SEQUENCE-ANALYSIS OF THE ZEBRAFISH HOX-B5 B6 REGION/

The region between the zebrafish homeobox genes hox-B5 and hox-B6 was sequenced, and searched for consensus binding sites of retinoic acid r eceptors and other transcription factors. A continuous sequence of 7.2 kb covering the zebrafish hox-B5/B6 genes was then compared to the co rresponding region of the mouse Hox-B complex. Except for the open rea ding frames, the only highly conserved regions that could be found wer e stretches extending 0.3 kb upstream from the initiation codons. With in the conserved upstream regions of hox-B5/B6, we identified a common 10 bp sequence, which is also present close to the initiation codons of several other Hox genes and which therefore may be implicated in th e control of their expression.