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Chen K, Dong Y, He G, He X, Pan M, Huang X, Yu X, Xia J. UBTF mediates activation of L3MBTL2 to suppress NISCH expression through histone H2AK119 monoubiquitination modification in breast cancer. Clin Exp Metastasis 2024:10.1007/s10585-024-10299-x. [PMID: 38935187 DOI: 10.1007/s10585-024-10299-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024]
Abstract
Lethal(3)malignant brain tumor-like protein 2 (L3MBTL2) has been related to transcriptional inhibition and chromatin compaction. Nevertheless, the biological functions and mechanisms of L3MBTL2 are undefined in breast cancer (BRCA). Here, we revealed that L3MBTL2 is responsible for the decline of Nischarin (NISCH), a well-known tumor suppressor, in BRCA, and explored the detailed mechanism. Knockdown of L3MBTL2 reduced monoubiquitination of histone H2A at lysine-119 (H2AK119ub), leading to reduced binding to the NISCH promoter and increased expression of NISCH. Meanwhile, the knockdown of L3MBTL2 decreased proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of BRCA cells, and increased apoptosis, which were abated by NISCH knockdown. Nucleolar transcription factor 1 (UBTF) induced the transcription of L3MBTL2 in BRCA, and the suppressing effects of UBTF silencing on EMT in BRCA cells were also reversed by NISCH knockdown. Knockdown of UBTF slowed tumor progression and attenuated lung tumor infiltration, whereas simultaneous knockdown of NISCH accelerated EMT and increased tumor lung metastasis. Taken together, our results show that L3MBTL2, transcriptionally activated by UBTF, exerts oncogenic functions in BRCA, by catalyzing H2AK119Ub and reducing expression of NISCH.
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Affiliation(s)
- Kun Chen
- Department of Technology and Social Services, Dazhou Vocational College of Chinese Medicine, Tongchuan District, Vocational Education Park, Dazhou, Sichuan, 635000, P.R. China
| | - Yun Dong
- Department of Traditional Chinese Medicine, Dazhou Vocational College of Chinese Medicine, Dazhou, Sichuan, 635000, P.R. China
| | - Gaojian He
- Dean's office, Dazhou Vocational College of Chinese Medicine, Dazhou, Sichuan, 635000, P.R. China
| | - Xuefeng He
- Department of Technology and Social Services, Dazhou Vocational College of Chinese Medicine, Tongchuan District, Vocational Education Park, Dazhou, Sichuan, 635000, P.R. China
| | - Meitong Pan
- Department of Technology and Social Services, Dazhou Vocational College of Chinese Medicine, Tongchuan District, Vocational Education Park, Dazhou, Sichuan, 635000, P.R. China
| | - Xuemei Huang
- Department of Oncology and Hematology, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, 646099, P.R. China
| | - Xiaolan Yu
- Department of Obstetrics and Gynecology, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, 646099, P.R. China.
| | - Jiyi Xia
- Department of Technology and Social Services, Dazhou Vocational College of Chinese Medicine, Tongchuan District, Vocational Education Park, Dazhou, Sichuan, 635000, P.R. China.
- Dazhou Chinese medicine research and development center, Dazhou, Sichuan, 635000, P.R. China.
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2
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Woods E, Holmes N, Albaba S, Evans IR, Balasubramanian M. ASXL3-related disorder: Molecular phenotyping and comprehensive review providing insights into disease mechanism. Clin Genet 2024; 105:470-487. [PMID: 38420660 DOI: 10.1111/cge.14506] [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: 01/04/2024] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 03/02/2024]
Abstract
ASXL3-related disorder, sometimes referred to as Bainbridge-Ropers syndrome, was first identified as a distinct neurodevelopmental disorder by Bainbridge et al. in 2013. Since then, there have been a number of case series and single case reports published worldwide. A comprehensive review of the literature was carried out. Abstracts were screened, relevant literature was analysed, and descriptions of common phenotypic features were quantified. ASXL3 variants were collated and categorised. Common phenotypic features comprised global developmental delay or intellectual disability (97%), feeding problems (76%), hypotonia (88%) and characteristic facial features (93%). The majority of genetic variants were de novo truncating variants in exon 11 or 12 of the ASXL3 gene. Several gaps in our knowledge of this disorder were identified, namely, underlying pathophysiology and disease mechanism, disease contribution of missense variants, relevance of variant location, prevalence and penetrance data. Clinical information is currently limited by patient numbers and lack of longitudinal data, which this review aims to address.
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Affiliation(s)
- Emily Woods
- Sheffield Clinical Genetics Service, Sheffield Children's Hospital, Sheffield, UK
- Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK
| | - Nicola Holmes
- Sheffield Diagnostic Genetics Service, Sheffield Children's Hospital, Sheffield, UK
| | - Shadi Albaba
- Sheffield Diagnostic Genetics Service, Sheffield Children's Hospital, Sheffield, UK
| | - Iwan R Evans
- Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK
- The Bateson Centre, University of Sheffield, Sheffield, UK
| | - Meena Balasubramanian
- Sheffield Clinical Genetics Service, Sheffield Children's Hospital, Sheffield, UK
- Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK
- The Bateson Centre, University of Sheffield, Sheffield, UK
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3
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Xu Z, Qin Q, Wang Y, Zhang H, Liu S, Li X, Chen Y, Wang Y, Ruan H, He W, Zhang T, Yan X, Wang C, Xu D, Jiang X. Deubiquitinase Mysm1 regulates neural stem cell proliferation and differentiation by controlling Id4 expression. Cell Death Dis 2024; 15:129. [PMID: 38342917 PMCID: PMC10859383 DOI: 10.1038/s41419-024-06530-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/13/2024]
Abstract
Neural stem cells (NSCs) are critical for brain development and maintenance of neurogenesis. However, the molecular mechanisms that regulate NSC proliferation and differentiation remain unclear. Mysm1 is a deubiquitinase and is essential for the self-renewal and differentiation of several stem cells. It is unknown whether Mysm1 plays an important role in NSCs. Here, we found that Mysm1 was expressed in NSCs and its expression was increased with age in mice. Mice with Mysm1 knockdown by crossing Mysm1 floxed mice with Nestin-Cre mice exhibited abnormal brain development with microcephaly. Mysm1 deletion promoted NSC proliferation and apoptosis, resulting in depletion of the stem cell pool. In addition, Mysm1-deficient NSCs skewed toward neurogenesis instead of astrogliogenesis. Mechanistic investigations with RNA sequencing and genome-wide CUT&Tag analysis revealed that Mysm1 epigenetically regulated Id4 transcription by regulating histone modification at the promoter region. After rescuing the expression of Id4, the hyperproliferation and imbalance differentiation of Mysm1-deficient NSCs was reversed. Additionally, knockdown Mysm1 in aged mice could promote NSC proliferation. Collectively, the present study identified a new factor Mysm1 which is essential for NSC homeostasis and Mysm1-Id4 axis may be an ideal target for proper NSC proliferation and differentiation.
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Affiliation(s)
- Zhenhua Xu
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China
| | - Qiaozhen Qin
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China
- Faculty of Environmental and Life Sciences, Beijing University of Technology, Beijing, 100124, China
| | - Yan Wang
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China
- Anhui Medical University, Hefei, 230032, Anhui, China
| | - Heyang Zhang
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China
| | - Shuirong Liu
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China
| | - Xiaotong Li
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China
| | - Yue Chen
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China
| | - Yuqing Wang
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China
| | - Huaqiang Ruan
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China
| | - Wenyan He
- China National Clinical Research Center for Neurological Diseases, Jing-Jin Center for Neuroinflammation, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Tao Zhang
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China
| | - Xinlong Yan
- Faculty of Environmental and Life Sciences, Beijing University of Technology, Beijing, 100124, China
| | - Changyong Wang
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China.
| | - Donggang Xu
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China.
| | - Xiaoxia Jiang
- Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Haidian District, Beijing, 100850, China.
- Anhui Medical University, Hefei, 230032, Anhui, China.
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4
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Spano D, Catara G. Targeting the Ubiquitin-Proteasome System and Recent Advances in Cancer Therapy. Cells 2023; 13:29. [PMID: 38201233 PMCID: PMC10778545 DOI: 10.3390/cells13010029] [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: 11/13/2023] [Revised: 12/12/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
Ubiquitination is a reversible post-translational modification based on the chemical addition of ubiquitin to proteins with regulatory effects on various signaling pathways. Ubiquitination can alter the molecular functions of tagged substrates with respect to protein turnover, biological activity, subcellular localization or protein-protein interaction. As a result, a wide variety of cellular processes are under ubiquitination-mediated control, contributing to the maintenance of cellular homeostasis. It follows that the dysregulation of ubiquitination reactions plays a relevant role in the pathogenic states of human diseases such as neurodegenerative diseases, immune-related pathologies and cancer. In recent decades, the enzymes of the ubiquitin-proteasome system (UPS), including E3 ubiquitin ligases and deubiquitinases (DUBs), have attracted attention as novel druggable targets for the development of new anticancer therapeutic approaches. This perspective article summarizes the peculiarities shared by the enzymes involved in the ubiquitination reaction which, when deregulated, can lead to tumorigenesis. Accordingly, an overview of the main pharmacological interventions based on targeting the UPS that are in clinical use or still in clinical trials is provided, also highlighting the limitations of the therapeutic efficacy of these approaches. Therefore, various attempts to circumvent drug resistance and side effects as well as UPS-related emerging technologies in anticancer therapeutics are discussed.
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Affiliation(s)
- Daniela Spano
- Institute for Endocrinology and Experimental Oncology “G. Salvatore”, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Giuliana Catara
- Institute of Biochemistry and Cell Biology, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
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5
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Hanot M, Raby L, Völkel P, Le Bourhis X, Angrand PO. The Contribution of the Zebrafish Model to the Understanding of Polycomb Repression in Vertebrates. Int J Mol Sci 2023; 24:ijms24032322. [PMID: 36768643 PMCID: PMC9916924 DOI: 10.3390/ijms24032322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/20/2023] [Accepted: 01/21/2023] [Indexed: 01/26/2023] Open
Abstract
Polycomb group (PcG) proteins are highly conserved proteins assembled into two major types of complexes, PRC1 and PRC2, involved in the epigenetic silencing of a wide range of gene expression programs regulating cell fate and tissue development. The crucial role of PRC1 and PRC2 in the fundamental cellular processes and their involvement in human pathologies such as cancer attracted intense attention over the last few decades. Here, we review recent advancements regarding PRC1 and PRC2 function using the zebrafish model. We point out that the unique characteristics of the zebrafish model provide an exceptional opportunity to increase our knowledge of the role of the PRC1 and PRC2 complexes in tissue development, in the maintenance of organ integrity and in pathology.
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Affiliation(s)
- Mariette Hanot
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Ludivine Raby
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Pamela Völkel
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Xuefen Le Bourhis
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Pierre-Olivier Angrand
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
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6
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Akita N, Okada R, Mukae K, Sugino RP, Takenobu H, Chikaraishi K, Ochiai H, Yamaguchi Y, Ohira M, Koseki H, Kamijo T. Polycomb group protein BMI1 protects neuroblastoma cells against DNA damage-induced apoptotic cell death. Exp Cell Res 2023; 422:113412. [PMID: 36370852 DOI: 10.1016/j.yexcr.2022.113412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 10/31/2022] [Accepted: 11/05/2022] [Indexed: 11/10/2022]
Abstract
The overexpression of BMI1, a polycomb protein, correlates with cancer development and aggressiveness. We previously reported that MYCN-induced BMI1 positively regulated neuroblastoma (NB) cell proliferation via the transcriptional inhibition of tumor suppressors in NB cells. To assess the potential of BMI1 as a new target for NB therapy, we examined the effects of reductions in BMI1 on NB cells. BMI1 knockdown (KD) in NB cells significantly induced their differentiation for up to 7 days. BMI1 depletion significantly induced apoptotic NB cell death for up to 14 days along with the activation of p53, increases in p73, and induction of p53 family downstream molecules and pathways, even in p53 mutant cells. BMI1 depletion in vivo markedly suppressed NB xenograft tumor growth. BMI1 reductions activated ATM and increased γ-H2AX in NB cells. These DNA damage signals and apoptotic cell death were not canceled by the transduction of the polycomb group molecules EZH2 and RING1B. Furthermore, EZH2 and RING1B KD did not induce apoptotic NB cell death to the same extent as BMI1 KD. Collectively, these results suggest the potential of BMI1 as a target of molecular therapy for NB and confirmed, for the first time, the shared role of PcG proteins in the DNA damage response of NB cells.
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Affiliation(s)
- Nobuhiro Akita
- Department of Hematology and Oncology, Children's Medical Center, Japanese Red Cross Aichi Medical Center Nagoya First Hospital, Japan; Division of Biochemistry and Molecular Carcinogenesis, Chiba Cancer Center Research Institute, Japan; Department of Pediatrics, Chiba University School of Medicine, Japan; Research Institute for Clinical Oncology, Saitama Cancer Center, Japan
| | - Ryu Okada
- Research Institute for Clinical Oncology, Saitama Cancer Center, Japan; Department of Graduate School of Science and Engineering, Saitama University, Japan
| | - Kyosuke Mukae
- Research Institute for Clinical Oncology, Saitama Cancer Center, Japan
| | - Ryuichi P Sugino
- Research Institute for Clinical Oncology, Saitama Cancer Center, Japan
| | - Hisanori Takenobu
- Division of Biochemistry and Molecular Carcinogenesis, Chiba Cancer Center Research Institute, Japan; Research Institute for Clinical Oncology, Saitama Cancer Center, Japan.
| | - Koji Chikaraishi
- Department of Pediatrics, Chiba University School of Medicine, Japan; Research Institute for Clinical Oncology, Saitama Cancer Center, Japan
| | - Hidemasa Ochiai
- Department of Pediatrics, Chiba University School of Medicine, Japan
| | - Yohko Yamaguchi
- Division of Biochemistry and Molecular Carcinogenesis, Chiba Cancer Center Research Institute, Japan; Department of Molecular Toxicology, Faculty of Pharmaceutical Sciences, Toho University, Japan
| | - Miki Ohira
- Division of Biochemistry and Molecular Carcinogenesis, Chiba Cancer Center Research Institute, Japan; Research Institute for Clinical Oncology, Saitama Cancer Center, Japan
| | - Haruhiko Koseki
- Developmental Genetics Group, RIKEN Research Center for Allergy and Immunology, Japan
| | - Takehiko Kamijo
- Division of Biochemistry and Molecular Carcinogenesis, Chiba Cancer Center Research Institute, Japan; Research Institute for Clinical Oncology, Saitama Cancer Center, Japan; Department of Graduate School of Science and Engineering, Saitama University, Japan.
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7
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Medina EA, Delma CR, Yang FC. ASXL1/2 mutations and myeloid malignancies. J Hematol Oncol 2022; 15:127. [PMID: 36068610 PMCID: PMC9450349 DOI: 10.1186/s13045-022-01336-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 08/04/2022] [Indexed: 11/10/2022] Open
Abstract
Myeloid malignancies develop through the accumulation of genetic and epigenetic alterations that dysregulate hematopoietic stem cell (HSC) self-renewal, stimulate HSC proliferation and result in differentiation defects. The polycomb group (PcG) and trithorax group (TrxG) of epigenetic regulators act antagonistically to regulate the expression of genes key to stem cell functions. The genes encoding these proteins, and the proteins that interact with them or affect their occupancy at chromatin, are frequently mutated in myeloid malignancies. PcG and TrxG proteins are regulated by Enhancers of Trithorax and Polycomb (ETP) proteins. ASXL1 and ASXL2 are ETP proteins that assemble chromatin modification complexes and transcription factors. ASXL1 mutations frequently occur in myeloid malignancies and are associated with a poor prognosis, whereas ASXL2 mutations frequently occur in AML with t(8;21)/RUNX1-RUNX1T1 and less frequently in other subtypes of myeloid malignancies. Herein, we review the role of ASXL1 and ASXL2 in normal and malignant hematopoiesis by summarizing the findings of mouse model systems and discussing their underlying molecular mechanisms.
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Affiliation(s)
- Edward A Medina
- Division of Hematopathology, Department of Pathology and Laboratory Medicine, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229-3900, USA.
| | - Caroline R Delma
- Division of Hematopathology, Department of Pathology and Laboratory Medicine, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229-3900, USA
| | - Feng-Chun Yang
- Department of Cell Systems and Anatomy, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, 78229, USA.,Mays Cancer Center, University of Texas Health San Antonio, San Antonio, TX, 78229, USA
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8
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Angrand PO. Structure and Function of the Polycomb Repressive Complexes PRC1 and PRC2. Int J Mol Sci 2022; 23:ijms23115971. [PMID: 35682651 PMCID: PMC9181254 DOI: 10.3390/ijms23115971] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 05/13/2022] [Indexed: 12/20/2022] Open
Affiliation(s)
- Pierre-Olivier Angrand
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR 9020-U 1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
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9
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Owen BM, Davidovich C. DNA binding by polycomb-group proteins: searching for the link to CpG islands. Nucleic Acids Res 2022; 50:4813-4839. [PMID: 35489059 PMCID: PMC9122586 DOI: 10.1093/nar/gkac290] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/25/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Polycomb group proteins predominantly exist in polycomb repressive complexes (PRCs) that cooperate to maintain the repressed state of thousands of cell-type-specific genes. Targeting PRCs to the correct sites in chromatin is essential for their function. However, the mechanisms by which PRCs are recruited to their target genes in mammals are multifactorial and complex. Here we review DNA binding by polycomb group proteins. There is strong evidence that the DNA-binding subunits of PRCs and their DNA-binding activities are required for chromatin binding and CpG targeting in cells. In vitro, CpG-specific binding was observed for truncated proteins externally to the context of their PRCs. Yet, the mere DNA sequence cannot fully explain the subset of CpG islands that are targeted by PRCs in any given cell type. At this time we find very little structural and biophysical evidence to support a model where sequence-specific DNA-binding activity is required or sufficient for the targeting of CpG-dinucleotide sequences by polycomb group proteins while they are within the context of their respective PRCs, either PRC1 or PRC2. We discuss the current knowledge and open questions on how the DNA-binding activities of polycomb group proteins facilitate the targeting of PRCs to chromatin.
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Affiliation(s)
- Brady M Owen
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia
| | - Chen Davidovich
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia.,EMBL-Australia, Clayton, VIC, Australia
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10
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Vijayanathan M, Trejo-Arellano MG, Mozgová I. Polycomb Repressive Complex 2 in Eukaryotes-An Evolutionary Perspective. EPIGENOMES 2022; 6:3. [PMID: 35076495 PMCID: PMC8788455 DOI: 10.3390/epigenomes6010003] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 01/12/2022] [Accepted: 01/12/2022] [Indexed: 12/23/2022] Open
Abstract
Polycomb repressive complex 2 (PRC2) represents a group of evolutionarily conserved multi-subunit complexes that repress gene transcription by introducing trimethylation of lysine 27 on histone 3 (H3K27me3). PRC2 activity is of key importance for cell identity specification and developmental phase transitions in animals and plants. The composition, biochemistry, and developmental function of PRC2 in animal and flowering plant model species are relatively well described. Recent evidence demonstrates the presence of PRC2 complexes in various eukaryotic supergroups, suggesting conservation of the complex and its function. Here, we provide an overview of the current understanding of PRC2-mediated repression in different representatives of eukaryotic supergroups with a focus on the green lineage. By comparison of PRC2 in different eukaryotes, we highlight the possible common and diverged features suggesting evolutionary implications and outline emerging questions and directions for future research of polycomb repression and its evolution.
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Affiliation(s)
- Mallika Vijayanathan
- Biology Centre, Institute of Plant Molecular Biology, Czech Academy of Sciences, 370 05 Ceske Budejovice, Czech Republic; (M.V.); (M.G.T.-A.)
| | - María Guadalupe Trejo-Arellano
- Biology Centre, Institute of Plant Molecular Biology, Czech Academy of Sciences, 370 05 Ceske Budejovice, Czech Republic; (M.V.); (M.G.T.-A.)
| | - Iva Mozgová
- Biology Centre, Institute of Plant Molecular Biology, Czech Academy of Sciences, 370 05 Ceske Budejovice, Czech Republic; (M.V.); (M.G.T.-A.)
- Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic
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11
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Oncogenic Truncations of ASXL1 Enhance a Motif for BRD4 ET-Domain Binding. J Mol Biol 2021; 433:167242. [PMID: 34536441 DOI: 10.1016/j.jmb.2021.167242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 09/04/2021] [Accepted: 09/07/2021] [Indexed: 11/23/2022]
Abstract
Proper regulation of gene-expression relies on specific protein-protein interactions between a myriad of epigenetic regulators. As such, mutation of genes encoding epigenetic regulators often drive cancer and developmental disorders. Additional sex combs-like protein 1 (ASXL1) is a key example, where mutations frequently drive haematological cancers and can cause developmental disorders. It has been reported that nonsense mutations in ASXL1 promote an interaction with BRD4, another central epigenetic regulator. Here we provide a molecular mechanism for the BRD4-ASXL1 interaction, demonstrating that a motif near to common truncation breakpoints of ASXL1 contains an epitope that binds the ET domain within BRD4. Binding-studies show that this interaction is analogous to common ET-binding modes of BRD4-interactors, and that all three ASX-like protein orthologs (ASXL1-3) contain a functional ET domain-binding epitope. Crucially, we observe that BRD4-ASXL1 binding is markedly increased in the prevalent ASXL1Y591X truncation that maintains the BRD4-binding epitope, relative to full-length ASXL1 or truncated proteins that delete the epitope. Together, these results show that ASXL1 truncation enhances BRD4 recruitment to transcriptional complexes via its ET domain, which could misdirect regulatory activity of either BRD4 or ASXL1 and may inform potential therapeutic interventions.
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