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Chen L, Liu J, Chen K, Su Y, Chen Y, Lei Y, Si J, Zhang J, Zhang Z, Zou W, Zhang X, Rondina MT, Wang QF, Li Y. SET domain containing 2 promotes megakaryocyte polyploidization and platelet generation through methylation of α-tubulin. J Thromb Haemost 2024; 22:1727-1741. [PMID: 38537781 DOI: 10.1016/j.jtha.2024.03.010] [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: 08/29/2023] [Revised: 02/23/2024] [Accepted: 03/12/2024] [Indexed: 04/26/2024]
Abstract
BACKGROUND Megakaryocytes (MKs) are polyploid cells responsible for producing ∼1011 platelets daily in humans. Unraveling the mechanisms regulating megakaryopoiesis holds the promise for the production of clinical-grade platelets from stem cells, overcoming significant current limitations in platelet transfusion medicine. Previous work identified that loss of the epigenetic regulator SET domain containing 2 (SETD2) was associated with an increased platelet count in mice. However, the role of SETD2 in megakaryopoiesis remains unknown. OBJECTIVES Here, we examined how SETD2 regulated MK development and platelet production using complementary murine and human systems. METHODS We manipulated the expression of SETD2 in multiple in vitro and ex vivo models to assess the ploidy of MKs and the function of platelets. RESULTS The genetic ablation of Setd2 increased the number of high-ploidy bone marrow MKs. Peripheral platelet counts in Setd2 knockout mice were significantly increased ∼2-fold, and platelets exhibited normal size, morphology, and function. By knocking down and overexpressing SETD2 in ex vivo human cell systems, we demonstrated that SETD2 negatively regulated MK polyploidization by controlling methylation of α-tubulin, microtubule polymerization, and MK nuclear division. Small-molecule inactivation of SETD2 significantly increased the production of high-ploidy MKs and platelets from human-induced pluripotent stem cells and cord blood CD34+ cells. CONCLUSION These findings identify a previously unrecognized role for SETD2 in regulating megakaryopoiesis and highlight the potential of targeting SETD2 to increase platelet production from human cells for transfusion practices.
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Affiliation(s)
- Lei Chen
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jingkun Liu
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Kunying Chen
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yanxun Su
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yihe Chen
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Ying Lei
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jia Si
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jie Zhang
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Zhaojun Zhang
- University of Chinese Academy of Sciences, Beijing, China; Key Laboratory of Genome Science and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, China National Center of Bioinformation, Beijing, China; Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
| | - Weiguo Zou
- Shanghai Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China; State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Xiaohui Zhang
- Peking University People's Hospital, Peking University Institute of Hematology, Beijing, China; National Clinical Research Center for Hematologic Disease, Beijing, China; Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Beijing, China; Collaborative Innovation Center of Hematology, Peking University, Beijing, China
| | - Matthew T Rondina
- Departments of Internal Medicine and Pathology, Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA; Department of Internal Medicine and the Geriatric Research, Education, and Clinical Center, George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah, USA.
| | - Qian-Fei Wang
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
| | - Yueying Li
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
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Mitchell B, Thor S, Piper M. Cellular and molecular functions of SETD2 in the central nervous system. J Cell Sci 2023; 136:jcs261406. [PMID: 37921122 DOI: 10.1242/jcs.261406] [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] [Indexed: 11/04/2023] Open
Abstract
The covalent modification of histones is critical for many biological functions in mammals, including gene regulation and chromatin structure. Posttranslational histone modifications are added and removed by specialised 'writer' and 'eraser' enzymes, respectively. One such writer protein implicated in a wide range of cellular processes is SET domain-containing 2 (SETD2), a histone methyltransferase that catalyses the trimethylation of lysine 36 on histone H3 (H3K36me3). Recently, SETD2 has also been found to modify proteins other than histones, including actin and tubulin. The emerging roles of SETD2 in the development and function of the mammalian central nervous system (CNS) are of particular interest as several SETD2 variants have been implicated in neurodevelopmental disorders, such as autism spectrum disorder and the overgrowth disorder Luscan-Lumish syndrome. Here, we summarise the numerous roles of SETD2 in mammalian cellular functions and development, with a focus on the CNS. We also provide an overview of the consequences of SETD2 variants in human disease and discuss future directions for understanding essential cellular functions of SETD2.
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Affiliation(s)
- Benjamin Mitchell
- The School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Stefan Thor
- The School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Michael Piper
- The School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
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3
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Bushara O, Wester JR, Jacobsen D, Sun L, Weinberg S, Gao J, Jennings LJ, Wang L, Lauberth SM, Yue F, Liao J, Yang GY. Clinical and histopathologic characterization of SETD2-mutated colorectal cancer. Hum Pathol 2023; 131:9-16. [PMID: 36502925 PMCID: PMC9875556 DOI: 10.1016/j.humpath.2022.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 12/03/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022]
Abstract
With the advent of next-generation sequencing (NGS), identifying and better understanding genetic mutations in cancer pathways has become more feasible. A mutation now commonly reported in NGS panels is the SETD2 gene (H3K36 trimethyltransferase). However, its contributions to colorectal cancer (CRC) are not well described. In this study, we describe the clinicopathologic characteristics of SETD2-mutated CRC, determine common mutation sites on the SETD2 gene, and correlate these mutations with the loss of H3K36 trimethylation and the aberrant expression of beta-catenin. By searching pathology reports at our institution which included the 161-gene NGS panel from 2019 to 2021, we identify 24 individuals with SETD2-mutated CRC. All samples were evaluated for microsatellite status, H3K36 trimethylation, and beta-catenin via immunohistochemistry. In this cohort of 24 SETD2-mutated CRC individuals (a median age of 62.4 years [interquartile range: 49.1-73.6]), 10 (41.7%) patients presented at American Joint Committee on Cancer (AJCC) tumor stage II, seven (29.2%) at stage III, six (25%) at stage IV, and one (4.2%) at stage I. Most tumors studied were adenocarcinomas with no further specification (22, 92%), and most tumors were microsatellite stable (18, 82.5%). Thirty-three mutation locations were represented by 24 patients, with one patient having six mutations in the SETD2 gene and two patients having three mutations. The dominant mutation type is missense mutations (N = 29, 87.9%), and no mutation hotspots were found. Only two samples lost trimethylation of histone H3K36, both from individuals with multiple SETD2 mutations and aberrant nuclear beta-catenin expression. SETD2-mutated CRC is similar in clinical and histologic presentation to other commonly reported CRC. SETD2 mutations were missense dominantand showed no hotspots, and multiple mutations are likely necessary for loss of H3K36 trimethylation. These results warrant further study on determining a role of SETD2-histone H3K36 pathway in CRC.
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Affiliation(s)
- Omar Bushara
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - James R Wester
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - Danielle Jacobsen
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - Leyu Sun
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - Samuel Weinberg
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - Juehua Gao
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - Lawrence J Jennings
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - Lu Wang
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - Shannon M Lauberth
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - Feng Yue
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - Jie Liao
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
| | - Guang-Yu Yang
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA.
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4
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Leung W, Teater M, Durmaz C, Meydan C, Chivu AG, Chadburn A, Rice EJ, Muley A, Camarillo JM, Arivalagan J, Li Z, Flowers CR, Kelleher NL, Danko CG, Imielinski M, Dave SS, Armstrong SA, Mason CE, Melnick AM. SETD2 Haploinsufficiency Enhances Germinal Center-Associated AICDA Somatic Hypermutation to Drive B-cell Lymphomagenesis. Cancer Discov 2022; 12:1782-1803. [PMID: 35443279 PMCID: PMC9262862 DOI: 10.1158/2159-8290.cd-21-1514] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 03/08/2022] [Accepted: 04/18/2022] [Indexed: 01/26/2023]
Abstract
SETD2 is the sole histone methyltransferase responsible for H3K36me3, with roles in splicing, transcription initiation, and DNA damage response. Homozygous disruption of SETD2 yields a tumor suppressor effect in various cancers. However, SETD2 mutation is typically heterozygous in diffuse large B-cell lymphomas. Here we show that heterozygous Setd2 deficiency results in germinal center (GC) hyperplasia and increased competitive fitness, with reduced DNA damage checkpoint activity and apoptosis, resulting in accelerated lymphomagenesis. Impaired DNA damage sensing in Setd2-haploinsufficient germinal center B (GCB) and lymphoma cells associated with increased AICDA-induced somatic hypermutation, complex structural variants, and increased translocations including those activating MYC. DNA damage was selectively increased on the nontemplate strand, and H3K36me3 loss was associated with greater RNAPII processivity and mutational burden, suggesting that SETD2-mediated H3K36me3 is required for proper sensing of cytosine deamination. Hence, Setd2 haploinsufficiency delineates a novel GCB context-specific oncogenic pathway involving defective epigenetic surveillance of AICDA-mediated effects on transcribed genes. SIGNIFICANCE Our findings define a B cell-specific oncogenic effect of SETD2 heterozygous mutation, which unleashes AICDA mutagenesis of nontemplate strand DNA in the GC reaction, resulting in lymphomas with heavy mutational burden. GC-derived lymphomas did not tolerate SETD2 homozygous deletion, pointing to a novel context-specific therapeutic vulnerability. This article is highlighted in the In This Issue feature, p. 1599.
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Affiliation(s)
- Wilfred Leung
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medicine, Cornell University, New York, New York
- Department of Biomedical Sciences, Cornell University, Ithaca, New York
| | - Matt Teater
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medicine, Cornell University, New York, New York
| | - Ceyda Durmaz
- Graduate Program of Physiology, Biophysics and Systems Biology, Weill Cornell Medicine, New York, New York
| | - Cem Meydan
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, New York
- The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Cornell Medicine, New York, New York
- The WorldQuant Initiative for Quantitative Prediction, Weill Cornell Medicine, New York, New York
| | - Alexandra G Chivu
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Amy Chadburn
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York
| | - Edward J Rice
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Ashlesha Muley
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medicine, Cornell University, New York, New York
| | - Jeannie M Camarillo
- Departments of Chemistry, Molecular Biosciences and the National Resource for Translational and Developmental Proteomics, Northwestern University, Evanston, Illinois
| | - Jaison Arivalagan
- Departments of Chemistry, Molecular Biosciences and the National Resource for Translational and Developmental Proteomics, Northwestern University, Evanston, Illinois
| | - Ziyi Li
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Christopher R Flowers
- Department of Lymphoma and Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Neil L Kelleher
- Departments of Chemistry, Molecular Biosciences and the National Resource for Translational and Developmental Proteomics, Northwestern University, Evanston, Illinois
| | - Charles G Danko
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Marcin Imielinski
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York
- New York Genome Center, New York, New York
- Caryl and Israel Englander Institute for Precision Medicine and Meyer Cancer Center, Weill Cornell Medicine, New York, New York
| | - Sandeep S Dave
- Center for Genomic and Computational Biology and Department of Medicine, Duke University, Durham, North Carolina
| | - Scott A Armstrong
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Christopher E Mason
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, New York
- The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Cornell Medicine, New York, New York
- The WorldQuant Initiative for Quantitative Prediction, Weill Cornell Medicine, New York, New York
- The Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York
| | - Ari M Melnick
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medicine, Cornell University, New York, New York
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5
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Chen F, Chen J, Wang H, Tang H, Huang L, Wang S, Wang X, Fang X, Liu J, Li L, Ouyang K, Han Z. Histone Lysine Methyltransferase SETD2 Regulates Coronary Vascular Development in Embryonic Mouse Hearts. Front Cell Dev Biol 2021; 9:651655. [PMID: 33898448 PMCID: PMC8063616 DOI: 10.3389/fcell.2021.651655] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/04/2021] [Indexed: 11/13/2022] Open
Abstract
Congenital heart defects are the most common birth defect and have a clear genetic component, yet genomic structural variations or gene mutations account for only a third of the cases. Epigenomic dynamics during human heart organogenesis thus may play a critical role in regulating heart development. However, it is unclear how histone mark H3K36me3 acts on heart development. Here we report that histone-lysine N-methyltransferase SETD2, an H3K36me3 methyltransferase, is a crucial regulator of the mouse heart epigenome. Setd2 is highly expressed in embryonic stages and accounts for a predominate role of H3K36me3 in the heart. Loss of Setd2 in cardiac progenitors results in obvious coronary vascular defects and ventricular non-compaction, leading to fetus lethality in mid-gestation, without affecting peripheral blood vessel, yolk sac, and placenta formation. Furthermore, deletion of Setd2 dramatically decreased H3K36me3 level and impacted the transcriptional landscape of key cardiac-related genes, including Rspo3 and Flrt2. Taken together, our results strongly suggest that SETD2 plays a primary role in H3K36me3 and is critical for coronary vascular formation and heart development in mice.
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Affiliation(s)
- Fengling Chen
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Jiewen Chen
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Hong Wang
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Huayuan Tang
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Lei Huang
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Shijia Wang
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Xinru Wang
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Xi Fang
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Jie Liu
- Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen, China
| | - Li Li
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, School of Medicine and Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.,School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong University, Shanghai, China
| | - Kunfu Ouyang
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Zhen Han
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
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setd2 knockout zebrafish is viable and fertile: differential and developmental stress-related requirements for Setd2 and histone H3K36 trimethylation in different vertebrate animals. Cell Discov 2020; 6:72. [PMID: 33088589 PMCID: PMC7573620 DOI: 10.1038/s41421-020-00203-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/01/2020] [Indexed: 12/21/2022] Open
Abstract
Setd2 is the only enzyme that catalyzes histone H3 lysine 36 trimethylation (H3K36me3) on virtually all actively transcribed protein-coding genes, and this mechanism is evolutionarily conserved from yeast to human. Despite this widespread and conserved activity, Setd2 and H3K36me3 are dispensable for normal growth of yeast but are absolutely required for mammalian embryogenesis, such as oocyte maturation and embryonic vasculogenesis in mice, raising a question of how the functional requirements of Setd2 in specific developmental stages have emerged through evolution. Here, we explored this issue by studying the essentiality and function of Setd2 in zebrafish. Surprisingly, the setd2-null zebrafish are viable and fertile. They show Mendelian birth ratio and normal embryogenesis without vascular defect as seen in mice; however, they have a small body size phenotype attributed to insufficient energy metabolism and protein synthesis, which is reversable in a nutrition-dependent manner. Unlike the sterile Setd2-null mice, the setd2-null zebrafish can produce functional sperms and oocytes. Nonetheless, related to the requirement of maternal Setd2 for oocyte maturation in mice, the second generation of setd2-null zebrafish that carry no maternal setd2 show decreased survival rate and a developmental delay at maternal-to-zygotic transition. Taken together, these results indicate that, while the phenotypes of the setd2-null zebrafish and mice are apparently different, they are matched in parallel as the underlying mechanisms are evolutionarily conserved. Thus, the differential requirements of Setd2 may reflect distinct viability thresholds that associate with intrinsic and/or extrinsic stresses experienced by the organism through development, and these epigenetic regulatory mechanisms may serve as a reserved source supporting the evolution of life from simplicity to complexity.
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