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O'Meara TR. Going fishing: how to get what you want from a fungal genetic screen. mSphere 2024:e0063823. [PMID: 38958459 DOI: 10.1128/msphere.00638-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024] Open
Abstract
Five years ago, as I was starting my lab, I wrote about two functional genomic screens in fungi that had inspired me (mSphere 4:e00299-19, https://doi.org/10.1128/mSphere.00299-19). Now, I want to discuss some of the principles and questions that I ask myself and my students as we embark on our own screens. A good screen, whether it is a genetic or chemical screen, can be the starting point for new discovery and an excellent basis for the beginning of a scientific research project. However, screens are often criticized for being "fishing expeditions." To stretch this metaphor to the extreme, this is because people are worried that we do not know how to fish, that we will come home without any fish, bring home the wrong fish, or not know what to do with a fish if we caught it. How you set up the screen and analyze the results determines whether the screen will be useful. In this mini-review, and in the spirit of teaching a scientist to fish, I will discuss recent excellent fungal genetic and chemical screens that illustrate some of the key aspects of a successful screen.
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Affiliation(s)
- Teresa R O'Meara
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
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2
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Gaylord EA, Choy HL, Chen G, Briner SL, Doering TL. Sac1 links phosphoinositide turnover to cryptococcal virulence. mBio 2024:e0149624. [PMID: 38953635 DOI: 10.1128/mbio.01496-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 05/24/2024] [Indexed: 07/04/2024] Open
Abstract
Cryptococcus neoformans is an environmentally acquired fungal pathogen that causes over 140,000 deaths per year. Cryptococcal infection occurs when infectious particles are deposited into the lung, where they encounter host phagocytic cells. C. neoformans may be engulfed by these phagocytes, an important step of infection that leads to outcomes ranging from termination of infection to cryptococcal dissemination. To study this critical process, we screened approximately 4,700 cryptococcal gene deletion mutants for altered uptake, using primary mouse and human phagocytic cells. Among the hits of these two screens, we identified 93 mutants with perturbed uptake in both systems, as well as others with differences in uptake by only one cell type. We further screened the hits for changes in thickness of the capsule, a protective polysaccharide layer around the cell which is an important cryptococcal virulence factor. The combination of our three screens yielded 45 mutants, including one lacking the phosphatidylinositol-4-phosphate phosphatase Sac1. In this work, we implicate Sac1 in both host cell uptake and capsule production. We found that sac1 mutants exhibit lipid trafficking defects, reductions in secretory system function, and changes in capsule size and composition. Many of these changes occur specifically in tissue culture media, highlighting the role of Sac1 phosphatase activity in responding to the stress of host-like conditions. Overall, these findings show how genome-scale screening can identify cellular factors that contribute to our understanding of cryptococcal biology and demonstrate the role of Sac1 in determining fungal virulence.IMPORTANCECryptococcus neoformans is a fungal pathogen with significant impact on global health. Cryptococcal cells inhaled from the environment are deposited into the lungs, where they first contact the human immune system. The interaction between C. neoformans and host cells is critical because this step of infection can determine whether the fungal cells die or proliferate within the human host. Despite the importance of this stage of infection, we have limited knowledge of cryptococcal factors that influence its outcome. In this study, we identify cryptococcal genes that affect uptake by both human and mouse cells. We also identify mutants with altered capsule, a protective coating that surrounds the cells to shield them from the host immune system. Finally, we characterize the role of one gene, SAC1, in these processes. Overall, this study contributes to our understanding of how C. neoformans interacts with and protects itself from host cells.
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Affiliation(s)
- Elizabeth A Gaylord
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hau Lam Choy
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Guohua Chen
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sydney L Briner
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Tamara L Doering
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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Gaylord EA, Choy HL, Chen G, Briner SL, Doering TL. Sac1 links phosphoinositide turnover to cryptococcal virulence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.18.576303. [PMID: 38293062 PMCID: PMC10827209 DOI: 10.1101/2024.01.18.576303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Cryptococcus neoformans is an environmentally-acquired fungal pathogen that causes over 140,000 deaths per year. Cryptococcal infection occurs when infectious particles are deposited into the lung, where they encounter host phagocytic cells. C. neoformans may be engulfed by these phagocytes, an important step of infection that leads to outcomes ranging from termination of infection to cryptococcal dissemination. To study this critical process, we screened approximately 4,700 cryptococcal gene deletion mutants for altered uptake, using primary mouse and human phagocytic cells. Among the hits of these two screens, we identified 93 mutants with perturbed uptake in both systems, as well as others with differences in uptake by only one cell type. We further screened the hits for changes in thickness of the capsule, a protective polysaccharide layer around the cell which is an important cryptococcal virulence factor. The combination of our three screens yielded 45 mutants, including one lacking the phosphatidylinositol-4-phosphate phosphatase Sac1. In this work, we implicate Sac1 in both host cell uptake and capsule production. We found that sac1 mutants exhibit lipid trafficking defects, reductions in secretory system function, and changes in capsule size and composition. Many of these changes occur specifically in tissue culture media, highlighting the role of Sac1 phosphatase activity in responding to the stress of host-like conditions. Overall, these findings show how genome-scale screening can identify cellular factors that contribute to our understanding of cryptococcal biology and demonstrate the role of Sac1 in determining fungal virulence. IMPORTANCE Cryptococcus neoformans is a fungal pathogen with significant impact on global health. Cryptococcal cells inhaled from the environment are deposited into the lungs, where they first contact the human immune system. The interaction between C. neoformans and host cells is critical because this step of infection can determine whether the fungal cells die or proliferate within the human host. Despite the importance of this stage of infection, we have limited knowledge of cryptococcal factors that influence its outcome. In this study, we identify cryptococcal genes that affect uptake by both human and mouse cells. We also identify mutants with altered capsule, a protective coating that surrounds the cells to shield them from the host immune system. Finally, we characterize the role of one gene, SAC1 , in these processes. Overall, this study contributes to our understanding of how C. neoformans interacts with and protects itself from host cells.
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Kwon S, Choi Y, Kim ES, Lee KT, Bahn YS, Jung KW. Pleiotropic roles of LAMMER kinase, Lkh1 in stress responses and virulence of Cryptococcus neoformans. Front Cell Infect Microbiol 2024; 14:1369301. [PMID: 38774630 PMCID: PMC11106425 DOI: 10.3389/fcimb.2024.1369301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 03/27/2024] [Indexed: 05/24/2024] Open
Abstract
Dual-specificity LAMMER kinases are highly evolutionarily conserved in eukaryotes and play pivotal roles in diverse physiological processes, such as growth, differentiation, and stress responses. Although the functions of LAMMER kinase in fungal pathogens in pathogenicity and stress responses have been characterized, its role in Cryptococcus neoformans, a human fungal pathogen and a model yeast of basidiomycetes, remains elusive. In this study, we identified a LKH1 homologous gene and constructed a strain with a deleted LKH1 and a complemented strain. Similar to other fungi, the lkh1Δ mutant showed intrinsic growth defects. We observed that C. neoformans Lkh1 was involved in diverse stress responses, including oxidative stress and cell wall stress. Particularly, Lkh1 regulates DNA damage responses in Rad53-dependent and -independent manners. Furthermore, the absence of LKH1 reduced basidiospore formation. Our observations indicate that Lkh1 becomes hyperphosphorylated upon treatment with rapamycin, a TOR protein inhibitor. Notably, LKH1 deletion led to defects in melanin synthesis and capsule formation. Furthermore, we found that the deletion of LKH1 led to the avirulence of C. neoformans in a systemic cryptococcosis murine model. Taken together, Lkh1 is required for the stress response, sexual differentiation, and virulence of C. neoformans.
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Affiliation(s)
- Sunhak Kwon
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk, Republic of Korea
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Yeseul Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Eui-Seong Kim
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, Jeonbuk, Republic of Korea
| | - Kyung-Tae Lee
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, Jeonbuk, Republic of Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Kwang-Woo Jung
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk, Republic of Korea
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Kang YS, Jung J, Brown H, Mateusiak C, Doering TL, Brent MR. How host-like signals drive gene expression and capsule expansion in Cryptococcus neoformans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.19.537239. [PMID: 37131703 PMCID: PMC10153387 DOI: 10.1101/2023.04.19.537239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen with a polysaccharide capsule that becomes greatly enlarged in the mammalian host and during in vitro growth under host-like conditions. To understand how individual environmental signals affect capsule size and gene expression, we grew cells in all combinations of five signals implicated in capsule size and systematically measured cell and capsule sizes. We also sampled these cultures over time and performed RNA-Seq in quadruplicate, yielding 881 RNA-Seq samples. Analysis of the resulting data sets showed that capsule induction in tissue culture medium, typically used to represent host-like conditions, requires the presence of either CO2 or exogenous cyclic AMP (cAMP). Surprisingly, adding either of these pushes overall gene expression in the opposite direction from tissue culture media alone, even though both are required for capsule development. Another unexpected finding was that rich medium blocks capsule growth completely. Statistical analysis further revealed many genes whose expression is associated with capsule thickness; deletion of one of these significantly reduced capsule size. Beyond illuminating capsule induction, our massive, uniformly collected dataset will be a significant resource for the research community.
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Affiliation(s)
- Yu Sung Kang
- These authors contributed equally
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110
- Department of Computer Science and Engineering, Washington University, St. Louis, MO 63108
| | - Jeffery Jung
- These authors contributed equally
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110
- Department of Computer Science and Engineering, Washington University, St. Louis, MO 63108
| | - Holly Brown
- Department of Computer Science and Engineering, Washington University, St. Louis, MO 63108
| | - Chase Mateusiak
- Department of Computer Science and Engineering, Washington University, St. Louis, MO 63108
| | - Tamara L. Doering
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Michael R. Brent
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110
- Department of Computer Science and Engineering, Washington University, St. Louis, MO 63108
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110
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Wang Y, Engel T, Teng X. Post-translational regulation of the mTORC1 pathway: A switch that regulates metabolism-related gene expression. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195005. [PMID: 38242428 DOI: 10.1016/j.bbagrm.2024.195005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 12/15/2023] [Accepted: 01/03/2024] [Indexed: 01/21/2024]
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) is a kinase complex that plays a crucial role in coordinating cell growth in response to various signals, including amino acids, growth factors, oxygen, and ATP. Activation of mTORC1 promotes cell growth and anabolism, while its suppression leads to catabolism and inhibition of cell growth, enabling cells to withstand nutrient scarcity and stress. Dysregulation of mTORC1 activity is associated with numerous diseases, such as cancer, metabolic disorders, and neurodegenerative conditions. This review focuses on how post-translational modifications, particularly phosphorylation and ubiquitination, modulate mTORC1 signaling pathway and their consequential implications for pathogenesis. Understanding the impact of phosphorylation and ubiquitination on the mTORC1 signaling pathway provides valuable insights into the regulation of cellular growth and potential therapeutic targets for related diseases.
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Affiliation(s)
- Yitao Wang
- College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, China; Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin D02 YN77, Ireland
| | - Tobias Engel
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin D02 YN77, Ireland; FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin D02 YN77, Ireland
| | - Xinchen Teng
- College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, China.
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Boodwa-Ko D, Doering TL. A Quick reCAP: Discovering Cryptococcus neoformans Capsule Mutants. J Fungi (Basel) 2024; 10:114. [PMID: 38392786 PMCID: PMC10889740 DOI: 10.3390/jof10020114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 02/24/2024] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that can cause severe meningoencephalitis in immunocompromised hosts and is a leading cause of death in HIV/AIDS patients. This pathogenic yeast is surrounded by a polysaccharide capsule that is critical for virulence and plays important roles in host-pathogen interactions. Understanding capsule biosynthesis is therefore key to defining the biology of C. neoformans and potentially discovering novel therapeutic targets. By exploiting methods to identify mutants deficient in capsule, June Kwon-Chung and other investigators have discovered numerous genes involved in capsule biosynthesis and regulation. Successful approaches have incorporated combinations of techniques including mutagenesis and systematic gene deletion; complementation and genetic screens; morphological examination, physical separation, and antibody binding; and computational modeling based on gene expression analysis. In this review, we discuss these methods and how they have been used to identify capsule mutants.
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Affiliation(s)
- Daphne Boodwa-Ko
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Tamara L Doering
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO 63110, USA
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Fidler E, Dwyer K, Ansari A. Ssu72: a versatile protein with functions in transcription and beyond. Front Mol Biosci 2024; 11:1332878. [PMID: 38304578 PMCID: PMC10830811 DOI: 10.3389/fmolb.2024.1332878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/08/2024] [Indexed: 02/03/2024] Open
Abstract
Eukaryotic transcription is a complex process involving a vast network of protein and RNA factors that influence gene expression. The main player in transcription is the RNA polymerase that synthesizes the RNA from the DNA template. RNA polymerase II (RNAPII) transcribes all protein coding genes and some noncoding RNAs in eukaryotic cells. The polymerase is aided by interacting partners that shuttle it along the gene for initiation, elongation and termination of transcription. One of the many factors that assist RNAPII in transcription of genes is Ssu72. It is a carboxy-terminal-domain (CTD)-phosphatase that plays pleiotropic roles in the transcription cycle. It is essential for cell viability in Saccharomyces cerevisiae, the organism in which it was discovered. The homologues of Ssu72 have been identified in humans, mice, plants, flies, and fungi thereby suggesting the evolutionarily conserved nature of the protein. Recent studies have implicated the factor beyond the confines of transcription in homeostasis and diseases.
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Affiliation(s)
| | | | - Athar Ansari
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
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Jung KW, Kwon S, Jung JH, Lim S, Bahn YS. Functional Characterization of DNA N-Glycosylase Ogg1 and Ntg1 in DNA Damage Stress of Cryptococcus neoformans. J Microbiol 2023; 61:981-992. [PMID: 38055144 DOI: 10.1007/s12275-023-00092-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 10/31/2023] [Indexed: 12/07/2023]
Abstract
Reactive oxygen species induce DNA strand breaks and DNA oxidation. DNA oxidation leads to DNA mismatches, resulting in mutations in the genome if not properly repaired. Homologous recombination (HR) and non-homologous end-joining (NHEJ) are required for DNA strand breaks, whereas the base excision repair system mainly repairs oxidized DNAs, such as 8-oxoguanine and thymine glycol, by cleaving the glycosidic bond, inserting correct nucleotides, and sealing the gap. Our previous studies revealed that the Rad53-Bdr1 pathway mainly controls DNA strand breaks through the regulation of HR- and NHEJ-related genes. However, the functional roles of genes involved in the base excision repair system remain elusive in Cryptococcus neoformans. In the present study, we identified OGG1 and NTG1 genes in the base excision repair system of C. neoformans, which are involved in DNA oxidation repair. The expression of OGG1 was induced in a Hog1-dependent manner under oxidative stress. On the other hand, the expression of NTG1 was strongly induced by DNA damage stress in a Rad53-independent manner. We demonstrated that the deletion of NTG1, but not OGG1, resulted in elevated susceptibility to DNA damage agents and oxidative stress inducers. Notably, the ntg1Δ mutant showed growth defects upon antifungal drug treatment. Although deletion of OGG1 or NTG1 did not increase mutation rates, the mutation profile of each ogg1Δ and ntg1Δ mutant was different from that of the wild-type strain. Taken together, we found that DNA N-glycosylase Ntg1 is required for oxidative DNA damage stress and antifungal drug resistance in C. neoformans.
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Affiliation(s)
- Kwang-Woo Jung
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea.
| | - Sunhak Kwon
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Jong-Hyun Jung
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea
| | - Sangyong Lim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea
- Department of Radiation Science, University of Science and Technology, Daejeon, 34113, Republic of Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
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Ren W, Zhang Y, Zhu M, Liu Z, Lian S, Wang C, Li B, Liu N. The Phosphatase Cascade Nem1/Spo7-Pah1 Regulates Fungal Development, Lipid Homeostasis, and Virulence in Botryosphaeria dothidea. Microbiol Spectr 2023; 11:e0388122. [PMID: 37191532 PMCID: PMC10269782 DOI: 10.1128/spectrum.03881-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 02/28/2023] [Indexed: 05/17/2023] Open
Abstract
Protein phosphatase complex Nem1/Spo7 plays crucial roles in the regulation of various biological processes in eukaryotes. However, its biological functions in phytopathogenic fungi are not well understood. In this study, genome-wide transcriptional profiling analysis revealed that Nem1 was significantly upregulated during the infection process of Botryosphaeria dothidea, and we identified and characterized the phosphatase complex Nem1/Spo7 and its substrate Pah1 (a phosphatidic acid phosphatase) in B. dothidea. Nem1/Spo7 physically interacted with and dephosphorylated Pah1 to promote triacylglycerol (TAG) and subsequent lipid droplet (LD) synthesis. Moreover, the Nem1/Spo7-dependently dephosphorylated Pah1 functioned as a transcriptional repressor of the key nuclear membrane biosynthesis genes to regulate nuclear membrane morphology. In addition, phenotypic analyses showed that the phosphatase cascade Nem1/Spo7-Pah1 was involved in regulating mycelial growth, asexual development, stress responses, and virulence of B. dothidea. IMPORTANCE Botryosphaeria canker and fruit rot caused by the fungus Botryosphaeria dothidea is one of the most destructive diseases of apple worldwide. Our data indicated that the phosphatase cascade Nem1/Spo7-Pah1 plays important roles in the regulation of fungal growth, development, lipid homeostasis, environmental stress responses, and virulence in B. dothidea. The findings will contribute to the in-depth and comprehensive understanding of Nem1/Spo7-Pah1 in fungi and the development of target-based fungicides for disease management.
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Affiliation(s)
- Weichao Ren
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Yihan Zhang
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Meiqi Zhu
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Zequn Liu
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Sen Lian
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Caixia Wang
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Baohua Li
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Na Liu
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
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Suo C, Gao Y, Ding C, Sun T. The function and regulation of heat shock transcription factor in Cryptococcus. Front Cell Infect Microbiol 2023; 13:1195968. [PMID: 37168390 PMCID: PMC10165103 DOI: 10.3389/fcimb.2023.1195968] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 04/10/2023] [Indexed: 05/13/2023] Open
Abstract
Cryptococcus species are opportunistic human fungal pathogens. Survival in a hostile environment, such as the elevated body temperatures of transmitting animals and humans, is crucial for Cryptococcus infection. Numerous intriguing investigations have shown that the Hsf family of thermotolerance transcription regulators plays a crucial role in the pathogen-host axis of Cryptococcus. Although Hsf1 is known to be a master regulator of the heat shock response through the activation of gene expression of heat shock proteins (Hsps). Hsf1 and other Hsfs are multifaceted transcription regulators that regulate the expression of genes involved in protein chaperones, metabolism, cell signal transduction, and the electron transfer chain. In Saccharomyces cerevisiae, a model organism, Hsf1's working mechanism has been intensively examined. Nonetheless, the link between Hsfs and Cryptococcus pathogenicity remains poorly understood. This review will focus on the transcriptional regulation of Hsf function in Cryptococcus, as well as potential antifungal treatments targeting Hsf proteins.
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Affiliation(s)
- Chenhao Suo
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Yiru Gao
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Chen Ding
- College of Life and Health Sciences, Northeastern University, Shenyang, China
- *Correspondence: Tianshu Sun, ; Chen Ding,
| | - Tianshu Sun
- Medical Research Center, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
- *Correspondence: Tianshu Sun, ; Chen Ding,
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12
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Jang EH, Kim JS, Yu SR, Bahn YS. Unraveling Capsule Biosynthesis and Signaling Networks in Cryptococcus neoformans. Microbiol Spectr 2022; 10:e0286622. [PMID: 36287085 PMCID: PMC9769619 DOI: 10.1128/spectrum.02866-22] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/29/2022] [Indexed: 01/09/2023] Open
Abstract
The polysaccharide capsule of Cryptococcus neoformans-an opportunistic basidiomycete pathogen and the major etiological agent of fungal meningoencephalitis-is a key virulence factor that prevents its phagocytosis by host innate immune cells. However, the complex signaling networks for their synthesis and attachment remain elusive. In this study, we systematically analyzed capsule biosynthesis and signaling networks using C. neoformans transcription factor (TF) and kinase mutant libraries under diverse capsule-inducing conditions. We found that deletion of GAT201, YAP1, BZP4, and ADA2 consistently caused capsule production defects in all tested media, indicating that they are capsule-regulating core TFs. Epistatic and expression analyses showed that Yap1 and Ada2 control Gat201 upstream, whereas Bzp4 and Gat201 independently regulate capsule production. Next, we searched for potential upstream kinases and found that mutants lacking PKA1, BUD32, POS5, IRE1, or CDC2801 showed reduced capsule production under all three capsule induction conditions, whereas mutants lacking HOG1 and IRK5 displayed enhanced capsule production. Pka1 and Irk5 controlled the induction of GAT201 and BZP4, respectively, under capsule induction conditions. Finally, we monitored the transcriptome profiles governed by Bzp4, Gat201, and Ada2 under capsule-inducing conditions and demonstrated that these TFs regulate redundant and unique sets of downstream target genes. Bzp4, Ada2, and Gat201 govern capsule formation in C. neoformans by regulating the expression of various capsule biosynthesis genes and chitin/chitosan synthesis genes in a positive and negative manner, respectively. In conclusion, this study provides further insights into the complex regulatory mechanisms of capsule production-related signaling pathways in C. neoformans. IMPORTANCE Over the past decades, human fungal pathogens, including C. neoformans, have emerged as a major public threat since the AIDS pandemic, only to gain more traction in connection to COVID-19. Polysaccharide capsules are rare fungal virulence factors that are critical for protecting C. neoformans from phagocytosis by macrophages. To date, more than 75 proteins involved in capsule synthesis and cell wall attachment have been reported in C. neoformans; however, their complex upstream signaling networks remain elusive. In this study, we demonstrated that Ada2, Yap1, Bzp4, and Gat201 were key capsule-inducing transcriptional regulators. Yap1 and Ada2 function upstream of Gat201, whereas Bzp4 and Gat201 function independently. Genome-wide transcriptome profiling revealed that Bzp4, Gat201, and Ada2 promote capsule production and attachment by positively and negatively regulating genes involved in capsule synthesis and chitin/chitosan synthesis, respectively. Thus, this study provides comprehensive insights into the complex capsule-regulating signaling pathway in C. neoformans.
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Affiliation(s)
- Eun-Ha Jang
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Ji-Seok Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Seong-Ryong Yu
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
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Extension of O-Linked Mannosylation in the Golgi Apparatus Is Critical for Cell Wall Integrity Signaling and Interaction with Host Cells in Cryptococcus neoformans Pathogenesis. mBio 2022; 13:e0211222. [PMID: 36409123 PMCID: PMC9765558 DOI: 10.1128/mbio.02112-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The human-pathogenic yeast Cryptococcus neoformans assembles two types of O-linked glycans on its proteins. In this study, we identified and functionally characterized the C. neoformans CAP6 gene, encoding an α1,3-mannosyltransferase responsible for the second mannose addition to minor O-glycans containing xylose in the Golgi apparatus. Two cell surface sensor proteins, Wml1 (WSC/Mid2-like) and Wml2, were found to be independent substrates of Cap6-mediated minor or Ktr3-mediated major O-mannosylation, respectively. The double deletion of KTR3 and CAP6 (ktr3Δ cap6Δ) completely blocked the mannose addition at the second position of O-glycans, resulting in the accumulation of proteins with O-glycans carrying only a single mannose. Tunicamycin (TM)-induced phosphorylation of the Mpk1 mitogen-activated protein kinase (MAPK) was greatly decreased in both ktr3Δ cap6Δ and wml1Δ wml2Δ strains. Transcriptome profiling of the ktr3Δ cap6Δ strain upon TM treatment revealed decreased expression of genes involved in the Mpk1-dependent cell wall integrity (CWI) pathway. Consistent with its defective growth under several stress conditions, the ktr3Δ cap6Δ strain was avirulent in a mouse model of cryptococcosis. Associated with this virulence defect, the ktr3Δ cap6Δ strain showed decreased adhesion to lung epithelial cells, decreased proliferation within macrophages, and reduced transcytosis of the blood-brain barrier (BBB). Notably, the ktr3Δ cap6Δ strain showed reduced induction of the host immune response and defective trafficking of ergosterol, an immunoreactive fungal molecule. In conclusion, O-glycan extension in the Golgi apparatus plays critical roles in various pathobiological processes, such as CWI signaling and stress resistance and interaction with host cells in C. neoformans. IMPORTANCE Cryptococcus neoformans assembles two types of O-linked glycans on its surface proteins, the more abundant major O-glycans that do not contain xylose residues and minor O-glycans containing xylose. Here, we demonstrate the role of the Cap6 α1,3-mannosyltransferase in the synthesis of minor O-glycans. Previously proposed to be involved in capsule biosynthesis, Cap6 works with the related Ktr3 α1,2-mannosyltransferase to synthesize O-glycans on their target proteins. We also identified two novel C. neoformans stress sensors that require Ktr3- and Cap6-mediated posttranslational modification for full function. Accordingly, the ktr3Δ cap6Δ double O-glycan mutant strain displays defects in stress signaling pathways, CWI, and ergosterol trafficking. Furthermore, the ktr3Δ cap6Δ strain is completely avirulent in a mouse infection model. Together, these results demonstrate critical roles for O-glycosylation in fungal pathogenesis. As there are no human homologs for Cap6 or Ktr3, these fungus-specific mannosyltransferases are novel targets for antifungal therapy.
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Abstract
The KEOPS (kinase, putative endopeptidase, and other proteins of small size) complex has critical functions in eukaryotes; however, its role in fungal pathogens remains elusive. Herein, we comprehensively analyzed the pathobiological functions of the fungal KEOPS complex in Cryptococcus neoformans (Cn), which causes fatal meningoencephalitis in humans. We identified four CnKEOPS components: Pcc1, Kae1, Bud32, and Cgi121. Deletion of PCC1, KAE1, or BUD32 caused severe defects in vegetative growth, cell cycle control, sexual development, general stress responses, and virulence factor production, whereas deletion of CGI121 led to similar but less severe defects. This suggests that Pcc1, Kae1, and Bud32 are the core KEOPS components, and Cgi121 may play auxiliary roles. Nevertheless, all KEOPS components were essential for C. neoformans pathogenicity. Although the CnKEOPS complex appeared to have a conserved linear arrangement of Pcc1-Kae1-Bud32-Cgi121, as supported by physical interaction between Pcc1-Kae1 and Kae1-Bud32, CnBud32 was found to have a unique extended loop region that was critical for the KEOPS functions. Interestingly, CnBud32 exhibited both kinase activity-dependent and -independent functions. Supporting its pleiotropic roles, the CnKEOPS complex not only played conserved roles in t6A modification of ANN codon-recognizing tRNAs but also acted as a major transcriptional regulator, thus controlling hundreds of genes involved in various cellular processes, particularly ergosterol biosynthesis. In conclusion, the KEOPS complex plays both evolutionarily conserved and divergent roles in controlling the pathobiological features of C. neoformans and could be an anticryptococcal drug target. IMPORTANCE The cellular function and structural configuration of the KEOPS complex have been elucidated in some eukaryotes and archaea but have never been fully characterized in fungal pathogens. Here, we comprehensively analyzed the pathobiological roles of the KEOPS complex in the globally prevalent fungal meningitis-causing pathogen C. neoformans. The CnKEOPS complex, composed of a linear arrangement of Pcc1-Kae1-Bud32-Cgi121, not only played evolutionarily conserved roles in growth, sexual development, stress responses, and tRNA modification but also had unique roles in controlling virulence factor production and pathogenicity. Notably, a unique extended loop structure in CnBud32 is critical for the KEOPS complex in C. neoformans. Supporting its pleiotropic roles, transcriptome analysis revealed that the CnKEOPS complex governs several hundreds of genes involved in carbon and amino acid metabolism, pheromone response, and ergosterol biosynthesis. Therefore, this study provides novel insights into the fungal KEOPS complex that could be exploited as a potential antifungal drug target.
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Choi Y, Lee HH, Park J, Kim S, Choi S, Moon H, Shin J, Kim JE, Choi GJ, Seo YS, Son H. Intron turnover is essential to the development and pathogenicity of the plant pathogenic fungus Fusarium graminearum. Commun Biol 2022; 5:1129. [PMID: 36289323 PMCID: PMC9606315 DOI: 10.1038/s42003-022-04111-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 10/14/2022] [Indexed: 11/09/2022] Open
Abstract
Intron lariats excised during the splicing process are rapidly degraded by RNA lariat debranching enzyme (Dbr1) and several exonucleases. Rapid turnover of lariat RNA is essential to cellular RNA homeostasis. However, the functions of Dbr1 have not been investigated in filamentous fungi. Here, we characterized the molecular functions of Dbr1 in Fusarium graminearum, a major fungal plant pathogen. Deletion of FgDBR1 resulted in pleiotropic defects in hyphal growth, conidiation, sexual reproduction, and virulence. Through transcriptome analysis, we revealed that the deletion mutant exhibited global accumulation of intron lariats and upregulation of ribosome-related genes. Excessive accumulation of lariat RNA led to reduced overall protein synthesis, causing various phenotypic defects in the absence of FgDBR1. The results of this study demonstrate that a compromised intron turnover process affects development and pathogenesis in this fungus and that Dbr1 function is critical to plant pathogenic fungi. RNA lariat debranching enzyme Dbr1 is required for intron turnover in the fungal plant pathogen <i>Fusarium graminearum <i > , and accumulation of lariat RNA affects its development and pathogenesis.
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Affiliation(s)
- Yejin Choi
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Hyun-Hee Lee
- grid.262229.f0000 0001 0719 8572Department of Integrated Biological Science, Pusan National University, Busan, 46247 Republic of Korea
| | - Jiyeun Park
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Sieun Kim
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Soyoung Choi
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Heeji Moon
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Jiyoung Shin
- grid.31501.360000 0004 0470 5905Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
| | - Jung-Eun Kim
- grid.31501.360000 0004 0470 5905Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
| | - Gyung Ja Choi
- grid.29869.3c0000 0001 2296 8192Therapeutic & Biotechnology Division, Center for Eco-friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, 34114 Republic of Korea
| | - Young-Su Seo
- grid.262229.f0000 0001 0719 8572Department of Integrated Biological Science, Pusan National University, Busan, 46247 Republic of Korea
| | - Hokyoung Son
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea ,grid.31501.360000 0004 0470 5905Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
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16
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Ianiri G, LeibundGut-Landmann S, Dawson TL. Malassezia: A Commensal, Pathogen, and Mutualist of Human and Animal Skin. Annu Rev Microbiol 2022; 76:757-782. [PMID: 36075093 DOI: 10.1146/annurev-micro-040820-010114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Identified in the late nineteenth century as a single species residing on human skin, Malassezia is now recognized as a diverse genus comprising 18 species inhabiting not only skin but human gut, hospital environments, and even deep-sea sponges. All cultivated Malassezia species are lipid dependent, having lost genes for lipid synthesis and carbohydrate metabolism. The surging interest in Malassezia results from development of tools to improve sampling, culture, identification, and genetic engineering, which has led to findings implicating it in numerous skin diseases, Crohn disease, and pancreatic cancer. However, it has become clear that Malassezia plays a multifaceted role in human health, with mutualistic activity in atopic dermatitis and a preventive effect against other skin infections due to its potential to compete with skin pathogens such as Candida auris. Improved understanding of complex microbe-microbe and host-microbe interactions will be required to define Malassezia's role in human and animal health and disease so as to design targeted interventions.
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Affiliation(s)
- Giuseppe Ianiri
- Department of Agricultural, Environmental, and Food Sciences, University of Molise, Campobasso, Italy
| | - Salomé LeibundGut-Landmann
- Section of Immunology, Faculty of Vetsuisse, and Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Thomas L Dawson
- Skin Research Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore; .,Department of Drug Discovery, College of Pharmacy, Medical University of South Carolina, Charleston, South Carolina, USA
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17
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Nicoletti G, White K. The Anti-Fungal Activity of Nitropropenyl Benzodioxole (NPBD), a Redox-Thiol Oxidant and Tyrosine Phosphatase Inhibitor. Antibiotics (Basel) 2022; 11:antibiotics11091188. [PMID: 36139967 PMCID: PMC9495065 DOI: 10.3390/antibiotics11091188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/28/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022] Open
Abstract
Phylogenetically diverse fungal species are an increasing cause of severe disease and mortality. Identification of new targets and development of new fungicidal drugs are required to augment the effectiveness of current chemotherapy and counter increasing resistance in pathogens. Nitroalkenyl benzene derivatives are thiol oxidants and inhibitors of cysteine-based molecules, which show broad biological activity against microorganisms. Nitropropenyl benzodioxole (NPBD), one of the most active antimicrobial derivatives, shows high activity in MIC assays for phylogenetically diverse saprophytic, commensal and parasitic fungi. NPBD was fungicidal to all species except the dermatophytic fungi, with an activity profile comparable to that of Amphotericin B and Miconazole. NPBD showed differing patterns of dynamic kill rates under different growth conditions for Candida albicans and Aspergillus fumigatus and was rapidly fungicidal for non-replicating vegetative forms and microconidia. It did not induce resistant or drug tolerant strains in major pathogens on long term exposure. A literature review highlights the complexity and interactivity of fungal tyrosine phosphate and redox signaling pathways, their differing metabolic effects in fungal species and identifies some targets for inhibition. A comparison of the metabolic activities of Amphotericin B, Miconazole and NPBD highlights the multiple cellular functions of these agents and the complementarity of many mechanisms. The activity profile of NPBD illustrates the functional diversity of fungal tyrosine phosphatases and thiol-based redox active molecules and contributes to the validation of tyrosine phosphatases and redox thiol molecules as related and complementary selective targets for antimicrobial drug development. NPBD is a selective antifungal agent with low oral toxicity which would be suitable for local treatment of skin and mucosal infections.
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18
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Gervais NC, Halder V, Shapiro RS. A data library of Candida albicans functional genomic screens. FEMS Yeast Res 2021; 21:6433625. [PMID: 34864983 DOI: 10.1093/femsyr/foab060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/19/2021] [Indexed: 12/12/2022] Open
Abstract
Functional genomic screening of genetic mutant libraries enables the characterization of gene function in diverse organisms. For the fungal pathogen Candida albicans, several genetic mutant libraries have been generated and screened for diverse phenotypes, including tolerance to environmental stressors and antifungal drugs, and pathogenic traits such as cellular morphogenesis, biofilm formation and host-pathogen interactions. Here, we compile and organize C. albicans functional genomic screening data from ∼400 screens, to generate a data library of genetic mutant strains analyzed under diverse conditions. For quantitative screening data, we normalized these results to enable quantitative and comparative analysis of different genes across different phenotypes. Together, this provides a unique C. albicans genetic database, summarizing abundant phenotypic data from functional genomic screens in this critical fungal pathogen.
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Affiliation(s)
- Nicholas C Gervais
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Viola Halder
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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19
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Crunden JL, Diezmann S. Hsp90 interaction networks in fungi-tools and techniques. FEMS Yeast Res 2021; 21:6413543. [PMID: 34718512 PMCID: PMC8599792 DOI: 10.1093/femsyr/foab054] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 10/26/2021] [Indexed: 01/01/2023] Open
Abstract
Heat-shock protein 90 (Hsp90) is a central regulator of cellular proteostasis. It stabilizes numerous proteins that are involved in fundamental processes of life, including cell growth, cell-cycle progression and the environmental response. In addition to stabilizing proteins, Hsp90 governs gene expression and controls the release of cryptic genetic variation. Given its central role in evolution and development, it is important to identify proteins and genes that interact with Hsp90. This requires sophisticated genetic and biochemical tools, including extensive mutant collections, suitable epitope tags, proteomics approaches and Hsp90-specific pharmacological inhibitors for chemogenomic screens. These usually only exist in model organisms, such as the yeast Saccharomyces cerevisiae. Yet, the importance of other fungal species, such as Candida albicans and Cryptococcus neoformans, as serious human pathogens accelerated the development of genetic tools to study their virulence and stress response pathways. These tools can also be exploited to map Hsp90 interaction networks. Here, we review tools and techniques for Hsp90 network mapping available in different fungi and provide a summary of existing mapping efforts. Mapping Hsp90 networks in fungal species spanning >500 million years of evolution provides a unique vantage point, allowing tracking of the evolutionary history of eukaryotic Hsp90 networks.
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Affiliation(s)
- Julia L Crunden
- School of Cellular and Molecular Medicine, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Stephanie Diezmann
- School of Cellular and Molecular Medicine, University of Bristol, University Walk, Bristol BS8 1TD, UK
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20
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Shi H, Meng S, Qiu J, Wang C, Shu Y, Luo C, Kou Y. MoWhi2 regulates appressorium formation and pathogenicity via the MoTor signalling pathway in Magnaporthe oryzae. MOLECULAR PLANT PATHOLOGY 2021; 22:969-983. [PMID: 34036714 PMCID: PMC8295519 DOI: 10.1111/mpp.13074] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/13/2021] [Accepted: 04/21/2021] [Indexed: 05/17/2023]
Abstract
Magnaporthe oryzae causes rice blast disease, which seriously threatens the safety of food production. Understanding the mechanism of appressorium formation, which is one of the key steps for successful infection by M. oryzae, is helpful to formulate effective control strategies of rice blast. In this study, we identified MoWhi2, the homolog of Saccharomyces cerevisiae Whi2 (Whisky2), as an important regulator that controls appressorium formation in M. oryzae. When MoWHI2 was disrupted, multiple appressoria were formed by one conidium and pathogenicity was significantly reduced. A putative phosphatase, MoPsr1, was identified to interact with MoWhi2 using a yeast two-hybridization screening assay. The knockout mutant ΔMopsr1 displayed similar phenotypes to the ΔMowhi2 strain. Both the ΔMowhi2 and ΔMopsr1 mutants could form appressoria on a hydrophilic surface with cAMP levels increasing in comparison with the wild type (WT). The conidia of ΔMowhi2 and ΔMopsr1 formed a single appressorium per conidium, similar to WT, when the target of rapamycin (TOR) inhibitor rapamycin was present. In addition, compared with WT, the expression levels of MoTOR and the MoTor signalling activation marker gene MoRS3 were increased, suggesting that inappropriate activation of the MoTor signalling pathway is one of the important reasons for the defects in appressorium formation in the ΔMowhi2 and ΔMopsr1 strains. Our results provide insights into MoWhi2 and MoPsr1-mediated appressorium development and pathogenicity by regulating cAMP levels and the activation of MoTor signalling in M. oryzae.
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Affiliation(s)
- Huanbin Shi
- State Key Laboratory of Rice BiologyChina National Rice Research InstituteHangzhouChina
| | - Shuai Meng
- State Key Laboratory of Rice BiologyChina National Rice Research InstituteHangzhouChina
- Hubei Key Lab of Plant Pathology, and College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhanChina
| | - Jiehua Qiu
- State Key Laboratory of Rice BiologyChina National Rice Research InstituteHangzhouChina
| | - Congcong Wang
- State Key Laboratory of Rice BiologyChina National Rice Research InstituteHangzhouChina
| | - Yazhou Shu
- State Key Laboratory of Rice BiologyChina National Rice Research InstituteHangzhouChina
| | - Chaoxi Luo
- Hubei Key Lab of Plant Pathology, and College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhanChina
| | - Yanjun Kou
- State Key Laboratory of Rice BiologyChina National Rice Research InstituteHangzhouChina
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21
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Jin JH, Choi MK, Cho HS, Bahn YS. Zinc-binding domain mediates pleiotropic functions of Yvh1 in Cryptococcus neoformans. J Microbiol 2021; 59:658-665. [PMID: 34212289 DOI: 10.1007/s12275-021-1287-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/03/2021] [Accepted: 06/03/2021] [Indexed: 11/28/2022]
Abstract
Yvh1 is a dual-specificity phosphatase (DUSP) that is evolutionarily conserved in eukaryotes, including yeasts and humans. Yvh1 is involved in the vegetative growth, differentiation, and virulence of animal and plant fungal pathogens. All Yvh1 orthologs have a conserved DUSP catalytic domain at the N-terminus and a zinc-binding (ZB) domain with two zinc fingers (ZFs) at the C-terminus. Although the DUSP domain is implicated in the regulation of MAPK signaling in humans, only the ZB domain is essential for most cellular functions of Yvh1 in fungi. This study aimed to analyze the functions of the DUSP and ZB domains of Yvh1 in the human fungal pathogen Cryptococcus neoformans, whose Yvh1 (CnYvh1) contains a DUSP domain at the C-terminus and a ZB domain at the N-terminus. Notably, CnYvh1 has an extended internal domain between the two ZF motifs in the ZB domain. To elucidate the function of each domain, we constructed individual domain deletions and swapping strains by complementing the yvh1Δ mutant with wild-type (WT) or mutated YVH1 alleles and examined their Yvh1-dependent phenotypes, including growth under varying stress conditions, mating, and virulence factor production. Here, we found that the complementation of the yvh1Δ mutant with the mutated YVH1 alleles having two ZFs of the ZB domain, but not the DUSP and extended internal domains, restored the WT phenotypic traits in the yvh1Δ mutant. In conclusion, the ZB domain, but not the N-terminal DUSP domain, plays a pivotal role in the pathobiological functions of cryptococcal Yvh1.
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Affiliation(s)
- Jae-Hyung Jin
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Myung Kyung Choi
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Hyun-Soo Cho
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea.
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22
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Mattoon ER, Casadevall A, Cordero RJB. Beat the heat: correlates, compounds, and mechanisms involved in fungal thermotolerance. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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23
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Nguyen S, Truong JQ, Bruning JB. Targeting Unconventional Pathways in Pursuit of Novel Antifungals. Front Mol Biosci 2021; 7:621366. [PMID: 33511160 PMCID: PMC7835888 DOI: 10.3389/fmolb.2020.621366] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 12/11/2020] [Indexed: 01/31/2023] Open
Abstract
The impact of invasive fungal infections on human health is a serious, but largely overlooked, public health issue. Commonly affecting the immunocompromised community, fungal infections are predominantly caused by species of Candida, Cryptococcus, and Aspergillus. Treatments are reliant on the aggressive use of pre-existing antifungal drug classes that target the fungal cell wall and membrane. Despite their frequent use, these drugs are subject to unfavorable drug-drug interactions, can cause undesirable side-effects and have compromised efficacy due to the emergence of antifungal resistance. Hence, there is a clear need to develop novel classes of antifungal drugs. A promising approach involves exploiting the metabolic needs of fungi by targeted interruption of essential metabolic pathways. This review highlights potential antifungal targets including enolase, a component of the enolase-plasminogen complex, and enzymes from the mannitol biosynthesis and purine nucleotide biosynthesis pathways. There has been increased interest in the enzymes that comprise these particular pathways and further investigation into their merits as antifungal targets and roles in fungal survival and virulence are warranted. Disruption of these vital processes by targeting unconventional pathways with small molecules or antibodies may serve as a promising approach to discovering novel classes of antifungals.
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Affiliation(s)
- Stephanie Nguyen
- Institute of Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Jia Q Truong
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - John B Bruning
- Institute of Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
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24
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Jung KW, Lee KT, Bahn YS. A Signature-Tagged Mutagenesis (STM)-based murine-infectivity assay for Cryptococcus neoformans. J Microbiol 2020; 58:823-831. [PMID: 32989639 DOI: 10.1007/s12275-020-0341-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/12/2020] [Indexed: 11/26/2022]
Abstract
Signature-tagged mutagenesis (STM) is a high-throughput genetic technique that can be used to investigate the function of genes by constructing a large number of mutant strains with unique DNA identification tags, pooling them, and screening them for a particular phenotypic trait. STM was first designed for the identification of genes that contribute to the virulence or infectivity of a pathogen in its host. Recently, this method has also been applied for the identification of mutants with specific phenotypes, such as antifungal drug resistance and proliferation. In the present study, we describe an STM method for the identification of genes contributing to the infectivity of Cryptococcus neoformans using a mutant library, in which each strain was tagged with a unique DNA sequence.
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Affiliation(s)
- Kwang-Woo Jung
- Radiation Research Division, Korea Atomic Energy Research Institute, Jeongeup o56212, Republic of Korea
| | - Kyung-Tae Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea.
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