Loh T P, Sievert L L, Scott R W
E. I. du Pont de Nemours and Company, Inc., Central Research and Development Department, Wilmington, Delaware 19898.
J Virol. 1988 Nov;62(11):4086-95. doi: 10.1128/JVI.62.11.4086-4095.1988.
An intragenic region spanning the tRNA primer binding site of a Moloney murine leukemia virus recombinant retrovirus was found to restrict expression specifically in embryonal carcinoma (EC) cells. When the inhibitory domain was present, the levels of steady-state RNA synthesized from integrated recombinant templates in stable cotransformation assays were reduced 20-fold in EC cells but not in C2 myoblast cells. Transient-cotransfection assays showed that repression of a template containing the EC-specific inhibitory component was relieved by an excess of specific competitor DNA. In addition, repression mediated by the inhibitory component was orientation independent. This evidence demonstrates the presence of a saturable, trans-acting negative regulatory factor(s) in EC cells and suggests that the interaction of the factor(s) with the intragenic inhibitory component occurs at the DNA level.
发现一个跨越莫洛尼鼠白血病病毒重组逆转录病毒tRNA引物结合位点的基因内区域，它特异性地限制了胚胎癌细胞（EC细胞）中的表达。当存在抑制结构域时，在稳定共转化试验中，从整合的重组模板合成的稳态RNA水平在EC细胞中降低了20倍，而在C2成肌细胞中则没有。瞬时共转染试验表明，过量的特异性竞争DNA可解除对含有EC特异性抑制成分的模板的抑制。此外，抑制成分介导的抑制作用与方向无关。这一证据证明了EC细胞中存在一种可饱和的反式作用负调节因子，并表明该因子与基因内抑制成分的相互作用发生在DNA水平。
