IDENTIFICATION OF MAMMAGLOBIN-B, A NOVEL MEMBER OF THE UTEROGLOBIN GENE FAMILY

In this report, we have identified, sequenced, and characterized the e xpression pattern of a novel human gene, mammaglobin B. Mammaglobin B (MGB2) is highly homologous to mammaglobin (MGB1), a previously charac terized human gene whose expression is limited to the mammary epitheli um and frequently up-regulated in human breast cancer cells. Based upo n amino acid sequence similarities, both mammaglobin and mammaglobin B may be considered members of a larger, mammalian multigene family tha t includes rabbit uteroglobin, human Clara Cell 10-kDa protein (CC10), and the multimeric rat prostatein protein. Together with the human CC 10 gene, mammaglobin and mammaglobin B are closely linked on human chr omosome 11q13. However, despite their primary sequence similarity and close chromosomal proximity, the expression of mammaglobin and mammagl obin B is nonconcordant in both nonmalignant and neoplastic tissue, (C ) 1998 Academic Press.