O'Neill F J, Cohen S, Renzetti L
J Virol. 1980 Jul;35(1):233-45. doi: 10.1128/JVI.35.1.233-245.1980.
Mouse embryo fibroblasts and 3T3 cells were transformed by wild-type, tsB4, tsA7, tsA58, and tsA209 simian virus 40. Clones of transformants were generated both in soft agar and in liquid medium by focus formation and at both high and relatively low multiplicities of infection. All transformants were assayed for three phenotypes of transformation: (i) the ability to form highly multinucleated cells in cytochalasin B-supplemented medium, i.e., uncontrolled nuclear division; (ii) the capacity to continue DNA synthesis at increasing cell density; and (iii) the ability to form colonies in soft agar. The great majority of mouse embryo fibroblast transformants generated with tsA mutant virus were temperature sensitive for transformation in all three assays, regardless of the input multiplicity or whether they were generated in liquid medium or soft agar. These transformants exhibited a normal or near-normal phenotype at the nonpermissive temperature of 40 degrees C. All but one of the transformants which appeared transformed at both temperatures were in the A209 group. In contrast to mouse embryo fibroblasts, transformants generated with 3T3 cells and tsA virus were often not temperature sensitive, exhibiting the transformation phenotypes at both temperatures. This phenomenon was more often observed when 3T3 transformants were generated in soft agar. These results, along with other published data, suggest that uncontrolled nuclear division and uncontrolled DNA synthesis are a function of the simian virus 40 A gene. Finally, with the 3T3 transformants, there was often discordance in the expression of transformation among the three phenotypes. Some tsA transformants were temperature sensitive in one of two assays but were transformed at both 33 and 40 degrees C in the remaining assay(s). Other transformants exhibited a normal cytochalasin B response at either temperature but were temperature sensitive in the other assays.
野生型、tsB4、tsA7、tsA58和tsA209猴病毒40转化了小鼠胚胎成纤维细胞和3T3细胞。通过焦点形成在软琼脂和液体培养基中，以及在高感染复数和相对低感染复数下产生转化体克隆。对所有转化体进行了三种转化表型的检测：(i) 在添加细胞松弛素B的培养基中形成高度多核细胞的能力，即不受控制的核分裂；(ii) 在细胞密度增加时继续进行DNA合成的能力；(iii) 在软琼脂中形成集落的能力。用tsA突变病毒产生的绝大多数小鼠胚胎成纤维细胞转化体在所有三种检测中对转化都是温度敏感的，无论输入的感染复数如何，也无论它们是在液体培养基还是软琼脂中产生的。这些转化体在40℃的非允许温度下表现出正常或接近正常的表型。在两个温度下都出现转化的所有转化体中，除了一个之外都属于A209组。与小鼠胚胎成纤维细胞相反，用3T3细胞和tsA病毒产生的转化体通常不是温度敏感的，在两个温度下都表现出转化表型。当在软琼脂中产生3T3转化体时，这种现象更常被观察到。这些结果与其他已发表的数据表明，不受控制的核分裂和不受控制的DNA合成是猴病毒40 A基因的功能。最后，对于3T3转化体，三种表型之间的转化表达常常不一致。一些tsA转化体在两种检测中的一种中是温度敏感的，但在其余的检测中在33℃和40℃时都发生了转化。其他转化体在任一温度下对细胞松弛素B的反应都是正常的，但在其他检测中是温度敏感的。
