Expression profiles and intergenic structure of head-to-head oriented Brca1 and Nbr1 genes

Mouse and human Brca1/BRCA1 and Nbr1/NBR2 genes lie head-to-head, being tra nscribed from the opposite strands. The normal function of Brca1 is associa ted with DNA damage-related responses and the maintenance of genome integri ty. Mutations of this gene are major risk factors for developing breast and ovarian cancers. The function of Nbr1 is unknown. Here we analyzed express ion profiles of Brca1 and a newly identified, evolutionary conserved isofor m of Nbr1(1a) transcript. In adult testis, the Nbr1(1a) mRNA showed an 18-f old higher steady-state level than the: ubiquitous Nbr1(1b) form and its ex pression was confined mainly to spermatids. The expression profile of Brca1 paralleled that of Nbr1(1b). The Nbr1(1a) mRNA was not significantly expre ssed in normal somatic tissues, but was found on a list of cDNA clones from a human myeloblast cell line. The newly defined intergenic region (289 bp) between Nbr1 and Brca1 in the mouse and rat corresponds well to that of hu man BRCA1-NBR2 region. (C) 2001 Elsevier Science B.V. All rights reserved.