Characterization of the Zinc cluster transcription factor: the role in the amino acid uptake pathway in Cryptococcus neoformans and its relationship to virulence

• Grant number: 21/14632-5
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): August 01, 2022
• Effective date (End): June 30, 2024
• Field of knowledge: Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
• Principal Investigator: Renata Castiglioni Pascon
• Grantee: Mateus Possari de Oliveira
• Host Institution: Instituto de Ciências Ambientais, Químicas e Farmacêuticas (ICAQF). Universidade Federal de São Paulo (UNIFESP). Campus Diadema. Diadema , SP, Brazil

Abstract

Invasive Fungal Infections (IFIs) are caused by opportunistic pathogens like the basidiomycete fungus Cryptococcus neoformans. These infections mainly affect immunocompromised individuals, spreading to several body sites, including the central nervous system, causing fungal meningitis, a disease with a high mortality rate. Cryptococcosis is difficult to treat, because drugs available on the market have low selective toxicity and numerous side effects. Several studies seek to understand the biology of this yeast, its virulence factors, its interactions with the host and new forms of treatment. The Cryptococcus group from the Laboratory of Microbial Interactions at UNIFESP (LIMIc) demonstrated that amino acid permeases are essential for the survival and virulence of C. neoformans. The expression of these transporters is, in part, under the control of the Ras1 signaling pathway. The Ras1 deletion reduced the transcription of several genes encoding amino acid permeases in C. neoformans, but the mechanism behind this has not been elucidated. In S. cerevisiae, the Msi1 protein attenuates Ras/cAMP signaling. Previous literature demonstrated that, in C. neoformans, MSL1 has pleiotropic effects on melanin production, sexual differentiation, thermotolerance, stress response and antifungal resistance. Our previous studies demonstrated that Msl1 acts as a negative regulator of Ras in response to amino acids, as the expression of the permease genes was induced in the ”msl1 lineage compared to the wild type. Furthermore, Msl1 is part of the subtelomeric gene silencing polycomb complex. Literature data and our own data demonstrated that Msl1 negatively regulates the expression of a subtelomeric gene encoding a Zinc cluster-type transcription factor (CNAG_05333) not yet described in basidiomycetes. Our transcriptome analyzes indicate that this transcription factor is induced in nutritional mutants. Therefore, this master's work aims to test the hypothesis that the negative attenuator of Ras1 (Msl1) controls the expression of the transcription factor CNAG_05333, which in turn controls the expression of amino acid permeases. Even more broadly, this research project will seek to establish the role of this Zinc cluster transcription factor in the response to nutritional stress and virulence of C. neoformans.