Molecular cloning of a novel human gene on chromosome 4p11 by immunoscreening of an ovarian carcinoma cDNA library

In our efforts to identify immunoreactive antigens in ovarian cancer, we us ed the method of immunoscreening of an ovarian carcinoma cDNA expression li brary with ascites fluid from ovarian cancer patients, Among many positive clones, one was found to contain partial sequence of a novel gene. By searc hing expressed sequence tags (ESTs) and human genome project databases as w ell as by screening other cDNA libraries and by RT-PCR strategies, we were able to obtain the full-length cDNA sequence (1.4 kb) and establish the gen omic organization of this new gene. We also identified two alternatively sp liced forms, encoding for slightly different proteins, The longer form (1.4 kb) is predicted to encode for a 27.6 kDa protein of 245 amino acids. The shorter form (1.3 kb) encodes for a truncated protein of 20.7 kDa and 208 a mino acids, These proteins are not significantly homologous to any known pr otein in the GenBank database. This gene is composed of nine exons and eigh t introns, By fluorescence in situ hybridization (FISH), it was mapped to c hromosome 4p11. This gene is highly expressed in many tissues, including te stis, brain, placenta, ovary, prostate, and mammary gland, The high level e xpression of the shorter form is restricted to the central nervous system, including brain, cerebellum and spinal cord, suggesting that this form may have a unique function in the central nervous system, (C) 2001 Academic Pre ss.