A genome sequence survey shows that the pathogenic yeast Candida parapsilosis has a defective MTLa1 allele at its mating type locus.
Candida parapsilosis is responsible for ca. 15% of Candida infections and is of particular concern in neonates and surgical intensive care patients. The related species Candida albicans has recently been shown to possess a functional mating pathway. To analyze the analogous pathway in C. parapsilosis, we carried out a genome sequence survey of the type strain. We identified ca. 3,900 genes, with an average amino acid identity of 59% with C. albicans. Of these, 23 are predicted to be predominantly involved in mating. We identified a genomic locus homologous to the MTLa mating type locus of C. albicans, but the C. parapsilosis type strain has at least two internal stop codons in the MTLa1 open reading frame, and two predicted introns are not spliced. These stop codons were present in MTLa1 of all eight C. parapsilosis isolates tested. Furthermore, we found that all isolates of C. parapsilosis tested appear to contain only the MTLa idiomorph at the presumptive mating locus, unlike C. albicans and C. dubliniensis. MTLalpha sequences are present but at a different chromosomal location. It is therefore likely that all (or at least the majority) of C. parapsilosis isolates have a mating pathway that is either defective or substantially different from that of C. albicans.
Logue
Mary E
ME
Department of Biochemistry, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
Wong
Simon
S
Wolfe
Kenneth H
KH
Butler
Geraldine
G
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D002175:Candida / Q000235:genetics* / Q000472:pathogenicity*; D015825:Chromosomes, Fungal; D018388:Codon, Terminator; D004271:DNA, Fungal / Q000737:chemistry; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D016681:Genome, Fungal; D007438:Introns; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011544:Pseudogenes; D012326:RNA Splicing; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid
D018388:Codon, Terminator; D004271:DNA, Fungal