Cloning and expression of noz1, a zebrafish zinc finger gene related to Drosophila nocA.

We report the isolation of noz1, a novel zebrafish zinc finger gene which displays sequence similarity to Drosophila nocA. noz1 transcripts are detected at the shield stage within the germ ring and excluded from the most dorsal region. By the end of gastrulation, noz1 is expressed in the presumptive hindbrain and spinal cord as well as in the forming tailbud. During somitogenesis noz1 shows a dynamic expression in the midbrain-hindbrain boundary, hindbrain and spinal cord. This results, at 24 hpf, in a graded expression with the highest level in rhombomeres 2 and 3, and the lowest in the spinal cord. Expression analysis in swirl and chordino mutants as well as in retinoic acid treated embryos indicate that noz1 is activated by BMP antagonists and neural posteriorizing signals.