1
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Kawamukai M. Regulation of sexual differentiation initiation in Schizosaccharomyces pombe. Biosci Biotechnol Biochem 2024; 88:475-492. [PMID: 38449372 DOI: 10.1093/bbb/zbae019] [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: 01/16/2024] [Accepted: 02/05/2024] [Indexed: 03/08/2024]
Abstract
The fission yeast Schizosaccharomyces pombe is an excellent model organism to explore cellular events owing to rich tools in genetics, molecular biology, cellular biology, and biochemistry. Schizosaccharomyces pombe proliferates continuously when nutrients are abundant but arrests in G1 phase upon depletion of nutrients such as nitrogen and glucose. When cells of opposite mating types are present, cells conjugate, fuse, undergo meiosis, and finally form 4 spores. This sexual differentiation process in S. pombe has been studied extensively. To execute sexual differentiation, the glucose-sensing cAMP-PKA (cyclic adenosine monophosphate-protein kinase A) pathway, nitrogen-sensing TOR (target of rapamycin) pathway, and SAPK (stress-activating protein kinase) pathway are crucial, and the MAPK (mitogen-activating protein kinase) cascade is essential for pheromone sensing. These signals regulate ste11 at the transcriptional and translational levels, and Ste11 is modified in multiple ways. This review summarizes the initiation of sexual differentiation in S. pombe based on results I have helped to obtain, including the work of many excellent researchers.
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Affiliation(s)
- Makoto Kawamukai
- D epartment of Life Sciences, Faculty of Life and Environmental Sciences, Shimane University, Nishikawatsu, Matsue, Japan
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2
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Marešová A, Oravcová M, Rodríguez-López M, Hradilová M, Zemlianski V, Häsler R, Hernández P, Bähler J, Převorovský M. Critical importance of DNA binding for CSL protein functions in fission yeast. J Cell Sci 2024; 137:jcs261568. [PMID: 38482739 DOI: 10.1242/jcs.261568] [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: 08/22/2023] [Accepted: 03/07/2024] [Indexed: 05/01/2024] Open
Abstract
CSL proteins [named after the homologs CBF1 (RBP-Jκ in mice), Suppressor of Hairless and LAG-1] are conserved transcription factors found in animals and fungi. In the fission yeast Schizosaccharomyces pombe, they regulate various cellular processes, including cell cycle progression, lipid metabolism and cell adhesion. CSL proteins bind to DNA through their N-terminal Rel-like domain and central β-trefoil domain. Here, we investigated the importance of DNA binding for CSL protein functions in fission yeast. We created CSL protein mutants with disrupted DNA binding and found that the vast majority of CSL protein functions depend on intact DNA binding. Specifically, DNA binding is crucial for the regulation of cell adhesion, lipid metabolism, cell cycle progression, long non-coding RNA expression and genome integrity maintenance. Interestingly, perturbed lipid metabolism leads to chromatin structure changes, potentially linking lipid metabolism to the diverse phenotypes associated with CSL protein functions. Our study highlights the critical role of DNA binding for CSL protein functions in fission yeast.
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Affiliation(s)
- Anna Marešová
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Martina Oravcová
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - María Rodríguez-López
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Miluše Hradilová
- Laboratory of Genomics and Bioinformatics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czechia
| | - Viacheslav Zemlianski
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Robert Häsler
- Center for Inflammatory Skin Diseases, Department of Dermatology and Allergy, University Hospital Schleswig-Holstein, Campus Kiel, Rosalind-Franklin-Straße 9, 24105 Kiel, Germany
| | - Pablo Hernández
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Jürg Bähler
- Institute of Healthy Ageing and Department of Genetics, Evolution and Environment , University College London, Gower Street, London WC1E 6BT, UK
| | - Martin Převorovský
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
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3
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Ohtsuka H, Sakata H, Kitazaki Y, Tada M, Shimasaki T, Otsubo Y, Maekawa Y, Kobayashi M, Imada K, Yamashita A, Aiba H. The ecl family gene ecl3+ is induced by phosphate starvation and contributes to sexual differentiation in fission yeast. J Cell Sci 2023; 136:287015. [PMID: 36779416 PMCID: PMC10038150 DOI: 10.1242/jcs.260759] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 02/07/2023] [Indexed: 02/14/2023] Open
Abstract
In Schizosaccharomyces pombe, ecl family genes are induced by several signals, such as starvation of various nutrients, including sulfur, amino acids and Mg2+, and environmental stress, including heat or oxidative stress. These genes mediate appropriate cellular responses and contribute to the maintenance of cell viability and induction of sexual differentiation. Although this yeast has three ecl family genes with overlapping functions, any environmental conditions that induce ecl3+ remain unidentified. We demonstrate that ecl3+ is induced by phosphate starvation, similar to its chromosomally neighboring genes, pho1+ and pho84+, which respectively encode an extracellular acid phosphatase and an inorganic phosphate transporter. ecl3+ expression was induced by the transcription factor Pho7 and affected by the cyclin-dependent kinase (CDK)-activating kinase Csk1. Phosphate starvation induced G1 arrest and sexual differentiation via ecl family genes. Biochemical analyses suggested that this G1 arrest was mediated by the stabilization of the CDK inhibitor Rum1, which was dependent on ecl family genes. This study shows that ecl family genes are required for appropriate responses to phosphate starvation and provides novel insights into the diversity and similarity of starvation responses.
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Affiliation(s)
- Hokuto Ohtsuka
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Hiroki Sakata
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Yuto Kitazaki
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Masanobu Tada
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Takafumi Shimasaki
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Yoko Otsubo
- Interdisciplinary Research Unit, National Institute for Basic Biology, Okazaki, Aichi 444-858, Japan
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
- Center for Novel Science Initiatives, National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan
| | - Yasukichi Maekawa
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Mikuto Kobayashi
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Kazuki Imada
- Department of Chemistry and Biochemistry, National Institute of Technology (KOSEN), Suzuka College, Suzuka 510-0294, Japan
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Akira Yamashita
- Interdisciplinary Research Unit, National Institute for Basic Biology, Okazaki, Aichi 444-858, Japan
- Center for Low-temperature Plasma Sciences, Nagoya University, Nagoya, Aichi 464-8603, Japan
| | - Hirofumi Aiba
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
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4
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Hicks SN, Venters RA, Blackshear PJ. Backbone and sidechain 1H, 15N and 13C resonance assignments of the free and RNA-bound tandem zinc finger domain of the tristetraprolin family member from Selaginella moellendorffii. BIOMOLECULAR NMR ASSIGNMENTS 2022; 16:153-158. [PMID: 35279790 PMCID: PMC9196822 DOI: 10.1007/s12104-022-10073-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
Members of the tristetraprolin (TTP) family of RNA binding proteins (RBPs) regulate the metabolism of a variety of mRNA targets. In mammals, these proteins modulate many physiological processes, including immune cell activation, hematopoiesis, and embryonic development. Regulation of mRNA stability by these proteins requires that the tandem zinc finger (TZF) domain binds initially and directly to target mRNAs, ultimately leading to their deadenylation and decay. Proteins of this type throughout eukarya possess a highly conserved TZF domain, suggesting that they are all capable of high-affinity RNA binding. However, the mechanism of TTP-mediated mRNA decay is largely undefined. Given the vital role that these TTP family proteins play in maintaining RNA homeostasis throughout eukaryotes, we focused here on the first, key step in this process: recognition and binding of the TZF domain to target RNA. For these studies, we chose a primitive plant, the spikemoss Selaginella moellendorffii, which last shared a common ancestor with humans more than a billion years ago. Here we report the near complete backbone and side chain resonance assignments of the spikemoss TZF domain, including: (1) the assignment of the RNA-TZF domain complex, representing one of only two data sets currently available for the entire TTP family of proteins; and (2) the first NMR resonance assignments of the entire TZF domain, in the RNA-free form. This work will serve as the basis for further NMR structural investigations aimed at gaining insights into the process of RNA recognition and the mechanisms of TTP-mediated mRNA decay.
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Affiliation(s)
- Stephanie N Hicks
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA.
| | - Ronald A Venters
- Duke University NMR Center, Duke University, Durham, NC, 27710, USA
- Department of Radiology, Duke University, Durham, NC, 27710, USA
| | - Perry J Blackshear
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Biochemistry, Duke University Medical Center, Durham, NC, 27710, USA
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5
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Bai W, Wells ML, Lai WS, Hicks SN, Burkholder AB, Perera L, Kimmel AR, Blackshear PJ. A post-transcriptional regulon controlled by TtpA, the single tristetraprolin family member expressed in Dictyostelium discoideum. Nucleic Acids Res 2021; 49:11920-11937. [PMID: 34718768 DOI: 10.1093/nar/gkab983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 10/05/2021] [Accepted: 10/12/2021] [Indexed: 12/30/2022] Open
Abstract
Post-transcriptional processes mediated by mRNA binding proteins represent important control points in gene expression. In eukaryotes, mRNAs containing specific AU-rich motifs are regulated by binding of tristetraprolin (TTP) family tandem zinc finger proteins, which promote mRNA deadenylation and decay, partly through interaction of a conserved C-terminal CNOT1 binding (CNB) domain with CCR4-NOT protein complexes. The social ameba Dictyostelium discoideum shared a common ancestor with humans more than a billion years ago, and expresses only one TTP family protein, TtpA, in contrast to three members expressed in humans. Evaluation of ttpA null-mutants identified six transcripts that were consistently upregulated compared to WT during growth and early development. The 3'-untranslated regions (3'-UTRs) of all six 'TtpA-target' mRNAs contained multiple TTP binding motifs (UUAUUUAUU), and one 3'-UTR conferred TtpA post-transcriptional stability regulation to a heterologous mRNA that was abrogated by mutations in the core TTP-binding motifs. All six target transcripts were upregulated to similar extents in a C-terminal truncation mutant, in contrast to less severe effects of analogous mutants in mice. All six target transcripts encoded probable membrane proteins. In Dictyostelium, TtpA may control an 'RNA regulon', where a single RNA binding protein, TtpA, post-transcriptionally co-regulates expression of several functionally related proteins.
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Affiliation(s)
- Wenli Bai
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Melissa L Wells
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Wi S Lai
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Stephanie N Hicks
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Adam B Burkholder
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Alan R Kimmel
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Perry J Blackshear
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.,The Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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6
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Rana A, Gupta N, Thakur A. Post-transcriptional and translational control of the morphology and virulence in human fungal pathogens. Mol Aspects Med 2021; 81:101017. [PMID: 34497025 DOI: 10.1016/j.mam.2021.101017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 08/13/2021] [Accepted: 08/20/2021] [Indexed: 11/17/2022]
Abstract
Host-pathogen interactions at the molecular level are the key to fungal pathogenesis. Fungal pathogens utilize several mechanisms such as adhesion, invasion, phenotype switching and metabolic adaptations, to survive in the host environment and respond. Post-transcriptional and translational regulations have emerged as key regulatory mechanisms ensuring the virulence and survival of fungal pathogens. Through these regulations, fungal pathogens effectively alter their protein pool, respond to various stress, and undergo morphogenesis, leading to efficient and comprehensive changes in fungal physiology. The regulation of virulence through post-transcriptional and translational regulatory mechanisms is mediated through mRNA elements (cis factors) or effector molecules (trans factors). The untranslated regions upstream and downstream of the mRNA, as well as various RNA-binding proteins involved in translation initiation or circularization of the mRNA, play pivotal roles in the regulation of morphology and virulence by influencing protein synthesis, protein isoforms, and mRNA stability. Therefore, post-transcriptional and translational mechanisms regulating the morphology, virulence and drug-resistance processes in fungal pathogens can be the target for new therapeutics. With improved "omics" technologies, these regulatory mechanisms are increasingly coming to the forefront of basic biology and drug discovery. This review aims to discuss various modes of post-transcriptional and translation regulations, and how these mechanisms exert influence in the virulence and morphogenesis of fungal pathogens.
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Affiliation(s)
- Aishwarya Rana
- Regional Centre for Biotechnology, 3rd Milestone Gurgaon-Faridabad Expressway, Faridabad 121001, India
| | - Nidhi Gupta
- Regional Centre for Biotechnology, 3rd Milestone Gurgaon-Faridabad Expressway, Faridabad 121001, India
| | - Anil Thakur
- Regional Centre for Biotechnology, 3rd Milestone Gurgaon-Faridabad Expressway, Faridabad 121001, India.
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7
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Busada JT, Khadka S, Peterson KN, Druffner SR, Stumpo DJ, Zhou L, Oakley RH, Cidlowski JA, Blackshear PJ. Tristetraprolin Prevents Gastric Metaplasia in Mice by Suppressing Pathogenic Inflammation. Cell Mol Gastroenterol Hepatol 2021; 12:1831-1845. [PMID: 34358715 PMCID: PMC8554534 DOI: 10.1016/j.jcmgh.2021.07.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 07/27/2021] [Accepted: 07/27/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Aberrant immune activation is associated with numerous inflammatory and autoimmune diseases and contributes to cancer development and progression. Within the stomach, inflammation drives a well-established sequence from gastritis to metaplasia, eventually resulting in adenocarcinoma. Unfortunately, the processes that regulate gastric inflammation and prevent carcinogenesis remain unknown. Tristetraprolin (TTP) is an RNA-binding protein that promotes the turnover of numerous proinflammatory and oncogenic messenger RNAs. Here, we assess the role of TTP in regulating gastric inflammation and spasmolytic polypeptide-expressing metaplasia (SPEM) development. METHODS We used a TTP-overexpressing model, the TTPΔadenylate-uridylate rich element mouse, to examine whether TTP can protect the stomach from adrenalectomy (ADX)-induced gastric inflammation and SPEM. RESULTS We found that TTPΔadenylate-uridylate rich element mice were completely protected from ADX-induced gastric inflammation and SPEM. RNA sequencing 5 days after ADX showed that TTP overexpression suppressed the expression of genes associated with the innate immune response. Importantly, TTP overexpression did not protect from high-dose-tamoxifen-induced SPEM development, suggesting that protection in the ADX model is achieved primarily by suppressing inflammation. Finally, we show that protection from gastric inflammation was only partially due to the suppression of Tnf, a well-known TTP target. CONCLUSIONS Our results show that TTP exerts broad anti-inflammatory effects in the stomach and suggest that therapies that increase TTP expression may be effective treatments of proneoplastic gastric inflammation. Transcript profiling: GSE164349.
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Affiliation(s)
- Jonathan T. Busada
- Molecular Endocrinology Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina,Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia,Correspondence Address correspondence to: Jonathan T. Busada, PhD, Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, 64 Medical Center Drive, PO Box 9177, Morgantown, West Virginia 26506.
| | - Stuti Khadka
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Kylie N. Peterson
- Molecular Endocrinology Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Sara R. Druffner
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Deborah J. Stumpo
- Post-Transcriptional Gene Expression Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Lecong Zhou
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Robert H. Oakley
- Molecular Endocrinology Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - John A. Cidlowski
- Molecular Endocrinology Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Perry J. Blackshear
- Post-Transcriptional Gene Expression Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
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8
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Martínez-Pastor MT, Puig S. Adaptation to iron deficiency in human pathogenic fungi. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118797. [PMID: 32663505 DOI: 10.1016/j.bbamcr.2020.118797] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/13/2020] [Accepted: 07/05/2020] [Indexed: 02/08/2023]
Abstract
Iron is an essential micronutrient for virtually all eukaryotic organisms and plays a central role during microbial infections. Invasive fungal diseases are associated with strikingly high rates of mortality, but their impact on human health is usually underestimated. Upon a fungal infection, hosts restrict iron availability in order to limit the growth and virulence of the pathogen. Here, we use two model yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, to delve into the response to iron deficiency of human fungal pathogens, such as Candida glabrata, Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans. Fungi possess common and species-specific mechanisms to acquire iron and to control the response to iron limitation. Upon iron scarcity, fungi activate a wide range of elegant strategies to capture and import exogenous iron, mobilize iron from intracellular stores, and modulate their metabolism to economize and prioritize iron utilization. Hence, iron homeostasis genes represent remarkable virulence factors that can be used as targets for the development of novel antifungal treatments.
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Affiliation(s)
| | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain.
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9
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Lai WS, Stumpo DJ, Wells ML, Gruzdev A, Hicks SN, Nicholson CO, Yang Z, Faccio R, Webster MW, Passmore LA, Blackshear PJ. Importance of the Conserved Carboxyl-Terminal CNOT1 Binding Domain to Tristetraprolin Activity In Vivo. Mol Cell Biol 2019; 39:e00029-19. [PMID: 31036567 PMCID: PMC6580703 DOI: 10.1128/mcb.00029-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/12/2019] [Accepted: 04/19/2019] [Indexed: 01/19/2023] Open
Abstract
Tristetraprolin (TTP) is an anti-inflammatory protein that modulates the stability of certain cytokine/chemokine mRNAs. After initial high-affinity binding to AU-rich elements in 3' untranslated regions of target mRNAs, mediated through its tandem zinc finger (TZF) domain, TTP promotes the deadenylation and ultimate decay of target transcripts. These transcripts and their encoded proteins accumulate abnormally in TTP knockout (KO) mice, leading to a severe inflammatory syndrome. To assess the importance of the highly conserved C-terminal CNOT1 binding domain (CNBD) of TTP to the TTP deficiency phenotype in mice, we created a mouse model in which TTP lacked its CNBD. CNBD deletion mice exhibited a less severe phenotype than the complete TTP KO mice. In macrophages, the stabilization of target transcripts seen in KO mice was partially normalized in the CNBD deletion mice. In cell-free experiments, recombinant TTP lacking its CNBD could still activate target mRNA deadenylation by purified recombinant Schizosaccharomyces pombe CCR4/NOT complexes, although to a lesser extent than full-length TTP. Thus, TTP lacking its CNBD can still act to promote target mRNA instability in vitro and in vivo These data have implications for TTP family members throughout the eukarya, since species from all four kingdoms contain proteins with linked TZF and CNOT1 binding domains.
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Affiliation(s)
- Wi S Lai
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Deborah J Stumpo
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Melissa L Wells
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Artiom Gruzdev
- Reproductive & Developmental Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Stephanie N Hicks
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Cindo O Nicholson
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Zhengfeng Yang
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, USA
- Shriners Hospitals for Children, St. Louis, Missouri, USA
| | - Roberta Faccio
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, USA
- Shriners Hospitals for Children, St. Louis, Missouri, USA
| | | | - Lori A Passmore
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Perry J Blackshear
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
- Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
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10
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Lai WS, Wells ML, Perera L, Blackshear PJ. The tandem zinc finger RNA binding domain of members of the tristetraprolin protein family. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1531. [PMID: 30864256 DOI: 10.1002/wrna.1531] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 02/12/2019] [Accepted: 02/20/2019] [Indexed: 12/23/2022]
Abstract
Tristetraprolin (TTP), the prototype member of the protein family of the same name, was originally discovered as the product of a rapidly inducible gene in mouse cells. Development of a knockout (KO) mouse established that absence of the protein led to a severe inflammatory syndrome, due in part to elevated levels of tumor necrosis factor (TNF). TTP was found to bind directly and with high affinity to specific AU-rich sequences in the 3'-untranslated region of the TNF mRNA. This initial binding led to promotion of TNF mRNA decay and inhibition of its translation. Many additional TTP target mRNAs have since been identified, some of which are cytokines and chemokines involved in the inflammatory response. There are three other proteins in the mouse with similar activities and domain structures, but whose KO phenotypes are remarkably different. Moreover, proteins with similar domain structures and activities have been found throughout eukaryotes, demonstrating that this protein family arose from an ancient ancestor. The defining characteristic of this protein family is the tandem zinc finger (TZF) domain, a 64 amino acid sequence with many conserved residues that is responsible for the direct RNA binding. We discuss here many aspects of this protein domain that have been elucidated since the original discovery of TTP, including its sequence conservation throughout eukarya; its apparent continued evolution in some lineages; its functional dependence on many key conserved residues; its "interchangeability" among evolutionarily distant species; and the evidence that RNA binding is required for the physiological functions of the proteins. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Wi S Lai
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Durham, North Carolina
| | - Melissa L Wells
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Durham, North Carolina
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Durham, North Carolina
| | - Perry J Blackshear
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Durham, North Carolina.,Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, North Carolina
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11
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Webster MW, Stowell JA, Passmore LA. RNA-binding proteins distinguish between similar sequence motifs to promote targeted deadenylation by Ccr4-Not. eLife 2019; 8:40670. [PMID: 30601114 PMCID: PMC6340701 DOI: 10.7554/elife.40670] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 12/28/2018] [Indexed: 12/17/2022] Open
Abstract
The Ccr4-Not complex removes mRNA poly(A) tails to regulate eukaryotic mRNA stability and translation. RNA-binding proteins contribute to specificity by interacting with both Ccr4-Not and target mRNAs, but this is not fully understood. Here, we reconstitute accelerated and selective deadenylation of RNAs containing AU-rich elements (AREs) and Pumilio-response elements (PREs). We find that the fission yeast homologues of Tristetraprolin/TTP and Pumilio/Puf (Zfs1 and Puf3) interact with Ccr4-Not via multiple regions within low-complexity sequences, suggestive of a multipartite interface that extends beyond previously defined interactions. Using a two-color assay to simultaneously monitor poly(A) tail removal from different RNAs, we demonstrate that Puf3 can distinguish between RNAs of very similar sequence. Analysis of binding kinetics reveals that this is primarily due to differences in dissociation rate constants. Consequently, motif quality is a major determinant of mRNA stability for Puf3 targets in vivo and can be used for the prediction of mRNA targets. When a cell needs to make a particular protein, it first copies the instructions from the matching gene into a molecule known as a messenger RNA (or an mRNA for short). The more mRNA copies it makes, the more protein it can produce. A simple way to control protein production is to raise or lower the number of these mRNA messages, and living cells have lots of ways to make this happen. One method involves codes built into the mRNAs themselves. The mRNAs can carry short sequences of genetic letters that can trigger their own destruction. Known as “destabilising motifs”, these sequences attract the attention of a group of proteins called Ccr4-Not. Together these proteins shorten the end of the mRNAs, preparing the molecules for degradation. But how does Ccr4-Not choose which mRNAs to target? Different mRNAs carry different destabilising motifs. This means that when groups of mRNAs all carry the same motif, the cell can destroy them all together. This allows the cell to switch networks of related genes off together without affecting the mRNAs it still needs. What is puzzling is that the destabilising motifs that control different groups of mRNAs can be very similar, and scientists do not yet know how Ccr4-Not can tell the difference, or what triggers it to start breaking down groups of mRNAs. To find out, Webster et al. recreated the system in the laboratory using purified molecules. The test-tube system confirmed previous suggestions that a protein called Puf3 forms a bridge between Ccr4-Not and mRNAs. It acts as a tether, recognising a destabilising motif and linking it to Ccr4-Not. Labelling different mRNAs with two colours of fluorescent dye showed how Puf3 helps the cell to choose which to destroy. Puf3 allows Ccr4-Not to select specific mRNAs from a mixture of molecules. Puf3 could distinguish between mRNAs that differed in a single letter of genetic code. When it matched with the wrong mRNA, it disconnected much faster than when it matched with the right one, preventing Ccr4-Not from linking up. The ability to destroy specific mRNA messages is critical for cell survival. It happens when cells divide, during immune responses such as inflammation, and in early development. Understanding the targets of tethers like Puf3 could help scientists to predict which genes will switch off and when. This could reveal genes that work together, helping to unravel their roles inside cells.
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Affiliation(s)
| | | | - Lori A Passmore
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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12
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Schmidt JA, Danielson KG, Duffner ER, Radecki SG, Walker GT, Shelton A, Wang T, Knepper JE. Regulation of the oncogenic phenotype by the nuclear body protein ZC3H8. BMC Cancer 2018; 18:759. [PMID: 30041613 PMCID: PMC6057032 DOI: 10.1186/s12885-018-4674-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 07/18/2018] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND The Zc3h8 gene encodes a protein with three zinc finger motifs in the C-terminal region. The protein has been identified as a component of the Little Elongation Complex, involved in transcription of small nuclear RNAs. ZC3H8 is overexpressed in a number of human and mouse breast cancer cell lines, and elevated mRNA levels are associated with a poorer prognosis for women with breast cancer. METHODS We used RNA silencing to decrease levels of expression in mouse mammary tumor cells and overexpression of ZC3H8 in cells derived from the normal mouse mammary gland. We measured characteristics of cell behavior in vitro, including proliferation, migration, invasion, growth in soft agar, and spheroid growth. We assessed the ability of these cells to form tumors in syngeneic BALB/c mice. ZC3H8 protein was visualized in cells using confocal microscopy. RESULTS Tumor cells with lower ZC3H8 expression exhibited decreased proliferation rates, slower migration, reduced ability to invade through a basement membrane, and decreased anchorage independent growth in vitro. Cells with lower ZC3H8 levels formed fewer and smaller tumors in animals. Overexpression of ZC3H8 in non-tumorigenic COMMA-D cells led to an opposite effect. ZC3H8 protein localized to both PML bodies and Cajal bodies within the nucleus. ZC3H8 has a casein kinase 2 (CK2) phosphorylation site near the N-terminus, and a CK2 inhibitor caused the numerous PML bodies and ZC3H8 to coalesce to a few larger bodies. Removal of the inhibitor restored PML bodies to their original state. A mutant ZC3H8 lacking the predicted CK2 phosphorylation site showed localization and numbers of ZC3H8/PML bodies similar to wild type. In contrast, a mutant constructed with a glutamic acid in place of the phosphorylatable threonine showed dramatically increased numbers of smaller nuclear foci. CONCLUSIONS These experiments demonstrate that Zc3h8 expression contributes to aggressive tumor cell behavior in vitro and in vivo. Our studies show that ZC3H8 integrity is key to maintenance of PML bodies. The work provides a link between the Little Elongation Complex, PML bodies, and the cancer cell phenotype.
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Affiliation(s)
- John A. Schmidt
- Department of Biology, Mendel Science Center, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 USA
| | - Keith G. Danielson
- Department of Biology, Mendel Science Center, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 USA
| | - Emily R. Duffner
- Department of Biology, Mendel Science Center, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 USA
| | - Sara G. Radecki
- Department of Biology, Mendel Science Center, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 USA
| | - Gerard T. Walker
- Department of Biology, Mendel Science Center, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 USA
| | - Amber Shelton
- Department of Biology, Mendel Science Center, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 USA
| | - Tianjiao Wang
- Department of Biology, Mendel Science Center, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 USA
| | - Janice E. Knepper
- Department of Biology, Mendel Science Center, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 USA
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13
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Navarro FJ, Chakravarty P, Nurse P. Phosphorylation of the RNA-binding protein Zfs1 modulates sexual differentiation in fission yeast. J Cell Sci 2017; 130:4144-4154. [PMID: 29084823 PMCID: PMC5769579 DOI: 10.1242/jcs.208066] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 10/24/2017] [Indexed: 12/21/2022] Open
Abstract
Sexual differentiation in the fission yeast Schizosaccharomyces pombe promotes cell cycle arrest and extensive changes in gene expression, resulting in cell-to-cell fusion, the exchange of hereditary material and specialized cell division. These events are detrimental to the cell if they are triggered in inappropriate conditions, and therefore the decision to differentiate must be precisely controlled. Here, we investigated the role of the RNA-binding protein Zfs1 in this process by identifying its targets and characterizing novel post-translational regulatory mechanisms. We found that Zfs1 negatively regulates the G1 cyclin Puc1, and deregulated Puc1 levels inhibit differentiation in the zfs1Δ mutant. We also found that Zfs1 undergoes phosphorylation, which is stimulated upon nitrogen depletion or inhibition of the TOR pathway. Phosphorylation of Zfs1 modulates accumulation of Puc1 and plays an important role in the response of the cell to sexual differentiation signals. We propose that Zfs1 functions as an integrator of nutrient information to modulate sexual differentiation, contributing to the establishment of the differentiation-activating threshold.
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Affiliation(s)
| | - Probir Chakravarty
- Bioinformatics, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Paul Nurse
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK
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14
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Wells ML, Perera L, Blackshear PJ. An Ancient Family of RNA-Binding Proteins: Still Important! Trends Biochem Sci 2017; 42:285-296. [PMID: 28096055 DOI: 10.1016/j.tibs.2016.12.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 12/22/2022]
Abstract
RNA-binding proteins are important modulators of mRNA stability, a crucial process that determines the ultimate cellular levels of mRNAs and their encoded proteins. The tristetraprolin (TTP) family of RNA-binding proteins appeared early in the evolution of eukaryotes, and has persisted in modern eukaryotes. The domain structures and biochemical functions of family members from widely divergent lineages are remarkably similar, but their mRNA 'targets' can be very different, even in closely related species. Recent gene knockout studies in species as distantly related as plants, flies, yeasts, and mice have demonstrated crucial roles for these proteins in a wide variety of physiological processes. Inflammatory and hematopoietic phenotypes in mice have suggested potential therapeutic approaches for analogous human disorders.
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Affiliation(s)
- Melissa L Wells
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Perry J Blackshear
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA; Departments of Biochemistry and Medicine, Duke University Medical Center, Durham, NC 27710, USA.
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15
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A Novel Hybrid Iron Regulation Network Combines Features from Pathogenic and Nonpathogenic Yeasts. mBio 2016; 7:mBio.01782-16. [PMID: 27795405 PMCID: PMC5082906 DOI: 10.1128/mbio.01782-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Iron is an essential micronutrient for both pathogens and their hosts, which restrict iron availability during infections in an effort to prevent microbial growth. Successful human pathogens like the yeast Candida glabrata have thus developed effective iron acquisition strategies. Their regulation has been investigated well for some pathogenic fungi and in the model organism Saccharomyces cerevisiae, which employs an evolutionarily derived system. Here, we show that C. glabrata uses a regulation network largely consisting of components of the S. cerevisiae regulon but also of elements of other pathogenic fungi. Specifically, similarly to baker's yeast, Aft1 is the main positive regulator under iron starvation conditions, while Cth2 degrades mRNAs encoding iron-requiring enzymes. However, unlike the case with S. cerevisiae, a Sef1 ortholog is required for full growth under iron limitation conditions, making C. glabrata an evolutionary intermediate to SEF1-dependent fungal pathogens. Therefore, C. glabrata has evolved an iron homeostasis system which seems to be unique within the pathogenic fungi. IMPORTANCE The fungus Candida glabrata represents an evolutionarily close relative of the well-studied and benign baker's yeast and model organism Saccharomyces cerevisiae On the other hand, C. glabrata is an important opportunistic human pathogen causing both superficial and systemic infections. The ability to acquire trace metals, in particular, iron, and to tightly regulate this process during infection is considered an important virulence attribute of a variety of pathogens. Importantly, S. cerevisiae uses a highly derivative regulatory system distinct from those of other fungi. Until now, the regulatory mechanism of iron homeostasis in C. glabrata has been mostly unknown. Our study revealed a hybrid iron regulation network that is unique to C. glabrata and is placed at an evolutionary midpoint between those of S. cerevisiae and related fungal pathogens. We thereby show that, in the host, even a successful human pathogen can rely largely on a strategy normally found in nonpathogenic fungi from a terrestrial environment.
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16
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Převorovský M, Oravcová M, Tvarůžková J, Zach R, Folk P, Půta F, Bähler J. Fission Yeast CSL Transcription Factors: Mapping Their Target Genes and Biological Roles. PLoS One 2015; 10:e0137820. [PMID: 26366556 PMCID: PMC4569565 DOI: 10.1371/journal.pone.0137820] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 08/24/2015] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Cbf11 and Cbf12, the fission yeast CSL transcription factors, have been implicated in the regulation of cell-cycle progression, but no specific roles have been described and their target genes have been only partially mapped. METHODOLOGY/PRINCIPAL FINDINGS Using a combination of transcriptome profiling under various conditions and genome-wide analysis of CSL-DNA interactions, we identify genes regulated directly and indirectly by CSL proteins in fission yeast. We show that the expression of stress-response genes and genes that are expressed periodically during the cell cycle is deregulated upon genetic manipulation of cbf11 and/or cbf12. Accordingly, the coordination of mitosis and cytokinesis is perturbed in cells with genetically manipulated CSL protein levels, together with other specific defects in cell-cycle progression. Cbf11 activity is nutrient-dependent and Δcbf11-associated defects are mitigated by inactivation of the protein kinase A (Pka1) and stress-activated MAP kinase (Sty1p38) pathways. Furthermore, Cbf11 directly regulates a set of lipid metabolism genes and Δcbf11 cells feature a stark decrease in the number of storage lipid droplets. CONCLUSIONS/SIGNIFICANCE Our results provide a framework for a more detailed understanding of the role of CSL proteins in the regulation of cell-cycle progression in fission yeast.
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Affiliation(s)
- Martin Převorovský
- Research Department of Genetics, Evolution & Environment and UCL Cancer Institute, University College London, London, United Kingdom
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Martina Oravcová
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jarmila Tvarůžková
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Róbert Zach
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Petr Folk
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - František Půta
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jürg Bähler
- Research Department of Genetics, Evolution & Environment and UCL Cancer Institute, University College London, London, United Kingdom
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17
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Wells ML, Hicks SN, Perera L, Blackshear PJ. Functional equivalence of an evolutionarily conserved RNA binding module. J Biol Chem 2015; 290:24413-23. [PMID: 26292216 DOI: 10.1074/jbc.m115.673012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Indexed: 11/06/2022] Open
Abstract
Members of the tristetraprolin (TTP) family of proteins participate in the regulation of mRNA turnover after initially binding to AU-rich elements in target mRNAs. Related proteins from most groups of eukaryotes contain a conserved tandem zinc finger (TZF) domain consisting of two closely spaced, similar CCCH zinc fingers that form the primary RNA binding domain. There is considerable sequence variation within the TZF domains from different family members within a single organism and from different organisms, raising questions about sequence-specific effects on RNA binding and decay promotion. We hypothesized that TZF domains from evolutionarily distant species are functionally interchangeable. The single family member expressed in the fission yeast Schizosaccharomyces pombe, Zfs1, promotes the turnover of several dozen transcripts, some of which are involved in cell-cell interactions. Using knockin techniques, we replaced the TZF domain of S. pombe Zfs1 with the equivalent domains from human TTP and the single family member proteins expressed in the silkworm Bombyx mori, the pathogenic yeast Candida guilliermondii, and the plant Chromolaena odorata. We found that the TZF domains from these widely disparate species could completely substitute for the native S. pombe TZF domain, as determined by measurement of target transcript levels and the flocculation phenotype characteristic of Zfs1 deletion. Recombinant TZF domain peptides from several of these species bound to an AU-rich RNA oligonucleotide with comparably high affinity. We conclude that the TZF domains from TTP family members in these evolutionarily widely divergent species are functionally interchangeable in mRNA binding and decay.
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Affiliation(s)
| | | | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, NIEHS/National Institutes of Health, Research Triangle Park, North Carolina 27709 and
| | - Perry J Blackshear
- From the Signal Transduction Laboratory and Departments of Medicine and Biochemistry, Duke University, Medical Center, Durham, North Carolina 27710
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18
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Blackshear PJ, Perera L. Phylogenetic distribution and evolution of the linked RNA-binding and NOT1-binding domains in the tristetraprolin family of tandem CCCH zinc finger proteins. J Interferon Cytokine Res 2015; 34:297-306. [PMID: 24697206 DOI: 10.1089/jir.2013.0150] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In humans, the tristetraprolin or TTP family of CCCH tandem zinc finger (TZF) proteins comprises 3 members, encoded by the genes ZFP36, ZFP36L1, and ZFP36L2. These proteins have direct orthologues in essentially all vertebrates studied, with the exception of birds, which appear to lack a version of ZFP36. Additional family members are found in rodents, amphibians, and fish. In general, the encoded proteins contain 2 critical macromolecular interaction domains: the CCCH TZF domain, which is necessary for high-affinity binding to AU-rich elements in mRNA; and an extreme C-terminal domain that, in the case of TTP, interacts with NOT1, the scaffold of a large multi-protein complex that contains deadenylases. TTP and its related proteins act by first binding to AU-rich elements in mRNA, and then recruiting deadenylases to the mRNA, where they can processively remove the adenosine residues from the poly(A) tail. Highly conserved TZF domains have been found in unicellular eukaryotes such as yeasts, and these domains can bind AU-rich elements that resemble those bound by the mammalian proteins. However, certain fungi appear to lack proteins with intact TZF domains, and the TTP family proteins that are expressed in other fungi often lack the characteristic C-terminal NOT1 binding domain found in the mammalian proteins. For these reasons, we investigated the phylogenetic distribution of the relevant sequences in available databases. Both domains are present in family member proteins from most lineages of eukaryotes, suggesting their mutual presence in a common ancestor. However, the vertebrate type of NOT1-binding domain is missing in most fungi, and the TZF domain itself has disappeared or degenerated in recently evolved fungi. Nonetheless, both domains are present together in the proteins from several unicellular eukaryotes, including at least 1 fungus, and they seem to have remained together during the evolution of metazoans.
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Affiliation(s)
- Perry J Blackshear
- 1 Laboratories of Signal Transduction, National Institute of Environmental Health Sciences , Research Triangle Park, North Carolina
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19
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Wells ML, Washington OL, Hicks SN, Nobile CJ, Hartooni N, Wilson GM, Zucconi BE, Huang W, Li L, Fargo DC, Blackshear PJ. Post-transcriptional regulation of transcript abundance by a conserved member of the tristetraprolin family in Candida albicans. Mol Microbiol 2015; 95:1036-53. [PMID: 25524641 DOI: 10.1111/mmi.12913] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2014] [Indexed: 11/29/2022]
Abstract
Members of the tristetraprolin (TTP) family of CCCH tandem zinc finger proteins bind to AU-rich regions in target mRNAs, leading to their deadenylation and decay. Family members in Saccharomyces cerevisiae influence iron metabolism, whereas the single protein expressed in Schizosaccharomyces pombe, Zfs1, regulates cell-cell interactions. In the human pathogen Candida albicans, deep sequencing of mutants lacking the orthologous protein, Zfs1, revealed significant increases (> 1.5-fold) in 156 transcripts. Of these, 113 (72%) contained at least one predicted TTP family member binding site in their 3'UTR, compared with only 3 of 56 (5%) down-regulated transcripts. The zfs1Δ/Δ mutant was resistant to 3-amino-1,2,4-triazole, perhaps because of increased expression of the potential target transcript encoded by HIS3. Sequences of the proteins encoded by the putative Zfs1 targets were highly conserved among other species within the fungal CTG clade, while the predicted Zfs1 binding sites in these mRNAs often 'disappeared' with increasing evolutionary distance from the parental species. C. albicans Zfs1 bound to the ideal mammalian TTP binding site with high affinity, and Zfs1 was associated with target transcripts after co-immunoprecipitation. Thus, the biochemical activities of these proteins in fungi are highly conserved, but Zfs1-like proteins may target different transcripts in each species.
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Affiliation(s)
- Melissa L Wells
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
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20
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Choi YJ, Lai WS, Fedic R, Stumpo DJ, Huang W, Li L, Perera L, Brewer BY, Wilson GM, Mason JM, Blackshear PJ. The Drosophila Tis11 protein and its effects on mRNA expression in flies. J Biol Chem 2014; 289:35042-60. [PMID: 25342740 DOI: 10.1074/jbc.m114.593491] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Members of the mammalian tristetraprolin family of CCCH tandem zinc finger proteins can bind to certain AU-rich elements (AREs) in mRNAs, leading to their deadenylation and destabilization. Mammals express three or four members of this family, but Drosophila melanogaster and other insects appear to contain a single gene, Tis11. We found that recombinant Drosophila Tis11 protein could bind to ARE-containing RNA oligonucleotides with low nanomolar affinity. Remarkably, co-expression in mammalian cells with "target" RNAs demonstrated that Tis11 could promote destabilization of ARE-containing mRNAs and that this was partially dependent on a conserved C-terminal sequence resembling the mammalian NOT1 binding domain. Drosophila Tis11 promoted both deadenylation and decay of a target transcript in this heterologous cell system. We used chromosome deletion/duplication and P element insertion to produce two types of Tis11 deficiency in adult flies, both of which were viable and fertile. To address the hypothesis that Tis11 deficiency would lead to the abnormal accumulation of potential target transcripts, we analyzed gene expression in adult flies by deep mRNA sequencing. We identified 69 transcripts from 56 genes that were significantly up-regulated more than 1.5-fold in both types of Tis11-deficient flies. Ten of the up-regulated transcripts encoded probable proteases, but many other functional classes of proteins were represented. Many of the up-regulated transcripts contained potential binding sites for tristetraprolin family member proteins that were conserved in other Drosophila species. Tis11 is thus an ARE-binding, mRNA-destabilizing protein that may play a role in post-transcriptional gene expression in Drosophila and other insects.
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Affiliation(s)
| | - Wi S Lai
- From the Laboratories of Signal Transduction
| | | | | | | | | | - Lalith Perera
- Structural Biology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Brandy Y Brewer
- the Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland 21201, and
| | - Gerald M Wilson
- the Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland 21201, and
| | | | - Perry J Blackshear
- From the Laboratories of Signal Transduction, the Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, North Carolina 27710
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21
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Fraser HB. Cell-cycle regulated transcription associates with DNA replication timing in yeast and human. Genome Biol 2014; 14:R111. [PMID: 24098959 PMCID: PMC3983658 DOI: 10.1186/gb-2013-14-10-r111] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 09/20/2013] [Indexed: 11/25/2022] Open
Abstract
Background Eukaryotic DNA replication follows a specific temporal program, with some genomic regions consistently replicating earlier than others, yet what determines this program is largely unknown. Highly transcribed regions have been observed to replicate in early S-phase in all plant and animal species studied to date, but this relationship is thought to be absent from both budding yeast and fission yeast. No association between cell-cycle regulated transcription and replication timing has been reported for any species. Results Here I show that in budding yeast, fission yeast, and human, the genes most highly transcribed during S-phase replicate early, whereas those repressed in S-phase replicate late. Transcription during other cell-cycle phases shows either the opposite correlation with replication timing, or no relation. The relationship is strongest near late-firing origins of replication, which is not consistent with a previously proposed model—that replication timing may affect transcription—and instead suggests a potential mechanism involving the recruitment of limiting replication initiation factors during S-phase. Conclusions These results suggest that S-phase transcription may be an important determinant of DNA replication timing across eukaryotes, which may explain the well-established association between transcription and replication timing.
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22
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Oravcová M, Teska M, Půta F, Folk P, Převorovský M. Fission yeast CSL proteins function as transcription factors. PLoS One 2013; 8:e59435. [PMID: 23555033 PMCID: PMC3598750 DOI: 10.1371/journal.pone.0059435] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 02/14/2013] [Indexed: 12/29/2022] Open
Abstract
Background Transcription factors of the CSL (CBF1/RBP-Jk/Suppressor of Hairless/LAG-1) family are key regulators of metazoan development and function as the effector components of the Notch receptor signalling pathway implicated in various cell fate decisions. CSL proteins recognize specifically the GTG[G/A]AA sequence motif and several mutants compromised in their ability to bind DNA have been reported. In our previous studies we have identified a number of novel putative CSL family members in fungi, organisms lacking the Notch pathway. It is not clear whether these represent genuine CSL family members. Methodology/Principal Findings Using a combination of in vitro and in vivo approaches we characterized the DNA binding properties of Cbf11 and Cbf12, the antagonistic CSL paralogs from the fission yeast, important for the proper coordination of cell cycle events and the regulation of cell adhesion. We have shown that a mutation of a conserved arginine residue abolishes DNA binding in both CSL paralogs, similar to the situation in mouse. We have also demonstrated the ability of Cbf11 and Cbf12 to activate gene expression in an autologous fission yeast reporter system. Conclusions/Significance Our results indicate that the fission yeast CSL proteins are indeed genuine family members capable of functioning as transcription factors, and provide support for the ancient evolutionary origin of this important protein family.
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Affiliation(s)
- Martina Oravcová
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Mikoláš Teska
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - František Půta
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Petr Folk
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Martin Převorovský
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- * E-mail:
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