DISSECTION OF THE DROSOPHILA PAIRED PROTEIN - FUNCTIONAL REQUIREMENTSFOR CONSERVED MOTIFS

The Drosophila paired gene encodes three conserved motifs: a homeodoma in, paired domain and PRD (his/pro) repeat. To investigate the functio nal importance of the PRD repeat and paired domain, we tested deletion mutants using an ectopic expression assay in embryos. Our results sug gest that the PRD repeat is not required for the in vivo regulation of the target genes, engrailed and gooseberry. However, the PRD repeat a ppears to be embedded within a proline-rich transcriptional activation domain required for the regulation of these genes. Our analysis of th e paired domain indicated that its N-terminal half, which is required for DNA binding in vitro, is also required for in vivo function, where as surprisingly, the C-terminal half is dispensable for the regulation of engrailed and gooseberry.