Morphogenesis in Aspergillus nidulans requires Dopey (DopA), a member of anovel family of leucine zipper-like proteins conserved from yeast to humans

DopA is the founding member of a novel protein family required for correct cell morphology and spatiotemporal organization of multicellular structures in the filamentous fungus Aspergillus nidulans. DopA homologues from Sacch aromyces cerevisiae (Dop1), Candida albicans, Caenorhabditis elegans, Rattu s norvegicus and Homo sapiens have been identified from genome sequencing p rojects. S. cerevisiae DOP1 is essential for viability and, like DopA, affe cts cellular morphogenesis. dopA encodes a large protein (207 kDa) containi ng several putative domains, including three leucine zipper-like domains. S trains with either the temperature-sensitive dopA1(ts) allele, which alters one of the leucine zippers, or the null Delta dopA allele, had abnormal mo rphology of the vegetative hyphae, delayed and asynchronous initiation of a sexual development, aberrant morphogenesis of the conidiophore and an early block in the sexual cycle. The expression patterns of key transcriptional regulators of the asexual and sexual cycle (brlA, abaA and steA) are altere d in a Delta dopA background, suggesting that DopA functions upstream in th e developmental pathway. Double mutant analysis showed that dopA interacts genetically with constitutively active and inactive forms of A. nidulans Ar as to modulate hyphal morphogenesis and asexual development.