HeLa-MSH2-细胞的生物学特性

Biological characteristics of HeLa- MSH2^- cells

凝胶阻滞实验证实转染了本实验室构建的hMSH2反义RNA表达质粒的HeLa细胞（HeLa－MSH2-细胞），其细胞抽提物中C·T碱基对和A·C碱基对错配结合蛋白表达明显降低。该细胞系细胞与母本HeLa细胞在生长速率方面无差异，但经十几次传代后，其生长速率加快约两倍，出现了次磺酸磷酸核糖转移酶（hypoxanthinephosphoribosyltransferase,hgprt）自发突变率升高，但不存在N-甲基-N’-硝基-N-亚硝基胍（N－methyl－N’－nitro－N－nitrosogyanidine,MNNG）耐受。认为hMSH2蛋白在错配修复系统中起了错配识别和结合作用，但该基因的突变不能完全解释道传性非息向性结直肠癌（hereditarynonpolpoiscolorectalcarcinoma，HNPCC）病人来源的细胞系的生物学改变。

The expression of G T and A C mismatch binding protein was inhibited Obviously in HeLa MSH2 - cell, the hMSH2 antisense RNA expression plasmid transfected HeLa cell as demonstrated by gelretardation assay of its whole cell extant. The cell growth of this cell line was not different from HeLa cells soon after transfection, but after more than ten subcultures, it increased two feld. Spontaneous mutation rate of hypoxanthine phosphoribosyl transferase (hgprt) locus increased malkedly but no N - methyl-N' - nitro - N - nitrosoguanidine (MNNG) tolerance appeared in this cell line. These results suggested that hMSH2 protein played a role in mismatch recognition and binding in mismatch repair system, but the biological changes of hereditary nonpolyposis colorectal cancer (HNPCC) derived cell lines can' t be explained by hMSH2 gene mutation completely.