The isolation of FOS-1, a gene encoding a putative two-component histidinekinase from Aspergillus fumigatus

The isolation of FOS-1, a gene encoding a putative two-component histidine kinase from Aspergillus fumigatus, Fungal Genetics and Biology 31, 55- 67, In fungi, two-component histidine kinases are involved in response mechanis ms to extracellular changes in osmolarity, resistance to dicarboximide fung icides, and cell-wall assembly. in the human opportunistic fungus, Candida albicans, each of the three histidine kinases plays a role in virulence, He re, we identify, for the first time, a gene, FOS-1, from the human pathogen ic fungus Aspergillus fumigatus that predicts a protein with homology to tw o-component histidine kinases, The predicted FOS-1 protein is highly homolo gous to bacterial and other fungal histidine kinases in several functional domains, but is divergent at the amino- and carboxy-termini. A mutant lacki ng the FOS-1 locus, Delta FOS-1, did not exhibit a detectable defect in eit her hyphal growth or morphology when grown on solid or liquid medium. Howev er, in liquid medium, conidiophore development of the Delta FOS-1 mutant wa s delayed. Compared to wild type, the Delta FOS-1 strain was neither osmoti cally sensitive nor sensitive or resistant to a number of nondi-carboximide antifungal drugs, but was highly resistant to dicarboximide fungicides and resistant to novozym 234, suggesting that FOS-1p may play a role in the re gulation of cell-wall assembly. (C) 2000 Academic Press.