A ZEBRAFISH SIX4 HOMOLOG WITH EARLY EXPRESSION IN HEAD MESODERM

Similar to the Drosophila homeobox gene sine oculis, several of the ve rtebrate homologues (Six genes) are expressed during eye formation and differentiation. In addition, most of these vertebrate genes show exp ression in mesodermal derivatives in adults and/or earlier stages of d evelopment. We have identified a zebrafish (Danio rerio) gene, six8, w hich shows the greatest similarity to murine Six4. The deduced protein s of these two genes have an overall sequence identity of 41%, while t he homeodomains and Six domains are highly conserved, 90% and 81%, res pectively. The spatiotemporal expression pattern of six8 was analyzed by RT-PCR and in situ hybridization. Transcripts were detected in a wi de range of embryonic stages and in adults. Notably, the strongest exp ression was observed in head mesoderm of late gastrula and early neuru la stages. (C) 1998 Elsevier Science B.V. All rights reserved.