HYP1, A HYDROPHOBIN GENE FROM ASPERGILLUS-FUMIGATUS, COMPLEMENTS THE RODLETLESS PHENOTYPE IN ASPERGILLUS-NIDULANS

Aspergillus fumigatus produces conidia that are highly dispersable and resistant to degradation. We have sought to analyze these properties by studying the rodlets which form the outer spore coat protein. Degen erate primers based on hydrophobins in other fungi were applied to gen omic DNA from A. fumigatus in PCR. A product of this reaction with sim ilarity to an Aspergillus nidulans gene as judged by Southern hybridiz ation was chosen for further study. Cloning and sequencing revealed a gene with two introns which encodes a protein of 159 amino acids. Stru ctural characteristics consistent with those of other fungal hydrophob in genes, especially conserved cysteine residues, are present. The exp ression of the gene is limited to the developmental stages in which ma turing conidiophores are present. This A. fumigatus gene, HYP1, was us ed to transform a mutant strain of A. nidulans that lacks rodlets. Tra nsformants,vith a single copy of HYP1 expressed a rodlet layer on thei r conidia as observed by freeze-fracture electron microscopy.