A unique aspartyl protease gene expansion in Talaromyces marneffei plays a role in growth inside host phagocytes

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Aspartyl proteases are crucial proteolytic enzymes in eukaryotes and retroviruses, often linked to microbial pathogenicity.
• The fungus Talaromyces marneffei exhibits a significant expansion of aspartyl protease genes, prompting further investigation.

Purpose of the Study:

• To characterize the expansion of aspartyl protease genes (pop) in Talaromyces marneffei.
• To elucidate the role of these genes in the fungus's pathogenicity and intracellular growth.

Main Methods:

• Genomic analyses to identify and characterize the expanded gene family.
• Computational and molecular approaches to study gene expression, protein localization, and functional effects.
• Macrophage infection models to assess yeast cell formation and intracellular growth.

Main Results:

• The Talaromyces marneffei aspartyl protease gene family (pop) shows copy number variation and positive selection.
• Differential gene expression was observed, with some pop genes expressed during intracellular growth.
• These proteases exhibit distinct localization patterns and influence yeast cell formation through additive and epistatic effects.

Conclusions:

• The expanded aspartyl protease gene family in Talaromyces marneffei is a recent evolutionary development.
• These genes play a significant role in the fungus's intracellular growth and contribute to its overall pathogenicity.