A zebrafish homeobox-containing gene with embryonic transcription.

A genomic library of zebrafish (Brachydanio rerio) was constructed and screened with homeobox-containing probes. One of the strongly cross-hybridizing clones was characterized by DNA sequencing. The deduced amino acid sequence exhibits extensive homology (greater than 80%) relative to the Antennapedia-class of Drosophila homeobox sequences. Characterization of the gene with respect to expression demonstrated that two transcripts of 2.1 and 1.4 kb, respectively, are present in embryonic poly (A+) RNA. The highest concentration of the two RNA species was observed in embryos which have terminated the process of somite formation.