DROSOPHILA HOX COMPLEX DOWNSTREAM TARGETS AND THE FUNCTION OF HOMEOTIC GENES

Hox complex genes are key developmental regulators highly conserved th roughout evolution. The encoded proteins share a 60-amino-acid DNA-bin ding motif, the homeodomain, and function as transcription factors to control axial patterning. An important question concerns the nature an d function of genes acting downstream of Hox proteins. This review foc uses on Drosophila, as little is known about this question in other or ganisms. The noticeable progress gained in the field during the past f ew years has significantly improved our current understanding of how H ox genes control diversified morphogenesis. Here we summarise the stra tegies deployed to identify Hox target genes and discuss how their fun ction contributes to pattern formation and morphogenesis. The regulati on of target genes is also considered with special emphasis on the mec hanisms underlying the specificity of action of Hox proteins in the wh ole animal.