RESUMO
<p><b>OBJECTIVE</b>To clone novel gene from suppression subtraction library established for screening down-regulated genes in gastric carcinoma, and the effects of novel gene on gastric tumorigenicity were analyzed.</p><p><b>METHODS</b>Sequencing results of 860 positive colonies chosen randomly were compared by Blast program in GenBank. Novel gene fragment was amplified by rapid amplification of cDNA ends (RACE). The mRNA expression of novel gene was detected by Northern blot and semi-quantitative PCR in 25 cases of gastric carcinoma tissue and counterpart normal gastric mucosa. The structure and chromosomal location of novel gene were investigated by Bio-message technique.</p><p><b>RESULTS</b>A 233 bp novel gene fragment was screened out from 860 clones and a 802 bp novel gene was obtained by RACE. The novel gene was named as GDDM, registered in the number of AF494508 by GenBank. The mRNA expression of GDDM in gastric carcinoma tissue (4.496+/-0.637) was significantly lower than that in the counterpart normal gastric mucosa (36.919+/-6.290)(P<0.01). Chromosomal location of GDDM gene was at 4q31.</p><p><b>CONCLUSION</b>The cloned novel gene, GDDM, is down-regulated in gastric carcinoma, and it is likely to be involved in gastric tumorigenicity.</p>