title: Multiplication of an ancestral gene encoding secreted fungalysin preceded species differentiation in the dermatophytes Trichophyton and Microsporum.
abstract: Dermatophytes are human and animal pathogenic fungi which cause cutaneous infections and grow exclusively in the stratum corneum, nails and hair. In a culture medium containing soy proteins as sole nitrogen source a substantial proteolytic activity was secreted by Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis. This proteolytic activity was 55-75 % inhibited by o-phenanthroline, attesting that metalloproteases were secreted by all three species. Using a consensus probe constructed on previously characterized genes encoding metalloproteases (MEP) of the M36 fungalysin family in Aspergillus fumigatus, Aspergillus oryzae and M. canis, a five-member MEP family was isolated from genomic libraries of T. rubrum, T. mentagrophytes and M. canis. A phylogenetic analysis of genomic and protein sequences revealed a robust tree consisting of five main clades, each of them including a MEP sequence type from each dermatophyte species. Each MEP type was remarkably conserved across species (72-97 % amino acid sequence identity). The tree topology clearly indicated that the multiplication of MEP genes in dermatophytes occurred prior to species divergence. In culture medium containing soy proteins as a sole nitrogen source secreted Meps accounted for 19-36 % of total secreted protein extracts; characterization of protein bands by proteolysis and mass spectrometry revealed that the three dermatophyte species secreted two Meps (Mep3 and Mep4) encoded by orthologous genes.
authors.affiliation: Dermatology Service (DHURDV), Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Olivier
authors.initials: O
authors.lastname: Jousson
authors.affiliation: Dermatology Service (DHURDV), Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Léchenne
authors.affiliation: Dermatology Service (DHURDV), Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Olympia
authors.initials: O
authors.lastname: Bontems
authors.affiliation: Dermatology Service (DHURDV), Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Capoccia
authors.affiliation: Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, Belgium.
authors.forename: Bernard
authors.initials: B
authors.lastname: Mignon
authors.affiliation: Protein Analysis Facility, Institute of Biochemistry, University of Lausanne, Epalinges, Switzerland.
authors.forename: Jachen
authors.initials: J
authors.lastname: Barblan
authors.affiliation: Protein Analysis Facility, Institute of Biochemistry, University of Lausanne, Epalinges, Switzerland.
authors.forename: Manfredo
authors.initials: M
authors.lastname: Quadroni
authors.affiliation: Dermatology Service (DHURDV), Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Michel
authors.initials: M
authors.lastname: Monod
mesh_terms: D001230:Aspergillus / Q000201:enzymology / Q000235:genetics; D001483:Base Sequence; D017931:DNA Primers; D003881:Dermatomycoses / Q000382:microbiology; D005656:Fungal Proteins / Q000235:genetics; D006801:Humans; D016013:Likelihood Functions; D013058:Mass Spectrometry; D045726:Metalloproteases / Q000235:genetics*; D008864:Microsporum / Q000145:classification / Q000235:genetics* / Q000254:growth & development; D010802:Phylogeny; D014005:Tinea / Q000382:microbiology; D014249:Trichophyton / Q000145:classification / Q000235:genetics* / Q000254:growth & development
chemical_list: D017931:DNA Primers; D005656:Fungal Proteins; D045726:Metalloproteases