Identification of the novel developmentally regulated gene, Bdm2, which ishighly expressed in fetal rat brain

Most of the neurogenesis take place during the embryonic stage; the genes e xpressed predominantly in this stage may play important roles in the contro l of development of the central nervous system. Using a differential displa y method, we identified the novel rat gene, brain development-related molec ule 2 (Bdm2), that is expressed more abundantly in the embryonic brain than in the adult brain. Full-length Bdm2 cDNA consists of 1842 base pairs (bp) and contains an open reading frame of 1260 bp. Northern blot analysis demo nstrated that Bdm2 was strongly expressed in the late embryonic brain and w as still detected at lower levels in an early postnatal period; in adults, Bdm2 mRNA was decreased to an undetectable level in brain, though the expre ssion of this mRNA was revealed in other tissues. Level of Bdm2 mRNA was ma intained during neuronal differentiation of mouse embryonal carcinoma cell P19, but decreased during the differentiation to glial and unidentified non -neuronal cells. In situ hybridization study demonstrated the wide distribu tion of Bdm2 mRNA in the embryonic brain; in the adult brain, the hybridiza tion signals became more restricted to the hippocampus, olfactory bulb, cer ebellum, and neocortex, almost coinciding with the regions where nascent an d immature neurons are present. Thus, it appears likely that Bdm2 encodes a protein that is involved in both the regulation of growth of undifferentia ted neural cells and the terminal differentiation of neuronal cells. (C) 20 00 Elsevier Science B.V. All rights reserved.