Overexpression of a dominant-negative allele of YPT1 inhibits growth and aspartyl protease secretion in Candida albicans

S. A. Lee, Y. Mao, Z. Zhang, Brian Wong

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

To investigate the pre-Golgi secretion pathway in the pathogenic yeast Candida albicans, we cloned the C. albicans homologue of the Saccharomyces cerevisiae protein secretion gene YPT1. The C. albicans YPT1 ORF contained a 624 bp intronless ORF encoding a deduced protein of 207 aa and 2.3 kDa. This deduced protein was 77% identical to S. cerevisiae Ypt1 protein (Ypt1p) and it contained GTP-binding domains that are conserved among all known ras-like GTPases. Multicopy plasmids containing C. albicans YPT1 complemented the temperature-sensitive S. cerevisiae ypt1 (A136D) mutation. One chromosomal YPT1 allele in C. albicans CAI4 was readily disrupted by homologous gene targeting, but attempts to disrupt the second allele yielded no viable null mutants. Since this suggested that C. albicans YPT1 may be essential, a mutant ypt1 allele was constructed encoding the amino acid substitution analogous to the N121I substitution in a known trans-dominant inhibitor of S. cerevisiae Ypt1p. Next, a GAL1-regulated plasmid was used to express the mutant ypt1(N121I) allele in C. albicans CAI4. Ten of 11 transformants tested grew normally in glucose and poorly in galactose, and plasmid curing restored growth to wild-type levels. When these transformants were incubated in galactose, secretion of aspartyl proteinase (Sap) was inhibited and membrane-bound secretory vesicles accumulated intracellularly. These results imply that C. albicans YPT1 is required for growth and protein secretion, and they confirm the feasibility of using inducible dominant-negative alleles to define the functions of essential genes in C. albicans.

Original languageEnglish (US)
Pages (from-to)1961-1970
Number of pages10
JournalMicrobiology
Volume147
Issue number7
StatePublished - 2001
Externally publishedYes

Fingerprint

Aspartic Acid Proteases
Candida albicans
Alleles
Growth
Saccharomyces cerevisiae Proteins
Plasmids
Galactose
Open Reading Frames
ras Proteins
Proteins
Gene Targeting
Secretory Pathway
Essential Genes
Secretory Vesicles
Amino Acid Substitution
Guanosine Triphosphate
Saccharomyces cerevisiae
Yeasts
Glucose
Mutation

Keywords

  • Candida albicans
  • Protein secretion
  • Vesicle trafficking
  • YPT1

ASJC Scopus subject areas

  • Microbiology

Cite this

Overexpression of a dominant-negative allele of YPT1 inhibits growth and aspartyl protease secretion in Candida albicans. / Lee, S. A.; Mao, Y.; Zhang, Z.; Wong, Brian.

In: Microbiology, Vol. 147, No. 7, 2001, p. 1961-1970.

Research output: Contribution to journalArticle

Lee, S. A. ; Mao, Y. ; Zhang, Z. ; Wong, Brian. / Overexpression of a dominant-negative allele of YPT1 inhibits growth and aspartyl protease secretion in Candida albicans. In: Microbiology. 2001 ; Vol. 147, No. 7. pp. 1961-1970.
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