胃癌下调全长基因GDDR的克隆及与胃癌关系的研究

Down-regulated full-length novel gene GDDR and its effect on gastric cancer

目的 从成功建立的用于筛选胃癌下调新基因的抑制消减杂交cDNA文库中克隆全长新基因 ;检测其在胃癌及正常胃黏膜组织中的表达 ,分析其在胃癌发生发展中的作用。方法 随机挑选阳性克隆测序筛选基因片段 ,cDNA末端快速扩增得到其全长。在 2 5例胃癌与正常胃黏膜RNA进行半定量RT PCR。生物信息分析基因结构、染色体定位 ,并行其推导蛋白性质与功能的研究。结果 筛选到一 331bp的基因片段 ,经cDNA末端快速扩增 ,得到了长度 75 0bp的全长新基因。命名为GDDR ,被国际GenBank收录 ,收录号 :AF4 94 5 0 9。RT PCR表明它在胃癌中明显下调 (GDDR/ β 肌动蛋白 13 5± 5 1与 1 0 4± 0 2 0 ,P <0 0 1)。染色体定位 2 p13,由 5个外显子组成。与CA11在染色体上的距离仅差 2 2kbp ,即均位于 2 p13。其编码蛋白前有一跨膜肽区 ,与胃癌候选抑癌基因CA11编码蛋白为同源蛋白 ,均为新的BRICHO家族成员。结论 得到一胃癌下调全长新基因GDDR ,它可能为BRICHO家族中又一胃癌相关基因。

Objective To clone gene fragments from suppression substructive library established for screening down-regulated genes in gastric carcinoma, and obtain the full-length novel gene. Methods Gene fragments were identified by sequencing plasmids of positive colonies chosen randomly. One gene fragment was amplified by RACE, and the full-length novel gene was obtained. Expression of novel gene mRNA was respectively detected by semi-quantitative PCR in the gastric carcinoma tissues and counterpart normal gastric mucous membrane of 25 patients with gastric cancer. The structure of the full-length novel gene,location on chromosome, property of protein encoded by full-length novel gene and its function were investigated by Bio-message technique. Results One 331 bp gene fragment was cloned, and its full-length novel gene obtained by RACE. The novel full-length gene was named GDDR, registered in the number of AF494509 by GenBank. Significant down-regulated expression of GDDR gene mRNA in gastric carcinoma tissues was confirmed (GDDR/β-actin 13.474 ± 5.059 vs 1.041 ± 0.202, P <0.01). GDDR was located in chromosome 2p13 with 5 exons. As one member of new BRICHO family as CA11, GDDR encoding protein with transmembrane peptide revealed homology to protein encoded by CA11. Conclusion A novel full-length gene GDDR is obteined. GDDR likely is another gene of BRICHO family related to gastric cancer.