CHARACTERIZATION OF T48, A TARGET OF HOMEOTIC GENE-REGULATION IN DROSOPHILA EMBRYOGENESIS

In Drosophila, the homeotic genes encode transcription factors which s pecify segmental identities during embryogenesis by directly regulatin g subordinate target genes. A chromatin immunopurification approach ha s been used to identify targets of the homeotic gene Ultrabithorax (Ub x). We report here the characterisation of a candidate target gene whi ch is positively regulated by the homeotic genes Ubx and abdominal-A i n both the epidermis and the midgut visceral mesoderm and encodes a no vel transmembrane protein. By mapping the cis-regulatory legions of th is gene, we have identified elements responsible for mediating homeoti c regulation, and show that they contain in vitro Ubx binding sites. T herefore, we suggest that this is an example of a direct target of reg ulation by homeotic genes in two germlayers.