Characterization and expression pattern of two zebrafish atf7 genes.

Members of the ATF/CREB (activating transcription factor/cAMP-responsive element binding protein) transcription factor family play diverse roles in controlling cell proliferation, apoptosis, and oncogenesis, as well as in embryonic development of vertebrates. We identified two zebrafish orthologs of human ATF7 gene: atf7a and atf7b. Whole-mount in situ hybridization shows that zebrafish atf7a is first expressed in the notochord precursors at 80% epiboly stage and then in the developing notochord during segmentation. The expression of atf7a is positively regulated by ntl, flh, and spr2, which are involved in development of the notochord. In contrast, atf7b is maternally expressed and during embryogenesis its mRNA is ubiquitously distributed, showing an expression pattern similar to that of mammalian Atf7.