Conserved factors Ryp2 and Ryp3 control cell morphology and infectious spore formation in the fungal pathogen

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Efficient Sporulation of Saccharomyces cerevisiae in a 96 Multiwell Format
08:54

Efficient Sporulation of Saccharomyces cerevisiae in a 96 Multiwell Format

Published on: September 17, 2016

Rachael Hanby Webster1, Anita Sil

  • 1Department of Microbiology and Immunology, University of California, San Francisco, CA 94143-0414, USA.

Proceedings of the National Academy of Sciences of the United States of America
|September 16, 2008
PubMed

Insights

Two new genes, RYP2 and RYP3, are crucial for the pathogenic yeast form of Histoplasma capsulatum. These genes regulate temperature-dependent growth and spore production, impacting fungal development.

Area of Science:

  • Mycology
  • Molecular Biology
  • Pathogenesis

Background:

  • Histoplasma capsulatum is a dimorphic fungal pathogen causing histoplasmosis.
  • Temperature transition from filamentous to yeast form is critical for H. capsulatum virulence.
  • Regulatory mechanisms controlling this dimorphism are not fully understood.

Purpose of the Study:

  • To identify and characterize novel genes involved in the temperature-dependent dimorphism of H. capsulatum.
  • To elucidate the role of these genes in both yeast-phase growth and sporulation.

Main Methods:

  • Gene identification and knockout mutant generation in H. capsulatum.
  • Analysis of gene expression using quantitative PCR.
  • Phenotypic characterization of wild-type and mutant strains under different temperature conditions.

Main Results:

  • RYP2 and RYP3 genes were identified as essential for yeast-phase growth.
  • Mutants lacking RYP2 or RYP3 exhibit constitutive filamentous growth at all temperatures.
  • RYP2 and RYP3 are upregulated at 37°C and are involved in regulating sporulation at room temperature.
  • RYP1, RYP2, and RYP3 exhibit a co-regulatory relationship for temperature-dependent gene expression.

Conclusions:

  • RYP2 and RYP3 are key regulators of H. capsulatum dimorphism, responding to host temperature.
  • These genes play a dual role in promoting yeast-phase growth and regulating sporulation.
  • The findings reveal a conserved regulatory pathway analogous to fungal Velvet A proteins, but temperature-responsive in H. capsulatum.

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