Shi Y, Zhai H, Wang X, Wu H, Ning X, Han Y, Zhang D, Xiao B, Wu K, Fan D
Institute of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Shaanxi Province, PR China.
Cell Mol Life Sci. 2002 Sep;59(9):1577-83. doi: 10.1007/s00018-002-8531-6.
We report the isolation and functional characterization of the gene encoding MGr1-Ag, a multidrug-resistance-associated protein. A lambdagt11 cDNA library derived from colorectal carcinoma SW480 cells was screened with monoclonal antibody MGr1. DNA homology analysis of 22 positive clones (designated R1-R22) suggested human 37-kDa laminin receptor precursor (37LRP, R7/R9/R15/R16/R19/R20) and a novel gene (R22) as candidate genes encoding MGr1-Ag. Western blot analysis showed that anti-R20 serum reacted with a unique protein band that was consistent with MGr1-Ag, while anti-R22 serum could not react with MGr1-Ag. The coding gene for MGr1-Ag was amplified using reverse transcription-PCR. Sequence analysis revealed that the MGr1-Ag and 37LRP genes shared the same coding sequence. An in vitro drug sensitivity assay indicated that down-regulation of 37LRP by an antisense technique could significantly enhance the cytotoxicity of anticancer drugs to gastric cancer cells. Thus we draw the conclusion that MGr1-Ag is identical to 37LRP.
我们报告了编码MGr1-Ag（一种多药耐药相关蛋白）的基因的分离及功能特性。用单克隆抗体MGr1筛选源自结肠直肠癌SW480细胞的λgt11 cDNA文库。对22个阳性克隆（命名为R1-R22）的DNA同源性分析表明，人37-kDa层粘连蛋白受体前体（37LRP，R7/R9/R15/R16/R19/R20）和一个新基因（R22）是编码MGr1-Ag的候选基因。蛋白质免疫印迹分析显示，抗R20血清与一条与MGr1-Ag一致的独特蛋白带发生反应，而抗R22血清不能与MGr1-Ag发生反应。使用逆转录PCR扩增MGr1-Ag的编码基因。序列分析表明，MGr1-Ag和37LRP基因具有相同的编码序列。体外药敏试验表明，通过反义技术下调37LRP可显著增强抗癌药物对胃癌细胞的细胞毒性。因此我们得出结论，MGr1-Ag与37LRP相同。
