a positive relationship with the expression level of the transgene [7].
• Interaction of the myogenic determination factor myogenin with E12 and a DNA target: mechanism and kinetics [8].
• Satellite cell differentiation was marked by morphological changes as well as by increased sarcomeric myogenin content and creatine kinase activity and changes in the expression of the regulatory muscle-specific genes, MyoD and myogenin [9].

Anatomical context of MYOG

• The differentiation defective myoblasts do not express myosin heavy chain but the relative amounts of myogenin, desmin and troponin proteins do not differ from controls [10].
• A survey of the expression of myogenic genes showed that the myogenic markers Myf5, MyoD and myogenin were expressed in branchial arch muscle, but at comparatively late stages compared with their expression in the somites [11].
• We report that chicken embryos, after surgical removal of the neural tube at the level of the unsegmented paraxial mesoderm, start to develop myotomal cells that express transcripts for the muscle-specific regulators MyoD and myogenin [12].
• Myogenin dephosphorylation is also observed upon incubation of myotubes with GF109203X, a pharmacological agent which specifically inhibits PKC activity [13].
• Myogenin and CMD1, the chicken homologue of MyoD, transactivate the promoter of the alpha-subunit of the acetylcholine receptor (AChR) in chicken fibroblasts [14].

Associations of MYOG with chemical compounds

• We also found that myogenin or CMD1 overexpression in chloramphenicol-treated myoblasts did not restore differentiation, thus indicating that an alteration in mitochondrial activity interferes with the ability of myogenic factors to induce terminal differentiation [7].
• We found that relative to the wild-type receptor, enhanced binding to Grb2 further increases the incorporation of bromodeoxyuridine and the expression of Twist, while decreasing that of p27(Kip1) and myogenin [15].
• Phosphorylation of myogenin in chick myotubes: regulation by electrical activity and by protein kinase C. Implications for acetylcholine receptor gene expression [13].
• Myogenin gene activity declined rapidly (t1/2: approximately 2 min), comparable to the rate of acetylcholine receptor (AChR) gene inactivation, while other myogenic bHLH genes either lost activity more slowly (MyoD) or not at all (myf5, herculin) [16].
• We have found previously that activation of protein kinase C inactivates the transcription of the chick myogenin gene [Huang, C.-F., Neville, C. M. & Schmidt, J. (1993) Control of myogenic factor genes by the membrane depolarization/protein kinase C cascade in chick skeletal muscle, FEBS Lett. 319, 21-25] [17].

Regulatory relationships of MYOG

• In contrast, adult myoblasts are essentially negative for MyoD and myogenin by culture Day 1 and subsequently express first MyoD and then myogenin before expressing sarcomeric myosin [18].

Other interactions of MYOG

• Differential trans-activation of muscle-specific regulatory elements including the mysosin light chain box by chicken MyoD, myogenin, and MRF4 [19].
• In this study, we have isolated and characterized the chicken Myf5 gene, and cDNA clones encoding chicken MyoD1 and myogenin [20].
• These results indicate that the expression of myogenin mRNA and total RNA remains elevated during either slow or maintenance periods of stretch-induced increases in ALD mass, when SRF mRNA has returned to control levels [1].

Analytical, diagnostic and therapeutic context of MYOG

• Using the technique of electrophoretic mobility shift assay combined with order-of-addition and time-course experiments, we find that heterodimerization of myogenin with E12 occurs prior to DNA-binding [8].
• The state of phosphorylation of myogenin was followed by 32P-labeling and immunoprecipitation with an anti-myogenin antibody [13].
• These results attest to a special role for myogenin in the activation of AChR genes in denervation supersensitivity [16].
• Myogenic factor genes were found to respond differentially to electrical stimulation of denervated chick skeletal muscle [16].
• Moreover, both myogenin and CMD1 mRNA levels increase after muscle denervation in chicks [14].

References