Hermo H, Duigou G J, Babiss L E, Fisher P B
Carcinogenesis. 1987 Jul;8(7):967-75. doi: 10.1093/carcin/8.7.967.
Pretreatment of cloned rat embryo fibroblast (CREF) cells with methyl methanesulfonate (MMS) prior to infection with wild-type 5 adenovirus (H5wt) or a temperature-sensitive mutant of Ad5 (H5ts125) results in an MMS dose-dependent enhancement of viral transformation. With both viral isolates, MMS enhanced the transformation frequency when normalized for cell toxicity but did not induce a carcinogen dose-dependent increase in the absolute number of foci above solvent-treated controls. In contrast, pretreatment of CREF cells with MMS prior to infection with a host-range mutant of Ad5 (H5hr1) which contains a single basepair deletion in the E1a-transforming region of Ad5 and displays a cold-sensitive transformation phenotype, results in an MMS dose-dependent increase in the absolute number of transformed foci in comparison with solvent-treated controls as well as an increase in transformation frequency when normalized for cell toxicity. To explore the possible mechanism by which H5hr1 displays its unique carcinogen-enhancement of transformation (CET) phenotype we have examined the effect of MMS pretreatment on the frequency of transformation of CREF cells infected with mutants of Ad5 which were engineered to contain either a deletion (H5dl101) or an insertion (H5in106) mutation in the E1a gene region resulting in a cold-sensitive transformation phenotype similar to H5hr1. MMS-pretreated CREF cells infected with H5dl101 or H5in106 did not demonstrate a dose-dependent increase in the absolute number of transformed foci as was observed with carcinogen-pretreated H5hr1-infected CREF cells. These findings suggest that the unique CET phenotype displayed by H5hr1 may result from a second site mutation in a region of H5hr1 other than the E1a-transforming region and/or a novel interaction between gene products resulting from the specific mutation in E1a and other region(s) of the H5hr1 genome. Our investigations also indicate that the CREF/H5hr1 system should prove useful in analyzing chemical-viral interactions in cell transformation.
在用野生型5型腺病毒（H5wt）或Ad5的温度敏感突变体（H5ts125）感染之前，用甲磺酸甲酯（MMS）对克隆的大鼠胚胎成纤维细胞（CREF）进行预处理，会导致病毒转化在MMS剂量依赖性增强。对于这两种病毒分离株，当针对细胞毒性进行归一化时，MMS提高了转化频率，但并未诱导出高于溶剂处理对照组的致癌剂剂量依赖性灶绝对数量增加。相比之下，在用Ad5的宿主范围突变体（H5hr1）感染之前，用MMS对CREF细胞进行预处理，该突变体在Ad5的E1a转化区域含有一个单碱基对缺失，并表现出冷敏感转化表型，与溶剂处理对照组相比，MMS剂量依赖性地增加了转化灶的绝对数量，并且在针对细胞毒性进行归一化时也增加了转化频率。为了探究H5hr1展现其独特的致癌剂增强转化（CET）表型的可能机制，我们研究了MMS预处理对感染Ad5突变体的CREF细胞转化频率的影响，这些突变体被设计为在E1a基因区域含有缺失（H5dl101）或插入（H5in106）突变，从而导致类似于H5hr1的冷敏感转化表型。用H5dl101或H5in106感染的MMS预处理CREF细胞，并未像用致癌剂预处理的H5hr1感染的CREF细胞那样表现出转化灶绝对数量的剂量依赖性增加。这些发现表明，H5hr1展现的独特CET表型可能是由于H5hr1中除E1a转化区域之外的区域发生了第二位点突变和/或E1a中特定突变产生的基因产物与H5hr1基因组其他区域之间的新型相互作用所致。我们的研究还表明，CREF/H5hr1系统在分析细胞转化中的化学 - 病毒相互作用方面应会被证明是有用的。
