Genes expressed during imaginal discs morphogenesis: IMP-L2, a gene expressed during imaginal disc and imaginal histoblast morphogenesis.

We describe our analysis of IMP-L2, one of a set of six ecdysone-inducible genes in imaginal discs of Drosophila whose transcripts are associated with membrane-bound polysomes. The spatial and temporal patterns of expression of the IMP-L2 transcript were analyzed. This transcript is first expressed in imaginal discs in areas that are precursors of head and thoracic epithelium, particularly the peripodial epithelia. It is later expressed in the imaginal histoblasts, precursors of the adult abdomen. The appearance of IMP-L2 transcript in each of these tissues precedes the spreading and fusion of the separate imaginal anlagen to form the continuous adult epidermis.