Essential genes encoded by the mating-type locus of the human fungal pathogen Cryptococcus neoformans

ABSTRACT Fungal sexual reproduction is controlled by the mating-type (MAT) locus. In contrast to a majority of species in the phylum Basidiomycota that have tetrapolar mating-type systems, the opportunistic human pathogen Cryptococcus neoformans employs a bipolar mating-type system, with two mating...

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Main Authors: Zhuyun Bian, Ziyan Xu, Anushka Peer, Yeseul Choi, Shelby J. Priest, Konstantina Akritidou, Ananya Dasgupta, Tim A. Dahlmann, Ulrich Kück, Minou Nowrousian, Matthew S. Sachs, Sheng Sun, Joseph Heitman
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Language:English
Published: American Society for Microbiology 2025-04-01
Series:mBio
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Online Access:https://journals.asm.org/doi/10.1128/mbio.00223-25
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author Zhuyun Bian
Ziyan Xu
Anushka Peer
Yeseul Choi
Shelby J. Priest
Konstantina Akritidou
Ananya Dasgupta
Tim A. Dahlmann
Ulrich Kück
Minou Nowrousian
Matthew S. Sachs
Sheng Sun
Joseph Heitman
author_facet Zhuyun Bian
Ziyan Xu
Anushka Peer
Yeseul Choi
Shelby J. Priest
Konstantina Akritidou
Ananya Dasgupta
Tim A. Dahlmann
Ulrich Kück
Minou Nowrousian
Matthew S. Sachs
Sheng Sun
Joseph Heitman
author_sort Zhuyun Bian
collection DOAJ
description ABSTRACT Fungal sexual reproduction is controlled by the mating-type (MAT) locus. In contrast to a majority of species in the phylum Basidiomycota that have tetrapolar mating-type systems, the opportunistic human pathogen Cryptococcus neoformans employs a bipolar mating-type system, with two mating types (a and α) determined by a single MAT locus that is unusually large (~120 kb) and contains more than 20 genes. While several MAT genes are associated with mating and sexual development, others control conserved cellular processes (e.g., cargo transport and protein synthesis), of which five (MYO2, PRT1, RPL22, RPL39, and RPO41) have been hypothesized to be essential. In this study, through genetic analysis involving sporulation of heterozygous diploid deletion mutants, as well as in some cases construction and analyses of conditional expression alleles of these genes, we confirmed that with the exception of MYO2, both alleles of the other four MAT genes are indeed essential for cell viability. We further showed that while MYO2 is not essential, its function is critical for infectious spore production, faithful cytokinesis, adaptation for growth at high temperature, and pathogenicity in vivo. Our results demonstrate the presence of essential genes in the MAT locus that are divergent between cells of opposite mating types. We discuss possible mechanisms to maintain functional alleles of these essential genes in a rapidly evolving genomic region in the context of fungal sexual reproduction and mating-type evolution.IMPORTANCESexual reproduction is essential for long-term evolutionary success. Fungal cell-type identity is governed by the MAT locus, which is typically rapidly evolving and highly divergent between different mating types. In this study, we show that the a and α alleles of four genes encoded in the MAT locus of the opportunistic human fungal pathogen C. neoformans are essential. We demonstrate that a fifth gene, MYO2, which had been predicted to be essential, is in fact dispensable for cell viability. However, a functional MYO2 allele is important for cytokinesis and fungal pathogenicity. Our study highlights the need for careful genetic analyses in determining essential genes, which is complementary to high-throughput approaches. Additionally, the presence of essential genes in the MAT locus of C. neoformans provides insights into the function, maintenance, and evolution of these fast-evolving genomic regions.
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spelling doaj-art-98cc2087da3545c496c25bc4d96b3f9c2025-08-20T02:16:29ZengAmerican Society for MicrobiologymBio2150-75112025-04-0116410.1128/mbio.00223-25Essential genes encoded by the mating-type locus of the human fungal pathogen Cryptococcus neoformansZhuyun Bian0Ziyan Xu1Anushka Peer2Yeseul Choi3Shelby J. Priest4Konstantina Akritidou5Ananya Dasgupta6Tim A. Dahlmann7Ulrich Kück8Minou Nowrousian9Matthew S. Sachs10Sheng Sun11Joseph Heitman12Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USADepartment of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USADepartment of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USADepartment of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USADepartment of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USADepartment of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USADepartment of Biology, Texas A&M University, College Station, Texas, USAAllgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Bochum, GermanyAllgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Bochum, GermanyLehrstuhl für Molekulare und Zelluläre Botanik, Ruhr-Universität Bochum, Bochum, GermanyDepartment of Biology, Texas A&M University, College Station, Texas, USADepartment of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USADepartment of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USAABSTRACT Fungal sexual reproduction is controlled by the mating-type (MAT) locus. In contrast to a majority of species in the phylum Basidiomycota that have tetrapolar mating-type systems, the opportunistic human pathogen Cryptococcus neoformans employs a bipolar mating-type system, with two mating types (a and α) determined by a single MAT locus that is unusually large (~120 kb) and contains more than 20 genes. While several MAT genes are associated with mating and sexual development, others control conserved cellular processes (e.g., cargo transport and protein synthesis), of which five (MYO2, PRT1, RPL22, RPL39, and RPO41) have been hypothesized to be essential. In this study, through genetic analysis involving sporulation of heterozygous diploid deletion mutants, as well as in some cases construction and analyses of conditional expression alleles of these genes, we confirmed that with the exception of MYO2, both alleles of the other four MAT genes are indeed essential for cell viability. We further showed that while MYO2 is not essential, its function is critical for infectious spore production, faithful cytokinesis, adaptation for growth at high temperature, and pathogenicity in vivo. Our results demonstrate the presence of essential genes in the MAT locus that are divergent between cells of opposite mating types. We discuss possible mechanisms to maintain functional alleles of these essential genes in a rapidly evolving genomic region in the context of fungal sexual reproduction and mating-type evolution.IMPORTANCESexual reproduction is essential for long-term evolutionary success. Fungal cell-type identity is governed by the MAT locus, which is typically rapidly evolving and highly divergent between different mating types. In this study, we show that the a and α alleles of four genes encoded in the MAT locus of the opportunistic human fungal pathogen C. neoformans are essential. We demonstrate that a fifth gene, MYO2, which had been predicted to be essential, is in fact dispensable for cell viability. However, a functional MYO2 allele is important for cytokinesis and fungal pathogenicity. Our study highlights the need for careful genetic analyses in determining essential genes, which is complementary to high-throughput approaches. Additionally, the presence of essential genes in the MAT locus of C. neoformans provides insights into the function, maintenance, and evolution of these fast-evolving genomic regions.https://journals.asm.org/doi/10.1128/mbio.00223-25mating-type locusCryptococcus neoformansmolecular geneticsessential genespathogenicity
spellingShingle Zhuyun Bian
Ziyan Xu
Anushka Peer
Yeseul Choi
Shelby J. Priest
Konstantina Akritidou
Ananya Dasgupta
Tim A. Dahlmann
Ulrich Kück
Minou Nowrousian
Matthew S. Sachs
Sheng Sun
Joseph Heitman
Essential genes encoded by the mating-type locus of the human fungal pathogen Cryptococcus neoformans
mBio
mating-type locus
Cryptococcus neoformans
molecular genetics
essential genes
pathogenicity
title Essential genes encoded by the mating-type locus of the human fungal pathogen Cryptococcus neoformans
title_full Essential genes encoded by the mating-type locus of the human fungal pathogen Cryptococcus neoformans
title_fullStr Essential genes encoded by the mating-type locus of the human fungal pathogen Cryptococcus neoformans
title_full_unstemmed Essential genes encoded by the mating-type locus of the human fungal pathogen Cryptococcus neoformans
title_short Essential genes encoded by the mating-type locus of the human fungal pathogen Cryptococcus neoformans
title_sort essential genes encoded by the mating type locus of the human fungal pathogen cryptococcus neoformans
topic mating-type locus
Cryptococcus neoformans
molecular genetics
essential genes
pathogenicity
url https://journals.asm.org/doi/10.1128/mbio.00223-25
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