Mouly V, Edom F, Decary S, Vicart P, Barbert J P, Butler-Browne G S
URA CNRS 1448, UFR Biomédicale des St. Pères, Paris, France.
Exp Cell Res. 1996 Jun 15;225(2):268-76. doi: 10.1006/excr.1996.0176.
The growth of muscle fibers during late development as well as in regeneration following muscle injury is the result of the proliferation and differentiation of satellite cells. However, all human cells, including satellite cells, show a limit in their proliferation. In order to define a cellular system with enhanced proliferative capacity, human satellite cells were transfected with a construct containing large T antigen from SV40 under the control of the human vimentin promoter. Vimentin is normally expressed during proliferation, and its expression is down-regulated as differentiation proceeds. In transfected cells, the construct is regulated like the endogenous vimentin gene. The effect of exogenous T antigen expression on both the proliferation and differentiation of human satellite cells was investigated. T antigen expression reduced the doubling time of human satellite cells from 36 to 20 h and increased the final proliferative capacity from 46 to 69 mean population doublings. When differentiation was triggered, although T antigen did not prevent the formation of myotubes, fusion was delayed. A similar delay was observed in the appearance of myogenin protein, one of the HLH regulatory factors, but not in the corresponding mRNA. Finally, T antigen has an effect on adult myosin isoform expression, since both adult slow and fast isoforms were only detected in myotubes negative for T antigen. These results led us to propose a model of the possible interactions between T antigen and muscle-specific factors.
在发育后期以及肌肉损伤后的再生过程中，肌纤维的生长是卫星细胞增殖和分化的结果。然而，包括卫星细胞在内的所有人类细胞，其增殖都存在极限。为了定义一种具有增强增殖能力的细胞系统，用人波形蛋白启动子控制下含有来自SV40的大T抗原的构建体转染人卫星细胞。波形蛋白在增殖过程中正常表达，随着分化的进行其表达下调。在转染细胞中，该构建体的调控方式与内源性波形蛋白基因相同。研究了外源性T抗原表达对人卫星细胞增殖和分化的影响。T抗原表达将人卫星细胞的倍增时间从36小时缩短至20小时，并将最终增殖能力从46次平均群体倍增提高到69次。当触发分化时，虽然T抗原并未阻止肌管的形成，但融合过程延迟。在一种HLH调节因子肌细胞生成素蛋白的出现上也观察到类似的延迟，但在相应的mRNA中未观察到。最后，T抗原对成人肌球蛋白同工型表达有影响，因为仅在T抗原阴性的肌管中检测到成人慢速和快速同工型。这些结果使我们提出了一个T抗原与肌肉特异性因子之间可能相互作用的模型。
