Laufer R, Klarsfeld A, Changeux J P
UA CNRS D1284 Neurobiologie Moléculaire, Département des Biotechnologies, Institut Pasteur, France.
Eur J Biochem. 1991 Dec 18;202(3):813-8. doi: 10.1111/j.1432-1033.1991.tb16437.x.
Protein kinase C has previously been implicated in the regulation of chicken acetylcholine receptor (AChR) gene expression. To investigate the molecular basis of this regulation, the promoter of the AChR alpha-subunit (alpha AChR) gene was linked to a reporter gene and introduced into cultured chick myotubes by transient transfection. Treatment of myotubes with protein-kinase-C-activating phorbol esters was found to inhibit promoter activity. These inhibitory actions were mediated by promoter sequences between nucleotides -110 and -45, relative to the start point of transcription of the alpha AChR gene. In particular, phorbol-ester responsiveness could be conferred by a short DNA sequence that contains one of the two MyoD binding sites of the alpha AChR gene muscle-specific enhancer. 12-O-Tetradecanoylphorbol 13-acetate was found to inhibit rapidly and potently the expression of mRNAs coding for the myogenic regulators CMD1 and myogenin. Moreover, its inhibitory effect on the alpha AChR gene promoter could be attenuated by cotransfection of a MyoD1 expression vector. These results provide a molecular basis for the previously demonstrated involvement of protein kinase C in the regulation of alpha AChR biosynthesis. In addition, they lend further support to the notion that myogenic proteins play an important role in the control of alpha AChR gene expression.
蛋白激酶C此前被认为参与鸡乙酰胆碱受体（AChR）基因表达的调控。为了研究这种调控的分子基础，将AChRα亚基（αAChR）基因的启动子与一个报告基因相连，并通过瞬时转染导入培养的鸡肌管。发现用激活蛋白激酶C的佛波酯处理肌管可抑制启动子活性。这些抑制作用是由相对于αAChR基因转录起始点的核苷酸-110至-45之间的启动子序列介导的。特别是，佛波酯反应性可由一个短DNA序列赋予，该序列包含αAChR基因肌肉特异性增强子的两个MyoD结合位点之一。发现12-O-十四酰佛波醇13-乙酸酯能快速且有效地抑制编码生肌调节因子CMD1和肌细胞生成素的mRNA的表达。此外，通过共转染MyoD1表达载体可减弱其对αAChR基因启动子的抑制作用。这些结果为先前证明的蛋白激酶C参与αAChR生物合成的调控提供了分子基础。此外，它们进一步支持了生肌蛋白在αAChR基因表达控制中起重要作用的观点。
