Functional analysis of the phospholipase C gene CaPLC1 and two unusual phospholipase C genes, CaPLC2 and CaPLC3, of Candida albicans.
Phospholipases C are known to be important regulators of cellular processes but may also act as virulence factors of pathogenic microbes. At least three genes in the genome of the human-pathogenic fungus Candida albicans encode phospholipases with conserved phospholipase C (Plc) motifs. None of the deduced protein sequences contain N-terminal signal peptides, suggesting that these phospholipases are not secreted. In contrast to its orthologue in Sacharomyces cerevisiae, CaPLC1 seems to be an essential gene. However, a conditional mutant with reduced transcript levels of CaPLC1 had phenotypes similar to Plc1p-deficient mutants in S. cerevisiae, including reduced growth on media causing increased osmotic stress, on media with a non-glucose carbon source, or at elevated or lower temperatures, suggesting that CaPlc1p, like the Plc1p counterpart in S. cerevisiae, may be involved in multiple cellular processes. Furthermore, phenotypic screening of the heterozygous DeltaCaplc1/CaPLC1 mutant showed additional defects in hyphal formation. The loss of CaPLC1 cannot be compensated by two additional PLC genes of C. albicans (CaPLC2 and CaPLC3) encoding two almost identical phospholipases C with no counterpart in S. cerevisiae but containing structural elements found in bacterial phospholipases C. Although the promoter sequences of CaPLC2 and CaPLC3 differed dramatically, the transcriptional pattern of both genes was similar. In contrast to CaPLC1, CaPLC2 and CaPLC3 are not essential. Although Caplc2/3 mutants had reduced abilities to produce hyphae on solid media, these mutants were as virulent as the wild-type in a model of systemic infection. These data suggest that C. albicans contains two different classes of phospholipases C which are involved in cellular processes but which have no specific functions in pathogenicity.
Kunze
Donika
D
Robert Koch-Institut, Nordufer 20, D-13353, Berlin, Germany.
Melzer
Inga
I
Molecular Phytopathology and Genetics, University of Hamburg, Biocenter Klein Flottbek, Ohnhorststr. 18, D-22609 Hamburg, Germany.
Bennett
Désirée
D
Microbiology Research Division, School of Dental Science, University of Dublin, Trinity College, Dublin 2, Republic of Ireland.
Sanglard
Dominique
D
Institut de Microbiologie, Centre Hospitalier Universitaire Vaudois, CH-1011 Lausanne, Switzerland.
MacCallum
Donna
D
Aberdeen Fungal Group, School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK.
Nörskau
Jan
J
Molecular Phytopathology and Genetics, University of Hamburg, Biocenter Klein Flottbek, Ohnhorststr. 18, D-22609 Hamburg, Germany.
Coleman
David C
DC
Microbiology Research Division, School of Dental Science, University of Dublin, Trinity College, Dublin 2, Republic of Ireland.
Odds
Frank C
FC
Aberdeen Fungal Group, School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK.
Schäfer
Wilhelm
W
Molecular Phytopathology and Genetics, University of Hamburg, Biocenter Klein Flottbek, Ohnhorststr. 18, D-22609 Hamburg, Germany.
Hube
Bernhard
B
Robert Koch-Institut, Nordufer 20, D-13353, Berlin, Germany.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002176:Candida albicans / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D002177:Candidiasis / Q000382:microbiology / Q000503:physiopathology; D029721:Drosophila Proteins; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic; D010738:Type C Phospholipases / Q000737:chemistry / Q000145:classification* / Q000235:genetics / Q000378:metabolism*
D029721:Drosophila Proteins; D005656:Fungal Proteins; D017346:Protein Serine-Threonine Kinases; D010738:Type C Phospholipases