Van De Klundert F A, Bloemendal H
Department of Biochemistry, Faculty of Science, University of Nijmegen, The Netherlands.
Mol Biol Rep. 1994;20(3):143-8. doi: 10.1007/BF00990546.
Transformation of hamster primary myoblasts with the SV40 large T antigen leads to inhibition of terminal differentiation. This process is associated with a block in the transcription of the muscle-specific determinator genes MyoD and myogenin. The effect of SV40 large T antigen on the terminal differentiation is dominant and cannot be bypassed by re-expression of retrovirally encoded MyoD. The intermediate filament protein desmin is normally up-regulated when myoblasts differentiate into myotubes. Surprisingly, desmin is expressed at relatively high levels in transformed hamster muscle cells grown under proliferative conditions. So desmin expression can be independent of the onset of differentiation. This is in accordance with the expression of the protein in fibroblasts, infected with a MyoD-encoding retrovirus and grown under proliferative conditions, when no other muscle-specific proteins are present.
用SV40大T抗原转化仓鼠原代成肌细胞会导致终末分化受到抑制。这一过程与肌肉特异性决定基因MyoD和肌细胞生成素的转录受阻有关。SV40大T抗原对终末分化的影响是显性的，逆转录病毒编码的MyoD重新表达无法绕过这种影响。当成肌细胞分化为肌管时，中间丝蛋白结蛋白通常会上调。令人惊讶的是，在增殖条件下生长的转化仓鼠肌肉细胞中，结蛋白以相对较高的水平表达。因此，结蛋白的表达可以独立于分化的开始。这与在增殖条件下生长且不存在其他肌肉特异性蛋白时，感染了编码MyoD的逆转录病毒的成纤维细胞中该蛋白的表达情况一致。
