CLONING AND CHARACTERIZATION OF THE DROSOPHILA HOMOLOG OF THE AP-2 TRANSCRIPTION FACTOR

The AP-2 family of transcription factors (AP-2 alpha, AP-2 beta and AP -2 gamma) is temporally and spatially regulated in mammals and has als o been implicated in oncogenesis. Here we report the isolation of geno mic and cDNA clones encoding the Drosophila homologue of AP-2, designa ted DAP-2. The predicted amino acid sequence exhibits 42-45% overall i dentity with the vertebrate AP-2 proteins, A sequence of 107 amino aci ds within the DNA binding and dimerization domain of the vertebrate AP -2 proteins is highly conserved (90-92%) with the DAP-2 homologue. An in vitro translation product of DAP-2 cDNA binds specifically to AP-2 consensus binding sites. DAP-2 was also shown to be functionally conse rved ill vivo because transient transfection of a DAP-2 expression pla smid activated transcription through AP-2 binding sites in both mammal ian and Drosophila cell lines. DAP-2 is expressed during early embryog enesis and DAP-2 transcripts are also detected in the adult. Whole-mou nt in situ hybridizations demonstrated that DAP-2 is expressed initial ly at stage 9 of Drosophila embryonic development and that DAP-2 trans cripts are detected in regions of the brain, eye-antennal disc, optica l lobe, antenno-maxillary complex, and in a subset of cells of the ven tral nerve cord. The cloning of DAP-2 and the identification of the DA P-2 expression pattern during embryogenesis provides a starting point to address the function of AP-2 during differentiation and development in a well understood model system.