Activation of ATBF1, a multiple-homeodomain zinc-finger gene, during neuronal differentiation of murine embryonal carcinoma cells.

ATBF1 is a transcription factor containing four homeodomains and 17 zinc fingers. Since the Drosophila homolog, ZFH-2, is implicated in neurogenesis, we examined ATBF1 expression in developing mouse brain and in P19 mouse embryonal carcinoma cells during differentiation. We found that pre- and postnatal mouse brains expressed high levels of ATBF1 mRNA, but the adult brain contained only a small amount of ATBF1 transcripts. In P19 cells, ATBF1 transcripts were undetectable before differentiation; however, 1 day after induction of neuronal differentiation with retinoic acid, ATBF1 mRNA was expressed at a high level. This increased level reached a maximum on the 4th day and then declined. No comparable level of ATBF1 mRNA was expressed when P19 cells were treated with dimethyl sulfoxide to induce muscle cells. These temporal patterns of ATBF1 expression in vivo and in vitro suggest that ATBF1 may play a role in neuronal differentiation.