ABSTRACT
Proper morphology is essential for the ability of Candida albicans to switch between yeast and hyphae and thereby sustain its virulence. Here we identified, by differential screening, a novel C. albicans AAA ATPase encoding gene, CaYLL34 (RIX7), with enhanced expression in hyphae. Phylogenetic analysis suggests that CaYLL34 belongs to a [quot ]VCP-like[quot ] subgroup of AAA ATPases essential for yeast viability and contains a bipartite nuclear localization signal. Inactivation of one copy of CaYLL34, by the URA-Blaster method, generated the heterozygous mutant strain M61. This strain has severe phenotypic alterations, such as a highly increased vacuole, abnormal cell shape and reduced growth in different conditions. Also, major pathogenicity factors are affected in M61, for instance, a significant decrease of hypha formation (>90%), surface biofilm adhesion (86%) and secreted aspartyl proteinase activity (76.5%). Our results show that the partial impairment of CaYll34p cellular levels is sufficient to affect the proper cellular morphology and pathogenicity factors and suggest that this protein is required for biogenesis of ribosomal subunits. Accordingly, we propose that the product of CaYLL34 could be tested as a novel target for antifungal drugs.
Subject(s)
Adenosine Triphosphatases/genetics , Biofilms/growth & development , Candida albicans/genetics , Aspartic Acid Endopeptidases/metabolism , Saccharomyces cerevisiae Proteins/genetics , Base Sequence , Candida albicans/enzymology , Candida albicans/growth & development , Hyphae/enzymology , Hyphae/genetics , Hyphae/growth & development , Molecular Sequence Data , Mutation , Phylogeny , Reverse Transcriptase Polymerase Chain Reaction , Sequence Analysis, DNAABSTRACT
The present study was designed to identify alkaline phosphatases in non-permeabilized hyphal cells of the fungus Neurospora crassa by staining these enzymatic activities with a modified azo dye coupling method. Our strategy allowed the identification of three non-specific alkaline phosphatase activities, one of them possibly being a novel putative enzyme, which is not responsive to either Mg2+ or EDTA. Another alkaline phosphatase activity, whose location in the hyphal cell is regulated by phosphate, is stimulated by Mg2+, inhibited by EDTA, and somehow dependent on the expression of the pho-2+-encoded Pi-repressible alkaline phosphatase.