Rayevskaya G B, Varshaver N B, Shapiro N I
Molecular Genetics U.S.S.R. Academy of Sciences, Moscow.
Cancer Genet Cytogenet. 1989 Jan;37(1):39-47. doi: 10.1016/0165-4608(89)90072-1.
By using a selection procedure that excluded the transforming effect of SV40, reversions to several properties of normal phenotype were for the first time obtained in a transformed Chinese hamster cell line after SV40 infection. The value of induction to recovery of contact inhibition was typical for SV40-induced reverse gene mutations. Thirteen of 15 isolated revertant clones were T-antigen positive, thus synthesizing the product of viral oncogene. Therefore, in the majority of clones reversion occurred in spite of the presence of viral transforming protein. Dot hybridization revealed the presence of SV40 DNA in all revertants including those expressing no T antigen. The virus rescued from one T-antigen positive and two negative clones proved to be infectious. Reversion to contact inhibition was followed by reversion as regards serum requirements and growth in soft agar. However, in all cases reversion was partial. Karyologic analysis of revertant clones showed that six clones maintained the hypodiploid karyotype of the parental clone, six revertants were near-tetraploid, and one was near triploid. The possible events underlying the SV40-induced reversions to normal phenotype and the role of virus-induced mutations in viral carcinogenesis are discussed.
通过使用一种排除SV40转化作用的筛选程序，在SV40感染后的一个转化中国仓鼠细胞系中首次获得了向正常表型的几种特性的回复突变。诱导恢复接触抑制的现象是SV40诱导的反向基因突变的典型表现。15个分离的回复克隆中有13个T抗原呈阳性，因此合成了病毒癌基因的产物。所以，尽管存在病毒转化蛋白，大多数克隆仍发生了回复突变。斑点杂交显示所有回复突变体中都存在SV40 DNA，包括那些不表达T抗原的回复突变体。从一个T抗原阳性克隆和两个阴性克隆中拯救出的病毒被证明具有感染性。回复到接触抑制之后，在血清需求和软琼脂生长方面也出现了回复突变。然而，在所有情况下，回复都是不完全的。对回复克隆的染色体分析表明，6个克隆保持了亲本克隆的亚二倍体核型，6个回复突变体接近四倍体，1个接近三倍体。文中讨论了SV40诱导回复到正常表型的潜在可能事件以及病毒诱导的突变在病毒致癌作用中的作用。
