Dev. Biol.

Nodal signaling is critical for a variety of processes during vertebrate development, including gastrulation and left—right patterning. Although many of the molecules that play a role in the transduction of Nodal signals are known, the current list of genes known to be regulated by Nodal signals is incomplete. We identified putative Nodal regulated genes by differential RNA hybridization against a zebrafish cDNA library of about 14,000 cDNAs. Putative Nodal-regulated genes were also identified by screening zebrafish gene expression databases for genes expressed in the margin or shield of early gastrula-stage embryos. Putative Nodal-regulated genes were then screened by in situ hybridization against wild-type and maternal-zygotic one eyed pinhead embryos, which lack all Nodal signaling. This led to the identification of 57 unique Nodal-regulated genes. We are currently analyzing the function and regulation of these genes