title: Cloning of the RHO1 gene from Candida albicans and its regulation of beta-1,3-glucan synthesis.
abstract: The Saccharomyces cerevisiae RHO1 gene encodes a low-molecular-weight GTPase. One of its recently identified functions is the regulation of beta-1,3-glucan synthase, which synthesizes the main component of the fungal cell wall (J. Drgonova et al., Science 272:277-279, 1996; T. Mazur and W. Baginsky, J. Biol. Chem. 271:14604-14609, 1996; and H. Qadota et al., Science 272:279-281, 1996). From the opportunistic pathogenic fungus Candida albicans, we cloned the RHO1 gene by the PCR and cross-hybridization methods. Sequence analysis revealed that the Candida RHO1 gene has a 597-nucleotide region which encodes a putative 22.0-kDa peptide. The deduced amino acid sequence predicts that Candida albicans Rho1p is 82.9% identical to Saccharomyces Rho1p and contains all the domains conserved among Rho-type GTPases from other organisms. The Candida albicans RHO1 gene could rescue a S. cerevisiae strain containing a rho1 deletion. Furthermore, recombinant Candida albicans Rho1p could reactivate the beta-1,3-glucan synthesis activities of both C. albicans and S. cerevisiae membranes in which endogenous Rho1p had been depleted by Tergitol NP-40-NaCl treatment. Candida albicans Rho1p was copurified with the beta-1,3-glucan synthase putative catalytic subunit, Candida albicans Gsc1p, by product entrapment. Candida albicans Rho1p was shown to interact directly with Candida albicans Gsc1p in a ligand overlay assay and a cross-linking study. These results indicate that Candida albicans Rho1p acts in the same manner as Saccharomyces cerevisiae Rho1p to regulate beta-1,3-glucan synthesis.
authors.affiliation: Department of Mycology, Nippon Roche Research Center, Kamakura, Kanagawa, Japan. osamu.kondoh@roche.com
authors.forename: O
authors.initials: O
authors.lastname: Kondoh
authors.forename: Y
authors.initials: Y
authors.lastname: Tachibana
authors.forename: Y
authors.initials: Y
authors.lastname: Ohya
authors.forename: M
authors.initials: M
authors.lastname: Arisawa
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002176:Candida albicans / Q000235:genetics*; D003001:Cloning, Molecular; D003432:Cross-Linking Reagents; D019204:GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D005936:Glucans / Q000096:biosynthesis*; D005964:Glucosyltransferases / Q000378:metabolism*; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D047071:beta-Glucans; D020741:rho GTP-Binding Proteins
chemical_list: D003432:Cross-Linking Reagents; D005936:Glucans; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D047071:beta-Glucans; C033363:beta-1,3-glucan; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase; D019204:GTP-Binding Proteins; C051302:RHO1 protein, S cerevisiae; D020741:rho GTP-Binding Proteins; C511156:rho1 protein, S pombe