Drummond J T, Li G M, Longley M J, Modrich P
Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA.
Science. 1995 Jun 30;268(5219):1909-12. doi: 10.1126/science.7604264.
A mismatch-binding heterodimer of hMSH2 and a 160-kilodalton polypeptide has been isolated from HeLa cells by virtue of its ability to restore mismatch repair to nuclear extracts of hMSH2-deficient LoVo colorectal tumor cells. This heterodimer, designated hMutS alpha, also restores mismatch repair to extracts of alkylation-tolerant MT1 lymphoblastoid cells and HCT-15 colorectal tumor cells, which are selectively defective in the repair of base-base and single-nucleotide insertion-deletion mismatches. Because HOT-15 cells appear to be free of hMSH2 mutations, this selective repair defect is likely a result of a deficiency of the hMutS alpha 160-kilodalton subunit, and mutations in the corresponding gene may confer hypermutability and cancer predisposition.
通过其恢复hMSH2缺陷型LoVo结肠直肠肿瘤细胞核提取物错配修复的能力，已从HeLa细胞中分离出hMSH2与一种160千道尔顿多肽的错配结合异二聚体。这种异二聚体，命名为hMutSα，也能恢复耐烷基化MT1淋巴母细胞和HCT - 15结肠直肠肿瘤细胞核提取物的错配修复，这些细胞在碱基 - 碱基和单核苷酸插入 - 缺失错配修复中存在选择性缺陷。由于HCT - 15细胞似乎没有hMSH2突变，这种选择性修复缺陷可能是hMutSα 160千道尔顿亚基缺陷的结果，相应基因的突变可能导致高突变性和癌症易感性。
