Oxidative Stress Induced Growth Inhibitor 1 (OSGIN1)

The deduced 317-amino acid protein has a calculated molecular mass of about 34.5 kD. OKL38 does not have a transmembrane domain or signal peptide. Minor transcripts of 3.6 and 4.0 kb were also observed.

In situ hybridization detected Okl38 in undifferentiated mammary epithelial cells of nonpregnant rats, and expression was upregulated in secretory epithelial of 18-day pregnant rats. Northern blot analysis detected reduced OKL38 expression in human breast cancer cell lines compared with normal mammary tissue. Expression was also reduced in chemically-induced rat mammary tumors. Overexpression of OKL38 in a human breast cancer cell line reduced the ability of these cells to form tumors in nude mice.