During Drosophila hindgut development, bowl, caudal/CDX, brachyenteron/Brachyury/TBX, fork head/FOX, drumstick, lines, and wingless/WNT play important roles. Drosophila bowl gene is homologous to Drosophila odd-skipped (odd) gene and odd-skipped related gene (sob). Here, human OSR1, related to Drosophila odd, was isolated using bioinformatics and cDNA-PCR. OSR1 was found to encode 266 amino-acid protein with three C2H2-type zinc fingers, a tyrosine phosphorylation site (Tyr 203), and several putative PXXP SH3 binding motifs. Three zinc fingers and a tyrosine phosphorylation site were conserved among human OSR1, OSR2, Drosophila odd, sob, and bowl. OSR1 showed 63.6% total amino-acid identity with OSR2. OSR1 gene consisting of three exons was located on human chromosome 2p24. OSR1 mRNA of 2.3-kb in size was detected in adult colon, small intestine, prostate, testis, and fetal lung. OSR1 mRNA was significantly up-regulated in a pancreatic cancer cell line MIA PaCa-2, and was weakly expressed in gastric cancer cell lines OKAJIMA, MKN45, pancreatic cancer cell lines PANC-1, BxPC-3, AsPC-1, PSN-1, Hs766T, and esophageal cancer cell line TE10. Among 10 cases of primary gastric cancer, OSR1 mRNA was up-regulated in 5 cases, and was down-regulated in 2 cases. This is the first report on molecular cloning and characterization of human OSR1.

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