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Chen X, Wang K, Mufti FUD, Xu D, Zhu C, Huang X, Zeng C, Jin Q, Huang X, Yan YH, Dong MQ, Feng X, Shi Y, Kennedy S, Guang S. Germ granule compartments coordinate specialized small RNA production. Nat Commun 2024; 15:5799. [PMID: 38987544 PMCID: PMC11236994 DOI: 10.1038/s41467-024-50027-3] [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: 12/11/2023] [Accepted: 06/26/2024] [Indexed: 07/12/2024] Open
Abstract
Germ granules are biomolecular condensates present in most animal germ cells. One function of germ granules is to help maintain germ cell totipotency by organizing mRNA regulatory machinery, including small RNA-based gene regulatory pathways. The C. elegans germ granule is compartmentalized into multiple subcompartments whose biological functions are largely unknown. Here, we identify an uncharted subcompartment of the C. elegans germ granule, which we term the E granule. The E granule is nonrandomly positioned within the germ granule. We identify five proteins that localize to the E granule, including the RNA-dependent RNA polymerase (RdRP) EGO-1, the Dicer-related helicase DRH-3, the Tudor domain-containing protein EKL-1, and two intrinsically disordered proteins, EGC-1 and ELLI-1. Localization of EGO-1 to the E granule enables synthesis of a specialized class of 22G RNAs, which derive exclusively from 5' regions of a subset of germline-expressed mRNAs. Defects in E granule assembly elicit disordered production of endogenous siRNAs, which disturbs fertility and the RNAi response. Our results define a distinct subcompartment of the C. elegans germ granule and suggest that one function of germ granule compartmentalization is to facilitate the localized production of specialized classes of small regulatory RNAs.
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Affiliation(s)
- Xiangyang Chen
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Ke Wang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Farees Ud Din Mufti
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Demin Xu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Chengming Zhu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Xinya Huang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Chenming Zeng
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Qile Jin
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Xiaona Huang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Yong-Hong Yan
- National Institute of Biological Sciences, Beijing, 102206, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing, 102206, China
| | - Xuezhu Feng
- School of Basic Medicine, Anhui Medical University, Hefei, China.
| | - Yunyu Shi
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China.
| | - Scott Kennedy
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, MA, 02115, USA.
| | - Shouhong Guang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, 230027, China.
- CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Hefei, Anhui, 230027, China.
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Gajjar G, Huggins HP, Kim ES, Huang W, Bonnet FX, Updike DL, Keiper BD. Two germ granule eIF4E isoforms reside in different mRNPs to hand off C elegans mRNAs from translational repression to activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.24.595216. [PMID: 38826235 PMCID: PMC11142241 DOI: 10.1101/2024.05.24.595216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
We studied the function of translation factor eIF4E isoforms in regulating mRNAs in germ cell granules/condensates. Translational control of mRNAs plays an essential role in germ cell gene regulation. Messenger ribonucleoprotein (mRNP) complexes assemble on mRNAs as they move from the nucleus into perinuclear germ granules to exert both positive and negative post-transcriptional regulation in the cytoplasm. In C. elegans , germ granules are surprisingly dynamic mRNP condensates that remodel during development. Two eIF4E isoforms (called IFE-1 and IFE-3), eIF4E-Interacting Proteins (4EIPs), RBPs, DEAD-box helicases, polyadenylated mRNAs, Argonautes and miRNAs all occupy positions in germ granules. Affinity purification of IFE-1 and IFE-3 allowed mass spectrometry and mRNA-Seq to identify the proteins and mRNAs that populate stable eIF4E mRNPs. We find translationally controlled mRNAs (e.g. pos-1, mex-3, spn-4, etc.) enriched in IFE-3 mRNPs, but excluded from IFE-1 mRNPs. These mRNAs also require IFE-1 for efficient translation. The findings support a model in which oocytes and embryos utilize the two eIF4Es for opposite purposes on critically regulated germline mRNAs. Careful colocalization of the eIF4Es with other germ granule components suggests an architecture in which GLH-1, PGL-1 and the IFEs are stratified to facilitate sequential interactions for mRNAs. Biochemical characterization demonstrates opposing yet cooperative roles for IFE-3 and IFE-1 to hand-off of translationally controlled mRNAs from the repressed to the activated state, respectively. The model involves eIF4E mRNPs shuttling mRNAs through nuclear pore-associated granules/condensates to cytoplasmic ribosomes.
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Brown HE, Varderesian HV, Keane SA, Ryder SP. The mex-3 3' untranslated region is essential for reproduction during temperature stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.01.587367. [PMID: 38798418 PMCID: PMC11123400 DOI: 10.1101/2024.04.01.587367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Organisms must sense temperature and modify their physiology to ensure survival during environmental stress. Elevated temperature leads to reduced fertility in most sexually reproducing organisms. Maternally supplied mRNAs are required for embryogenesis. They encode proteins that govern early events in embryonic patterning. RNA-binding proteins (RBPs) are major effectors of maternal mRNA regulation. MEX-3 is a conserved RBP essential for anterior patterning of Caenorhabditis elegans embryos. We previously demonstrated that the mex-3 3' untranslated region (3'UTR) represses MEX-3 abundance in the germline yet is dispensable for fertility. Here, we show that the 3'UTR becomes essential during thermal stress. Deletion of the 3'UTR causes a highly penetrant temperature sensitive embryonic lethality phenotype distinct from a mex-3 null. Loss of the 3'UTR decreases MEX-3 abundance specifically in maturing oocytes and early embryos experiencing temperature stress, suggesting a mechanism that regulates MEX-3 abundance at the oocyte-to-embryo transition is sensitive to temperature. We propose that a primary role of the mex-3 3'UTR is to buffer MEX-3 expression to ensure viability during fluctuating temperature. We hypothesize that a major role of maternally supplied mRNAs is to ensure robust expression of key cell fate determinants in uncertain conditions.
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Liu J, Murray JI. Mechanisms of lineage specification in Caenorhabditis elegans. Genetics 2023; 225:iyad174. [PMID: 37847877 DOI: 10.1093/genetics/iyad174] [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: 08/26/2023] [Accepted: 09/18/2023] [Indexed: 10/19/2023] Open
Abstract
The studies of cell fate and lineage specification are fundamental to our understanding of the development of multicellular organisms. Caenorhabditis elegans has been one of the premiere systems for studying cell fate specification mechanisms at single cell resolution, due to its transparent nature, the invariant cell lineage, and fixed number of somatic cells. We discuss the general themes and regulatory mechanisms that have emerged from these studies, with a focus on somatic lineages and cell fates. We next review the key factors and pathways that regulate the specification of discrete cells and lineages during embryogenesis and postembryonic development; we focus on transcription factors and include numerous lineage diagrams that depict the expression of key factors that specify embryonic founder cells and postembryonic blast cells, and the diverse somatic cell fates they generate. We end by discussing some future perspectives in cell and lineage specification.
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Affiliation(s)
- Jun Liu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - John Isaac Murray
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Chen W, Hu L, Lu X, Wang X, Zhao C, Guo C, Li X, Ding Y, Zhao H, Tong D, Wang L, Huang C. The RNA binding protein MEX3A promotes tumor progression of breast cancer by post-transcriptional regulation of IGFBP4. Breast Cancer Res Treat 2023; 201:353-366. [PMID: 37433992 PMCID: PMC10460732 DOI: 10.1007/s10549-023-07028-5] [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: 02/17/2023] [Accepted: 06/27/2023] [Indexed: 07/13/2023]
Abstract
PURPOSE Breast cancer (BC) is the most frequent malignant tumor in women worldwide with exceptionally high morbidity. The RNA-binding protein MEX3A plays a crucial role in genesis and progression of multiple cancers. We attempted to explore its clinicopathological and functional significance in BC in which MEX3A is expressed. METHODS The expression of MEX3A detected by RT-qPCR and correlated the results with clinicopathological variables in 53 BC patients. MEX3A and IGFBP4 profile data of BC patients were downloaded from TCGA and GEO database. Kaplan-Meier (KM) analysis was used to estimate the survival rate of BC patients. Western Blot, CCK-8, EdU, colony formation and flow cytometry were performed to investigate the role of MEX3A and IGFBP4 in BC cell proliferation, invasion and cell cycle in vitro. A subcutaneous tumor mouse model was constructed to analyze in vivo growth of BC cells after MEX3A knockdown. The interactions among MEX3A and IGFBP4 were measured by RNA pull-down and RNA immunoprecipitation. RESULTS The expression of MEX3A was upregulated in BC tissues compared to adjacent tissues and high expression of MEX3A was associated with poor prognosis. Subsequent in vitro studies demonstrated that MEX3A knockdown inhibited BC cells proliferation and migration, as well as xenograft tumor growth in vivo. The expression of IGFBP4 was significantly negatively correlated with MEX3A in BC tissues. Mechanistic investigation showed that MEX3A binds to IGFBP4 mRNA in BC cells, decreasing IGFBP4 mRNA levels, which further activated the PI3K/AKT and other downstream signaling pathways implicated cell cycle progression and cell migration. CONCLUSION Our results indicate that MEX3A plays a prominent oncogenic role in BC tumorigenesis and progression by targeting IGFBP4 mRNA and activating PI3K/AKT signaling, which can be used as a novel therapeutic target for BC.
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Affiliation(s)
- Wenhu Chen
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shanxi, China
- School of Basic Medical Sciences & Forensic Medicine, Hangzhou Medical College, Hangzhou, 310053, China
| | - Liqiang Hu
- Cancer Institute of Integrated Traditional Chinese and Western Medicine, Zhejiang Academy of Traditional Chinese Medicine, Hangzhou, 310012, China
| | - Xuemei Lu
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Xiaofei Wang
- Biomedical Experimental Center of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Changan Zhao
- Department of Pathology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Chen Guo
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shanxi, China
| | - Xiaoyan Li
- School of Basic Medical Sciences & Forensic Medicine, Hangzhou Medical College, Hangzhou, 310053, China
| | - Yuqin Ding
- Department of Breast Surgery, Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Hangzhou, 310005, China
| | - Hongguang Zhao
- Department of Thoracic Surgery, Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Hangzhou, 310005, China
| | - Dongdong Tong
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shanxi, China
- Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Lifang Wang
- College of Innovation & Entrepreneurship, Hangzhou Medical College, No. 548 Binwen Road, Hangzhou, 310053, Zhejiang, China.
| | - Chen Huang
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shanxi, China.
- Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China.
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, 710061, China.
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Domingo-Muelas A, Duart-Abadia P, Morante-Redolat JM, Jordán-Pla A, Belenguer G, Fabra-Beser J, Paniagua-Herranz L, Pérez-Villalba A, Álvarez-Varela A, Barriga FM, Gil-Sanz C, Ortega F, Batlle E, Fariñas I. Post-transcriptional control of a stemness signature by RNA-binding protein MEX3A regulates murine adult neurogenesis. Nat Commun 2023; 14:373. [PMID: 36690670 PMCID: PMC9871011 DOI: 10.1038/s41467-023-36054-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 01/12/2023] [Indexed: 01/25/2023] Open
Abstract
Neural stem cells (NSCs) in the adult murine subependymal zone balance their self-renewal capacity and glial identity with the potential to generate neurons during the lifetime. Adult NSCs exhibit lineage priming via pro-neurogenic fate determinants. However, the protein levels of the neural fate determinants are not sufficient to drive direct differentiation of adult NSCs, which raises the question of how cells along the neurogenic lineage avoid different conflicting fate choices, such as self-renewal and differentiation. Here, we identify RNA-binding protein MEX3A as a post-transcriptional regulator of a set of stemness associated transcripts at critical transitions in the subependymal neurogenic lineage. MEX3A regulates a quiescence-related RNA signature in activated NSCs that is needed for their return to quiescence, playing a role in the long-term maintenance of the NSC pool. Furthermore, it is required for the repression of the same program at the onset of neuronal differentiation. Our data indicate that MEX3A is a pivotal regulator of adult murine neurogenesis acting as a translational remodeller.
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Grants
- EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 European Research Council (H2020 Excellent Science - European Research Council)
- Ministerio de Ciencia e Innovación (MICINN, Spain) - PID2020-119917RB-I00.
- Regional Government of Valencia | Conselleria d'Educació, Investigació, Cultura i Esport (Conselleria d'Educació, Investigació, Cultura i Esport de la Generalitat Valenciana)
- Ministerio de Ciencia e Innovación (MICINN, Spain) - PID2020-117937GB-I00, PID2020-119917RB-I00, PID 2019-109155RB-I00, PID2020-114227RB-I00, RyC-2015-19058, PRE2018-084838. Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED, Spain) - MICINN- CB06/05/0086.
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Affiliation(s)
- Ana Domingo-Muelas
- Departamento de Biología Celular, Biología Funcional y Antropología Física, Universidad de Valencia, Valencia, Spain
- Instituto de Biotecnología y Biomedicina (BIOTECMED), Universidad de Valencia, Valencia, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Valencia, Spain
| | - Pere Duart-Abadia
- Departamento de Biología Celular, Biología Funcional y Antropología Física, Universidad de Valencia, Valencia, Spain
- Instituto de Biotecnología y Biomedicina (BIOTECMED), Universidad de Valencia, Valencia, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Valencia, Spain
| | - Jose Manuel Morante-Redolat
- Departamento de Biología Celular, Biología Funcional y Antropología Física, Universidad de Valencia, Valencia, Spain
- Instituto de Biotecnología y Biomedicina (BIOTECMED), Universidad de Valencia, Valencia, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Valencia, Spain
| | - Antonio Jordán-Pla
- Instituto de Biotecnología y Biomedicina (BIOTECMED), Universidad de Valencia, Valencia, Spain
| | - Germán Belenguer
- Departamento de Biología Celular, Biología Funcional y Antropología Física, Universidad de Valencia, Valencia, Spain
- Instituto de Biotecnología y Biomedicina (BIOTECMED), Universidad de Valencia, Valencia, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Valencia, Spain
| | - Jaime Fabra-Beser
- Departamento de Biología Celular, Biología Funcional y Antropología Física, Universidad de Valencia, Valencia, Spain
- Instituto de Biotecnología y Biomedicina (BIOTECMED), Universidad de Valencia, Valencia, Spain
| | - Lucía Paniagua-Herranz
- Departamento de Bioquímica y Biología Molecular, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Madrid, Spain
- Instituto de Investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
| | - Ana Pérez-Villalba
- Departamento de Biología Celular, Biología Funcional y Antropología Física, Universidad de Valencia, Valencia, Spain
- Instituto de Biotecnología y Biomedicina (BIOTECMED), Universidad de Valencia, Valencia, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Valencia, Spain
| | - Adrián Álvarez-Varela
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Barcelona, Spain
| | - Francisco M Barriga
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Barcelona, Spain
| | - Cristina Gil-Sanz
- Departamento de Biología Celular, Biología Funcional y Antropología Física, Universidad de Valencia, Valencia, Spain
- Instituto de Biotecnología y Biomedicina (BIOTECMED), Universidad de Valencia, Valencia, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Valencia, Spain
| | - Felipe Ortega
- Departamento de Bioquímica y Biología Molecular, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Madrid, Spain
- Instituto de Investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
| | - Eduard Batlle
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain.
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Barcelona, Spain.
- ICREA, Barcelona, Spain.
| | - Isabel Fariñas
- Departamento de Biología Celular, Biología Funcional y Antropología Física, Universidad de Valencia, Valencia, Spain.
- Instituto de Biotecnología y Biomedicina (BIOTECMED), Universidad de Valencia, Valencia, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Valencia, Spain.
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Albarqi MMY, Ryder SP. The role of RNA-binding proteins in orchestrating germline development in Caenorhabditis elegans. Front Cell Dev Biol 2023; 10:1094295. [PMID: 36684428 PMCID: PMC9846511 DOI: 10.3389/fcell.2022.1094295] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/19/2022] [Indexed: 01/06/2023] Open
Abstract
RNA passed from parents to progeny controls several aspects of early development. The germline of the free-living nematode Caenorhabditis elegans contains many families of evolutionarily conserved RNA-binding proteins (RBPs) that target the untranslated regions of mRNA transcripts to regulate their translation and stability. In this review, we summarize what is known about the binding specificity of C. elegans germline RNA-binding proteins and the mechanisms of mRNA regulation that contribute to their function. We examine the emerging role of miRNAs in translational regulation of germline and embryo development. We also provide an overview of current technology that can be used to address the gaps in our understanding of RBP regulation of mRNAs. Finally, we present a hypothetical model wherein multiple 3'UTR-mediated regulatory processes contribute to pattern formation in the germline to ensure the proper and timely localization of germline proteins and thus a functional reproductive system.
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Elaswad MT, Munderloh C, Watkins BM, Sharp KG, Breton E, Schisa JA. Imaging-associated stress causes divergent phase transitions of RNA-binding proteins in the Caenorhabditis elegans germ line. G3 GENES|GENOMES|GENETICS 2022; 12:6633935. [PMID: 35801939 PMCID: PMC9434235 DOI: 10.1093/g3journal/jkac172] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 06/29/2022] [Indexed: 11/25/2022]
Abstract
One emerging paradigm of cellular organization of RNA and RNA-binding proteins is the formation of membraneless organelles. Examples of membraneless organelles include several types of ribonucleoprotein granules that form via phase separation. A variety of intracellular pH changes and posttranslational modifications, as well as extracellular stresses, can stimulate the condensation of proteins into granules. For example, the assembly of stress granules induced by oxidative stress, osmotic stress, and heat stress has been well characterized in a variety of somatic cell types. In the germ line, similar stress-induced condensation of proteins occurs; however, less is known about the role of phase separation during gamete production. Researchers who study phase transitions often make use of fluorescent reporters to study the dynamics of RNA-binding proteins during live cell imaging. In this report, we demonstrate that common conditions of live-imaging Caenorhabditis elegans can cause an inadvertent stress and trigger phase transitions of RNA-binding proteins. We show that this imaging-associated stress stimulates decondensation of multiple germ granule proteins and condensation of several P-body proteins. Proteins within larger ribonucleoprotein granules in meiotically arrested oocytes do not appear to be as sensitive to the stress as proteins in diakinesis oocytes of young hermaphrodites, with the exception of the germ granule protein PGL-1. Our results have important methodological implications for all researchers using live-cell imaging techniques. The data also suggest that the RNA-binding proteins within large ribonucleoprotein granules of arrested oocytes may have distinct phases, which we characterize in our companion article.
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Affiliation(s)
- Mohamed T Elaswad
- Biochemistry, Cell and Molecular Biology Program, Central Michigan University , Mt. Pleasant, MI 48859, USA
- Department of Biology, Central Michigan University , Mt. Pleasant, MI 48859, USA
| | - Chloe Munderloh
- Department of Biology, Central Michigan University , Mt. Pleasant, MI 48859, USA
- Present address Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brooklynne M Watkins
- Biochemistry, Cell and Molecular Biology Program, Central Michigan University , Mt. Pleasant, MI 48859, USA
- Department of Biology, Central Michigan University , Mt. Pleasant, MI 48859, USA
| | - Katherine G Sharp
- Department of Biology, Central Michigan University , Mt. Pleasant, MI 48859, USA
- Present address Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Elizabeth Breton
- Department of Biology, Central Michigan University , Mt. Pleasant, MI 48859, USA
- Present address Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Jennifer A Schisa
- Biochemistry, Cell and Molecular Biology Program, Central Michigan University , Mt. Pleasant, MI 48859, USA
- Department of Biology, Central Michigan University , Mt. Pleasant, MI 48859, USA
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Phillips CM, Updike DL. Germ granules and gene regulation in the Caenorhabditis elegans germline. Genetics 2022; 220:6541922. [PMID: 35239965 PMCID: PMC8893257 DOI: 10.1093/genetics/iyab195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/10/2021] [Indexed: 01/27/2023] Open
Abstract
The transparency of Caenorhabditis elegans provides a unique window to observe and study the function of germ granules. Germ granules are specialized ribonucleoprotein (RNP) assemblies specific to the germline cytoplasm, and they are largely conserved across Metazoa. Within the germline cytoplasm, they are positioned to regulate mRNA abundance, translation, small RNA production, and cytoplasmic inheritance to help specify and maintain germline identity across generations. Here we provide an overview of germ granules and focus on the significance of more recent observations that describe how they further demix into sub-granules, each with unique compositions and functions.
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Affiliation(s)
- Carolyn M Phillips
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA,Corresponding author: (C.M.P.); (D.L.U.)
| | - Dustin L Updike
- The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA,Corresponding author: (C.M.P.); (D.L.U.)
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10
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RNA-binding protein MEX3A controls G1/S transition via regulating the RB/E2F pathway in clear cell renal cell carcinoma. MOLECULAR THERAPY - NUCLEIC ACIDS 2022; 27:241-255. [PMID: 34976441 PMCID: PMC8703191 DOI: 10.1016/j.omtn.2021.11.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 11/29/2021] [Indexed: 11/24/2022]
Abstract
MEX3A is an RNA-binding protein that mediates mRNA decay through binding to 3′ untranslated regions. However, its role and mechanism in clear cell renal cell carcinoma remain unknown. In this study, we found that MEX3A expression was transcriptionally activated by ETS1 and upregulated in clear cell renal cell carcinoma. Silencing MEX3A markedly reduced clear cell renal cell carcinoma cell proliferation in vitro and in vivo. Inhibiting MEX3A induced G1/S cell-cycle arrest. Gene set enrichment analysis revealed that E2F targets are the central downstream pathways of MEX3A. To identify MEX3A targets, systematic screening using enhanced cross-linking and immunoprecipitation sequencing, and RNA-immunoprecipitation sequencing assays were performed. A network of 4,000 genes was identified as potential targets of MEX3A. Gene ontology analysis of upregulated genes bound by MEX3A indicated that negative regulation of the cell proliferation pathway was highly enriched. Further assays indicated that MEX3A bound to the CDKN2B 3′ untranslated region, promoting its mRNA degradation. This leads to decreased levels of CDKN2B and an uncontrolled cell cycle in clear cell renal cell carcinoma, which was confirmed by rescue experiments. Our findings revealed that MEX3A acts as a post-transcriptional regulator of abnormal cell-cycle progression in clear cell renal cell carcinoma.
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11
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Salamon I, Rasin MR. Evolution of the Neocortex Through RNA-Binding Proteins and Post-transcriptional Regulation. Front Neurosci 2022; 15:803107. [PMID: 35082597 PMCID: PMC8784817 DOI: 10.3389/fnins.2021.803107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/16/2021] [Indexed: 12/24/2022] Open
Abstract
The human neocortex is undoubtedly considered a supreme accomplishment in mammalian evolution. It features a prenatally established six-layered structure which remains plastic to the myriad of changes throughout an organism’s lifetime. A fundamental feature of neocortical evolution and development is the abundance and diversity of the progenitor cell population and their neuronal and glial progeny. These evolutionary upgrades are partially enabled due to the progenitors’ higher proliferative capacity, compartmentalization of proliferative regions, and specification of neuronal temporal identities. The driving force of these processes may be explained by temporal molecular patterning, by which progenitors have intrinsic capacity to change their competence as neocortical neurogenesis proceeds. Thus, neurogenesis can be conceptualized along two timescales of progenitors’ capacity to (1) self-renew or differentiate into basal progenitors (BPs) or neurons or (2) specify their fate into distinct neuronal and glial subtypes which participate in the formation of six-layers. Neocortical development then proceeds through sequential phases of proliferation, differentiation, neuronal migration, and maturation. Temporal molecular patterning, therefore, relies on the precise regulation of spatiotemporal gene expression. An extensive transcriptional regulatory network is accompanied by post-transcriptional regulation that is frequently mediated by the regulatory interplay between RNA-binding proteins (RBPs). RBPs exhibit important roles in every step of mRNA life cycle in any system, from splicing, polyadenylation, editing, transport, stability, localization, to translation (protein synthesis). Here, we underscore the importance of RBP functions at multiple time-restricted steps of early neurogenesis, starting from the cell fate transition of transcriptionally primed cortical progenitors. A particular emphasis will be placed on RBPs with mostly conserved but also divergent evolutionary functions in neural progenitors across different species. RBPs, when considered in the context of the fascinating process of neocortical development, deserve to be main protagonists in the story of the evolution and development of the neocortex.
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12
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Watkins B, Schisa JA. Phase separation dynamics of the C. elegans PGL-1 P granule protein in oocytes are sensitive to heat stress. MICROPUBLICATION BIOLOGY 2021; 2021. [PMID: 34585104 PMCID: PMC8463931 DOI: 10.17912/micropub.biology.000476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/14/2021] [Accepted: 09/21/2021] [Indexed: 12/03/2022]
Abstract
Phase separation has emerged as a widespread process of organizing the cytoplasm of diverse eukaryotic cells. In C. elegans oocytes, several RNA binding proteins are condensed into germ granules called P granules. Prior studies studying the phase transitions of RNA binding proteins in response to increased temperature have suggested that PGL-1 decondenses in oocytes in response to heat. Here, we confirm this finding with a new reporter strain and demonstrate the sensitivity of PGL-1 to temperature changes.
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13
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Chipman AD. The evolution of the gene regulatory networks patterning the Drosophila Blastoderm. Curr Top Dev Biol 2021; 139:297-324. [PMID: 32450964 DOI: 10.1016/bs.ctdb.2020.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Drosophila blastoderm gene regulatory network is one of the best studied networks in biology. It is composed of a series of tiered sub-networks that act sequentially to generate a primary segmental pattern. Many of these sub-networks have been studied in other arthropods, allowing us to reconstruct how each of them evolved over the transition from the arthropod ancestor to the situation seen in Drosophila today. I trace the evolution of each of these networks, showing how some of them have been modified significantly in Drosophila relative to the ancestral state while others are largely conserved across evolutionary timescales. I compare the putative ancestral arthropod segmentation network with that found in Drosophila and discuss how and why it has been modified throughout evolution, and to what extent this modification is unusual.
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Affiliation(s)
- Ariel D Chipman
- The Department of Ecology, Evolution & Behavior, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel.
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14
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Albarqi MMY, Ryder SP. The endogenous mex-3 3´UTR is required for germline repression and contributes to optimal fecundity in C. elegans. PLoS Genet 2021; 17:e1009775. [PMID: 34424904 PMCID: PMC8412283 DOI: 10.1371/journal.pgen.1009775] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 09/02/2021] [Accepted: 08/11/2021] [Indexed: 11/18/2022] Open
Abstract
RNA regulation is essential to successful reproduction. Messenger RNAs delivered from parent to progeny govern early embryonic development. RNA-binding proteins (RBPs) are the key effectors of this process, regulating the translation and stability of parental transcripts to control cell fate specification events prior to zygotic gene activation. The KH-domain RBP MEX-3 is conserved from nematode to human. It was first discovered in Caenorhabditis elegans, where it is essential for anterior cell fate and embryo viability. Here, we show that loss of the endogenous mex-3 3´UTR disrupts its germline expression pattern. An allelic series of 3´UTR deletion variants identify repressing regions of the UTR and demonstrate that repression is not precisely coupled to reproductive success. We also show that several RBPs regulate mex-3 mRNA through its 3´UTR to define its unique germline spatiotemporal expression pattern. Additionally, we find that both poly(A) tail length control and the translation initiation factor IFE-3 contribute to its expression pattern. Together, our results establish the importance of the mex-3 3´UTR to reproductive health and its expression in the germline. Our results suggest that additional mechanisms control MEX-3 function when 3´UTR regulation is compromised. In sexually reproducing organisms, germ cells undergo meiosis and differentiate to form oocytes or sperm. Coordination of this process requires a gene regulatory program that acts while the genome is undergoing chromatin condensation. As such, RNA regulatory pathways are an important contributor. The germline of the nematode Caenorhabditis elegans is a suitable model system to study germ cell differentiation. Several RNA-binding proteins (RBPs) coordinate each transition in the germline such as the transition from mitosis to meiosis. MEX-3 is a conserved RNA-binding protein found in most animals including humans. In C. elegans, MEX-3 displays a highly restricted pattern of expression. Here, we define the importance of the 3´UTR in regulating MEX-3 expression pattern in vivo and characterize the RNA-binding proteins involved in this regulation. Our results show that deleting various mex-3 3´UTR regions alter the pattern of expression in the germline in various ways. These mutations also reduced—but did not eliminate—reproductive capacity. Finally, we demonstrate that multiple post-transcriptional mechanisms control MEX-3 levels in different domains of the germline. Our data suggest that coordination of MEX-3 activity requires multiple layers of regulation to ensure reproductive robustness.
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Affiliation(s)
- Mennatallah M. Y. Albarqi
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Sean P. Ryder
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
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A 4D single-cell protein atlas of transcription factors delineates spatiotemporal patterning during embryogenesis. Nat Methods 2021; 18:893-902. [PMID: 34312566 DOI: 10.1038/s41592-021-01216-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 06/17/2021] [Indexed: 12/27/2022]
Abstract
Complex biological processes such as embryogenesis require precise coordination of cell differentiation programs across both space and time. Using protein-fusion fluorescent reporters and four-dimensional live imaging, we present a protein expression atlas of transcription factors (TFs) mapped onto developmental cell lineages during Caenorhabditis elegans embryogenesis, at single-cell resolution. This atlas reveals a spatiotemporal combinatorial code of TF expression, and a cascade of lineage-specific, tissue-specific and time-specific TFs that specify developmental states. The atlas uncovers regulators of embryogenesis, including an unexpected role of a skin specifier in neurogenesis and the critical function of an uncharacterized TF in convergent muscle differentiation. At the systems level, the atlas provides an opportunity to model cell state-fate relationships, revealing a lineage-dependent state diversity within functionally related cells and a winding trajectory of developmental state progression. Collectively, this single-cell protein atlas represents a valuable resource for elucidating metazoan embryogenesis at the molecular and systems levels.
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16
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Shi X, Sun Y, Zhang Y, Wang W, Xu J, Guan Y, Ding Y, Yao Y. MEX3A promotes development and progression of breast cancer through regulation of PIK3CA. Exp Cell Res 2021; 404:112580. [PMID: 33811903 DOI: 10.1016/j.yexcr.2021.112580] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/12/2021] [Accepted: 03/24/2021] [Indexed: 12/24/2022]
Abstract
Breast cancer has been identified as the most common malignant tumors among women and the morbidity of breast cancer is still increasing rapidly. MEX3A possesses important functions in the regulation of mRNAs and may be involved in a variety of human diseases including cancer, whose relationship with breast cancer is still not clear. In this study, MEX3A was identified as a potential promotor in breast cancer, whose expression was strongly higher in breast cancer tissues than normal tissues. The in vitro experiments showed that MEX3A is capable of promoting the development of breast cancer through stimulating cell proliferation, inhibiting cell apoptosis, arresting cell cycle and promoting cell migration. The functions of MEX3A were also verified in vivo. Furthermore, a combination of genechip analysis and Ingenuity pathway analysis (IPA) identified PIK3CA as a potential downstream target of MEX3A, knockdown of which executes similar inhibitory effects on breast cancer and could alleviate MEX3A-induced progression of breast cancer. In conclusion, our study unveiled, as the first time, MEX3A as a tumor promotor for breast cancer, whose function was carried out probably through the regulation of PIK3CA.
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Affiliation(s)
- Xianbiao Shi
- Department of General Surgery, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Yulu Sun
- School of Medicine, Southeast University, Nanjing, China
| | - Yin Zhang
- Department of General Surgery, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Wei Wang
- Department of General Surgery, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Jiahan Xu
- Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing, China
| | - Yinan Guan
- School of Medicine, Southeast University, Nanjing, China
| | - Yitao Ding
- Department of General Surgery, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China.
| | - Yongzhong Yao
- Department of General Surgery, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China.
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Lederer M, Müller S, Glaß M, Bley N, Ihling C, Sinz A, Hüttelmaier S. Oncogenic Potential of the Dual-Function Protein MEX3A. BIOLOGY 2021; 10:415. [PMID: 34067172 PMCID: PMC8151450 DOI: 10.3390/biology10050415] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 04/26/2021] [Accepted: 05/05/2021] [Indexed: 12/23/2022]
Abstract
MEX3A belongs to the MEX3 (Muscle EXcess) protein family consisting of four members (MEX3A-D) in humans. Characteristic for MEX3 proteins is their domain structure with 2 HNRNPK homology (KH) domains mediating RNA binding and a C-terminal really interesting new gene (RING) domain that harbors E3 ligase function. In agreement with their domain composition, MEX3 proteins were reported to modulate both RNA fate and protein ubiquitination. MEX3 paralogs exhibit an oncofetal expression pattern, they are severely downregulated postnatally, and re-expression is observed in various malignancies. Enforced expression of MEX3 proteins in various cancers correlates with poor prognosis, emphasizing their oncogenic potential. The latter is supported by MEX3A's impact on proliferation, self-renewal as well as migration of tumor cells in vitro and tumor growth in xenograft studies.
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Affiliation(s)
- Marcell Lederer
- Charles Tanford Protein Center, Faculty of Medicine, Institute of Molecular Medicine, Section for Molecular Cell Biology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120 Halle, Germany; (S.M.).; (M.G.).; (N.B.); (S.H.)
| | - Simon Müller
- Charles Tanford Protein Center, Faculty of Medicine, Institute of Molecular Medicine, Section for Molecular Cell Biology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120 Halle, Germany; (S.M.).; (M.G.).; (N.B.); (S.H.)
| | - Markus Glaß
- Charles Tanford Protein Center, Faculty of Medicine, Institute of Molecular Medicine, Section for Molecular Cell Biology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120 Halle, Germany; (S.M.).; (M.G.).; (N.B.); (S.H.)
| | - Nadine Bley
- Charles Tanford Protein Center, Faculty of Medicine, Institute of Molecular Medicine, Section for Molecular Cell Biology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120 Halle, Germany; (S.M.).; (M.G.).; (N.B.); (S.H.)
| | - Christian Ihling
- Center for Structural Mass Spectrometry, Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany; (C.I.); (A.S.)
| | - Andrea Sinz
- Center for Structural Mass Spectrometry, Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany; (C.I.); (A.S.)
| | - Stefan Hüttelmaier
- Charles Tanford Protein Center, Faculty of Medicine, Institute of Molecular Medicine, Section for Molecular Cell Biology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120 Halle, Germany; (S.M.).; (M.G.).; (N.B.); (S.H.)
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18
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The effects of MEX3A knockdown on proliferation, apoptosis and migration of osteosarcoma cells. Cancer Cell Int 2021; 21:197. [PMID: 33827584 PMCID: PMC8028067 DOI: 10.1186/s12935-021-01882-3] [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: 09/04/2020] [Accepted: 03/16/2021] [Indexed: 12/21/2022] Open
Abstract
Background Osteosarcoma is an aggressive malignant tumor which has attracted worldwide attention. MEX3A may be associated with tumors while has not yet seen its coverage on osteosarcoma. Herein, this study was to investigate the correlation between MEX3A and the progression of osteosarcoma. Methods Firstly, we determined that expression of MEX3A was significantly higher in osteosarcoma tissues than that in marginal bone by immunohistochemical staining. Additionally, MEX3A expression was downregulated by the RNAi‐mediated knockdown. The functions of MEX3A knockdown on proliferation, apoptosis, cell cycle, migration was assessed by MTT assay, flow cytometry, wound-healing assay and Transwell assay, respectively. Knockdown of MEX3A resulted in suppressing cell proliferation, increasing cell apoptosis, inducing the G2 phase cell cycle arrest, and attenuating cellular migration. Furthermore, mouse xenograft model confirmed inhibitory effects of MEX3A knockdown on osteosarcoma formation. Results The preliminary exploration on the molecular mechanism of MEX3A in osteosarcoma cells showed that the induction of apoptosis needs the participation of a series of apoptosis- associated factors, such as upregulation of Caspase 3, Caspase 8 and HSP60, downregulation of HSP27 and XIAP. Conclusions In summary, these findings predicated that therapy directed at decreasing MEX3A expression is a potential osteosarcoma treatment. Supplementary Information The online version contains supplementary material available at 10.1186/s12935-021-01882-3.
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Liu YF, Sun XY, Zhang JK, Wang ZH, Ren ZG, Li J, Guo WZ, Zhang SJ. hMex-3A is associated with poor prognosis and contributes to the progression of hepatocellular carcinoma. Hepatobiliary Pancreat Dis Int 2021; 20:147-153. [PMID: 32291179 DOI: 10.1016/j.hbpd.2020.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 03/10/2020] [Indexed: 02/05/2023]
Abstract
BACKGROUND HMex-3A, an RNA-binding protein, was found to be associated with tumorigenesis. However, the roles of hMex-3A in hepatocellular carcinoma (HCC) progression remained unclear. METHODS The different expression of hMex-3A between HCC tissues and non-tumor tissues was evaluated using The Cancer Genome Atlas database. Thereafter, the hMex-3A expression was evaluated in HCC tissues using Western blotting and qRT-PCR. Immunohistochemistry was performed to investigate the association between hMex-3A level and clinicopathological features including prognosis in HCC patients. In addition, we used si-hMex-3A to knockdown hMex-3A in HCC cells to test Cell Counting Kit-8, colony formation, cell migration and invasion. RESULTS The hMex-3A expression was significantly elevated in HCC tissues. Analysis of the clinicopathological parameters suggested that hMex-3A expression was significantly associated with pathological grade (P = 0.019) and TNM stage (P = 0.001) in HCC. Moreover, univariate and multivariate Cox-regression analyses revealed that high hMex-3A expression (HR = 1.491, 95% CI: 1.107-2.007; P = 0.009) was an independent risk factor for overall survival in HCC patients. Finally, we confirmed that si-hMex-3A could significantly inhibit HCC cell proliferation, migration, and invasion in vitro. CONCLUSIONS HMex-3A may contribute to the progression of HCC and might be used as a novel therapeutic target and prognostic marker in HCC.
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Affiliation(s)
- Yi-Fan Liu
- Zhengzhou Key Laboratory of Hepatobiliary and Pancreatic Diseases and Organ Transplantation, Zhengzhou 450052, China; Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou 450052, China
| | - Xiao-Yan Sun
- Zhengzhou Key Laboratory of Hepatobiliary and Pancreatic Diseases and Organ Transplantation, Zhengzhou 450052, China; Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou 450052, China
| | - Jia-Kai Zhang
- Department of Hepatobiliary and Pancreatic Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China; Open and Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Zhi-Hui Wang
- Department of Hepatobiliary and Pancreatic Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China; Open and Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Zhi-Gang Ren
- Department of Infectious Diseases, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Jie Li
- Zhengzhou Key Laboratory of Hepatobiliary and Pancreatic Diseases and Organ Transplantation, Zhengzhou 450052, China; Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou 450052, China
| | - Wen-Zhi Guo
- Zhengzhou Key Laboratory of Hepatobiliary and Pancreatic Diseases and Organ Transplantation, Zhengzhou 450052, China; Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou 450052, China; Department of Hepatobiliary and Pancreatic Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China; Open and Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Shui-Jun Zhang
- Zhengzhou Key Laboratory of Hepatobiliary and Pancreatic Diseases and Organ Transplantation, Zhengzhou 450052, China; Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou 450052, China; Department of Hepatobiliary and Pancreatic Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China; Open and Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China.
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Liu Y, Jing X, Zhang H, Xiong J, Qiao Y. Identification of Imprinted Genes Based on Homology: An Example of Fragaria vesca. Genes (Basel) 2021; 12:genes12030380. [PMID: 33800118 PMCID: PMC7999015 DOI: 10.3390/genes12030380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/28/2021] [Accepted: 03/04/2021] [Indexed: 01/04/2023] Open
Abstract
Genomic imprinting has drawn increasing attention in plant biology in recent years. At present, hundreds of imprinted genes have been identified in various plants, and some of them have been reported to be evolutionarily conserved in plant species. In this research, 17 candidate genes in Fragaria vesca were obtained based on the homologous imprinted genes in Arabidopsis thaliana and other species. We further constructed reciprocal crosses of diploid strawberry (F. vesca) using the varieties 10-41 and 18-86 as the parents to investigate the conservation of these imprinted genes. Potentially informative single nucleotide polymorphisms (SNPs) were used as molecular markers of two parents obtained from candidate imprinted genes which have been cloned and sequenced. Meanwhile, we analyzed the SNP site variation ratios and parent-of-origin expression patterns of candidate imprinted genes at 10 days after pollination (DAP) endosperm and embryo for the hybrids of reciprocal cross, respectively. A total of five maternally expressed genes (MEGs), i.e., FvARI8, FvKHDP-2, FvDRIP2, FvBRO1, and FvLTP3, were identified in the endosperm, which did not show imprinting in the embryo. Finally, tissues expression analysis indicated that the five imprinted genes excluding FvDRIP2 mainly expressed in the endosperm. This is the first report on imprinted genes of Fragaria, and we provide a simple and rapid method based on homologous conservation to screen imprinted genes. The present study will provide a basis for further study of function and mechanism of genomic imprinting in F. vesca.
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Mukherjee N, Mukherjee C. Germ cell ribonucleoprotein granules in different clades of life: From insects to mammals. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1642. [PMID: 33555143 DOI: 10.1002/wrna.1642] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 12/12/2022]
Abstract
Ribonucleoprotein (RNP) granules are no newcomers in biology. Found in all life forms, ranging across taxa, these membrane-less "organelles" have been classified into different categories based on their composition, structure, behavior, function, and localization. Broadly, they can be listed as stress granules (SGs), processing bodies (PBs), neuronal granules (NGs), and germ cell granules (GCGs). Keeping in line with the topic of this review, RNP granules present in the germ cells have been implicated in a wide range of cellular functions including cellular specification, differentiation, proliferation, and so forth. The mechanisms used by them can be diverse and many of them remain partly obscure and active areas of research. GCGs can be of different types in different organisms and at different stages of development, with multiple types coexisting in the same cell. In this review, the different known subcategories of GCGs have been studied with respect to five distinct model organisms, namely, Drosophila, Caenorhabditis elegans, Xenopus, Zebrafish, and mammals. Of them, the cytoplasmic polar granules in Drosophila, P granules in C. elegans, balbiani body in Xenopus and Zebrafish, and chromatoid bodies in mammals have been specifically emphasized upon. A descriptive account of the same has been provided along with insights into our current understanding of their functional significance with respect to cellular events relating to different developmental and reproductive processes. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Export and Localization > RNA Localization RNA in Disease and Development > RNA in Disease.
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22
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Sundby AE, Molnar RI, Claycomb JM. Connecting the Dots: Linking Caenorhabditis elegans Small RNA Pathways and Germ Granules. Trends Cell Biol 2021; 31:387-401. [PMID: 33526340 DOI: 10.1016/j.tcb.2020.12.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 12/15/2022]
Abstract
Germ granules are non-membrane bound, phase-separated organelles, composed of RNAs and proteins. Germ granules are present only within the germ cells of animals, including model systems such as Caenorhabditis elegans, Drosophila, mice, and zebrafish, where they play critical roles in specifying the germ lineage, the inheritance of epigenetic information, and post-transcriptional gene regulation. Across species, conserved germ granule proteins reflect these essential functions. A significant proportion of proteins that localize to germ granules are components of RNA metabolism and small RNA (sRNA) gene regulatory pathways. Here we synthesize our current knowledge of the roles that germ granules and their components play in sRNA pathway functions, transgenerational inheritance, and fertility in the C. elegans germline.
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Affiliation(s)
- Adam E Sundby
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ruxandra I Molnar
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Julie M Claycomb
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
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23
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Yang C, Zhan H, Zhao Y, Wu Y, Li L, Wang H. MEX3A contributes to development and progression of glioma through regulating cell proliferation and cell migration and targeting CCL2. Cell Death Dis 2021; 12:14. [PMID: 33414423 PMCID: PMC7791131 DOI: 10.1038/s41419-020-03307-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 11/03/2020] [Accepted: 11/05/2020] [Indexed: 01/03/2023]
Abstract
Glioma is one of the most commonly diagnosed intracranial malignant tumors with extremely high morbidity and mortality, whose treatment was seriously limited because of the unclear molecular mechanism. In this study, in order to identify a novel therapeutic target for glioma treatment, we explored the functions and mechanism of MEX3A in regulating glioma. The immunohistochemical staining of MEX3A in glioma and normal tissues revealed the upregulation of MEX3A and further indicated the relationship between high MEX3A expression and higher malignancy as well as poorer prognosis of glioma. In vitro loss-of-function and gain-of-function experiments comprehensively demonstrated that MEX3A may promote glioma development through regulating cell proliferation, cell apoptosis, cell cycle, and cell migration. In vivo experiments also suggested the inhibition of glioma growth by MEX3A knockdown. Moreover, our mechanistic study identifies CCL2 as a potential downstream target of MEX3A, which possesses similar regulatory effects on glioma development with MEX3A and could attenuate the promotion of glioma induced by MEX3A overexpression. Overall, MEX3A was identified as a potential tumor promoter in glioma development and therapeutic target in glioma treatment.
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Affiliation(s)
- Chao Yang
- Department of Neurosurgery, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China
| | - Haoqiang Zhan
- Department of Neurosurgery, The Six Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Yiqing Zhao
- Department of Neurosurgery, TongJi hospital of TongJi Medical College, Huazhong University of Science and Technology, Hankou, Wuhan, 430030, China
| | - Yasong Wu
- Department of Neurosurgery, TongJi hospital of TongJi Medical College, Huazhong University of Science and Technology, Hankou, Wuhan, 430030, China
| | - Lisha Li
- The Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130012, China
| | - Heping Wang
- Department of Neurosurgery, TongJi hospital of TongJi Medical College, Huazhong University of Science and Technology, Hankou, Wuhan, 430030, China.
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24
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Wei L, Wang B, Hu L, Xu Y, Li Z, Shen Y, Huang H. MEX3A is upregulated in esophageal squamous cell carcinoma (ESCC) and promotes development and progression of ESCC through targeting CDK6. Aging (Albany NY) 2020; 12:21091-21113. [PMID: 33188661 PMCID: PMC7695430 DOI: 10.18632/aging.103196] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 04/13/2020] [Indexed: 02/07/2023]
Abstract
Esophageal squamous cell carcinoma (ESCC) is one of the most commonly diagnosed malignant tumors worldwide and identified as a serious threat to human health. The role of MEX3A in ESCC remains unclear. In this study, we found that MEX3A was upregulated in tumor tissues of ESCC and positively associated with more advanced tumor stage, higher risk of lymphatic metastasis and poor prognosis. The downregulation of MEX3A in ESCC cell lines could induce inhibition of cell proliferation, colony formation, cell migration, and the promotion of cell apoptosis, while MEX3A overexpression exhibited opposite effects. In vivo experiments also verified the inhibition of ESCC induced by MEX3A knockdown. Moreover, we identified CDK6 as a potential target of MEX3A, which was also upregulated in ESCC. Further studies demonstrated that knockdown of CDK6 showed similar effects on the development of ESCC with MEX3A. More importantly, it was illustrated that CDK6 knockdown could alleviate the promotion effects of MEX3A overexpression on ESCC. In conclusion, MEX3A was identified as a tumor promotor in the development and progression of ESCC by targeting CDK6, which may be considered as a novel prognostic indicator and therapeutic target in treatment of ESCC.
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Affiliation(s)
- Lei Wei
- Department of Cardiothoracic Surgery, Jinling Hospital, Nanjing 210002, China
| | - Bo Wang
- Department of Thoracic Surgery, Nanjing Chest Hospital, Nanjing 210029, China
| | - Liwen Hu
- Department of Cardiothoracic Surgery, Jinling Hospital, Nanjing 210002, China
| | - Yang Xu
- Department of Cardiothoracic Surgery, Jinling Hospital, Nanjing 210002, China
| | - Zhongdong Li
- Department of Cardiothoracic Surgery, Jinling Hospital, Nanjing 210002, China
| | - Yi Shen
- Department of Cardiothoracic Surgery, Jinling Hospital, Nanjing 210002, China
| | - Hairong Huang
- Department of Cardiothoracic Surgery, Jinling Hospital, Nanjing 210002, China
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25
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Naef V, De Sarlo M, Testa G, Corsinovi D, Azzarelli R, Borello U, Ori M. The Stemness Gene Mex3A Is a Key Regulator of Neuroblast Proliferation During Neurogenesis. Front Cell Dev Biol 2020; 8:549533. [PMID: 33072742 PMCID: PMC7536324 DOI: 10.3389/fcell.2020.549533] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/31/2020] [Indexed: 01/31/2023] Open
Abstract
Mex3A is an RNA binding protein that can also act as an E3 ubiquitin ligase to control gene expression at the post-transcriptional level. In intestinal adult stem cells, MEX3A is required for cell self-renewal and when overexpressed, MEX3A can contribute to support the proliferation of different cancer cell types. In a completely different context, we found mex3A among the genes expressed in neurogenic niches of the embryonic and adult fish brain and, notably, its expression was downregulated during brain aging. The role of mex3A during embryonic and adult neurogenesis in tetrapods is still unknown. Here, we showed that mex3A is expressed in the proliferative region of the developing brain in both Xenopus and mouse embryos. Using gain and loss of gene function approaches, we showed that, in Xenopus embryos, mex3A is required for neuroblast proliferation and its depletion reduced the neuroblast pool, leading to microcephaly. The tissue-specific overexpression of mex3A in the developing neural plate enhanced the expression of sox2 and msi-1 keeping neuroblasts into a proliferative state. It is now clear that the stemness property of mex3A, already demonstrated in adult intestinal stem cells and cancer cells, is a key feature of mex3a also in developing brain, opening new lines of investigation to better understand its role during brain aging and brain cancer development.
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Affiliation(s)
- Valentina Naef
- Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy.,Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Miriam De Sarlo
- Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | - Giovanna Testa
- Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy.,Scuola Normale Superiore di Pisa, Pisa, Italy
| | - Debora Corsinovi
- Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | - Roberta Azzarelli
- Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | - Ugo Borello
- Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | - Michela Ori
- Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy
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26
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Jasinski-Bergner S, Steven A, Seliger B. The Role of the RNA-Binding Protein Family MEX-3 in Tumorigenesis. Int J Mol Sci 2020; 21:ijms21155209. [PMID: 32717840 PMCID: PMC7432607 DOI: 10.3390/ijms21155209] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/16/2020] [Accepted: 07/21/2020] [Indexed: 12/16/2022] Open
Abstract
The muscle excess 3 (MEX-3) protein was first identified in Caenorhabditis elegans (C. elegans), and its respective homologues were also observed in vertebrates, including humans. It is a RNA-binding protein (RBP) with an additional ubiquitin E3 ligase function, which further acts as a post-transcriptional repressor through unknown mechanisms. In humans, MEX-3 proteins post-transcriptionally regulate a number of biological processes, including tumor immunological relevant ones. These have been shown to be involved in various diseases, including tumor diseases of distinct origins. This review provides information on the expression and function of the human MEX-3 family in healthy tissues, as well after malignant transformation. Indeed, the MEX-3 expression was shown to be deregulated in several cancers and to affect tumor biological functions, including apoptosis regulation, antigen processing, and presentation, thereby, contributing to the immune evasion of tumor cells. Furthermore, current research suggests MEX-3 proteins as putative markers for prognosis and as novel targets for the anti-cancer treatment.
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Affiliation(s)
| | | | - Barbara Seliger
- Correspondence: ; Tel.: +49-345-557-1357; Fax: +49-345-557-4055
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27
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Pereira B, Amaral AL, Dias A, Mendes N, Muncan V, Silva AR, Thibert C, Radu AG, David L, Máximo V, van den Brink GR, Billaud M, Almeida R. MEX3A regulates Lgr5 + stem cell maintenance in the developing intestinal epithelium. EMBO Rep 2020; 21:e48938. [PMID: 32052574 PMCID: PMC7132344 DOI: 10.15252/embr.201948938] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 01/15/2020] [Accepted: 01/20/2020] [Indexed: 12/12/2022] Open
Abstract
Intestinal stem cells (ISCs) fuel the lifelong self‐renewal of the intestinal tract and are paramount for epithelial repair. In this context, the Wnt pathway component LGR5 is the most consensual ISC marker to date. Still, the effort to better understand ISC identity and regulation remains a challenge. We have generated a Mex3a knockout mouse model and show that this RNA‐binding protein is crucial for the maintenance of the Lgr5+ISC pool, as its absence disrupts epithelial turnover during postnatal development and stereotypical organoid maturation ex vivo. Transcriptomic profiling of intestinal crypts reveals that Mex3a deletion induces the peroxisome proliferator‐activated receptor (PPAR) pathway, along with a decrease in Wnt signalling and loss of the Lgr5+ stem cell signature. Furthermore, we identify PPARγ activity as a molecular intermediate of MEX3A‐mediated regulation. We also show that high PPARγ signalling impairs Lgr5+ISC function, thus uncovering a new layer of post‐transcriptional regulation that critically contributes to intestinal homeostasis.
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Affiliation(s)
- Bruno Pereira
- i3S - Institute for Research and Innovation in Health (Instituto de Investigação e Inovação em Saúde), University of Porto, Porto, Portugal.,IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal
| | - Ana L Amaral
- i3S - Institute for Research and Innovation in Health (Instituto de Investigação e Inovação em Saúde), University of Porto, Porto, Portugal.,IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal
| | - Alexandre Dias
- i3S - Institute for Research and Innovation in Health (Instituto de Investigação e Inovação em Saúde), University of Porto, Porto, Portugal.,IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal
| | - Nuno Mendes
- i3S - Institute for Research and Innovation in Health (Instituto de Investigação e Inovação em Saúde), University of Porto, Porto, Portugal.,IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal
| | - Vanesa Muncan
- Department of Gastroenterology and Hepatology, Amsterdam UMC, Tytgat Institute, University of Amsterdam, Amsterdam, The Netherlands
| | - Ana R Silva
- i3S - Institute for Research and Innovation in Health (Instituto de Investigação e Inovação em Saúde), University of Porto, Porto, Portugal.,IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal
| | - Chantal Thibert
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Anca G Radu
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Leonor David
- i3S - Institute for Research and Innovation in Health (Instituto de Investigação e Inovação em Saúde), University of Porto, Porto, Portugal.,IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal.,FMUP-Faculty of Medicine, University of Porto, Porto, Portugal
| | - Valdemar Máximo
- i3S - Institute for Research and Innovation in Health (Instituto de Investigação e Inovação em Saúde), University of Porto, Porto, Portugal.,IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal.,FMUP-Faculty of Medicine, University of Porto, Porto, Portugal
| | - Gijs R van den Brink
- Department of Gastroenterology and Hepatology, Amsterdam UMC, Tytgat Institute, University of Amsterdam, Amsterdam, The Netherlands.,Medicines Research Center, GSK, Stevenage, UK
| | - Marc Billaud
- Clinical and Experimental Model of Lymphomagenesis, INSERM U1052, CNRS UMR5286, Centre Léon Bérard, Université Claude Bernard Lyon 1, Centre de Recherche en Cancérologie de Lyon, Lyon, France
| | - Raquel Almeida
- i3S - Institute for Research and Innovation in Health (Instituto de Investigação e Inovação em Saúde), University of Porto, Porto, Portugal.,IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal.,FMUP-Faculty of Medicine, University of Porto, Porto, Portugal.,Biology Department, Faculty of Sciences, University of Porto, Porto, Portugal
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28
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Rocha de Almeida T, Alix M, Le Cam A, Klopp C, Montfort J, Toomey L, Ledoré Y, Bobe J, Chardard D, Schaerlinger B, Fontaine P. Domestication may affect the maternal mRNA profile in unfertilized eggs, potentially impacting the embryonic development of Eurasian perch (Perca fluviatilis). PLoS One 2019; 14:e0226878. [PMID: 31891603 PMCID: PMC6938363 DOI: 10.1371/journal.pone.0226878] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 12/06/2019] [Indexed: 12/18/2022] Open
Abstract
Domestication is an evolutionary process during which we expect populations to progressively adapt to an environment controlled by humans. It is accompanied by genetic and presumably epigenetic changes potentially leading to modifications in the transcriptomic profile in various tissues. Reproduction is a key function often affected by this process in numerous species, regardless of the mechanism. The maternal mRNA in fish eggs is crucial for the proper embryogenesis. Our working hypothesis is that modifications of maternal mRNAs may reflect potential genetic and/or epigenetic modifications occurring during domestication and could have consequences during embryogenesis. Consequently, we investigated the trancriptomic profile of unfertilized eggs from two populations of Eurasian perch. These two populations differed by their domestication histories (F1 vs. F7+-at least seven generations of reproduction in captivity) and were genetically differentiated (FST = 0.1055, p<0.05). A broad follow up of the oogenesis progression failed to show significant differences during oogenesis between populations. However, the F1 population spawned earlier with embryos presenting an overall higher survivorship than those from the F7+ population. The transcriptomic profile of unfertilized eggs showed 358 differentially expressed genes between populations. In conclusion, our data suggests that the domestication process may influence the regulation of the maternal transcripts in fish eggs, which could in turn explain differences of developmental success.
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Affiliation(s)
| | - Maud Alix
- UR AFPA, University of Lorraine, INRA, Nancy, France
| | - Aurélie Le Cam
- LPGP, UR1037 Fish Physiology and Genomics, INRA, Rennes, France
| | | | - Jérôme Montfort
- LPGP, UR1037 Fish Physiology and Genomics, INRA, Rennes, France
| | - Lola Toomey
- UR AFPA, University of Lorraine, INRA, Nancy, France
| | | | - Julien Bobe
- LPGP, UR1037 Fish Physiology and Genomics, INRA, Rennes, France
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29
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Flora P, Wong-Deyrup SW, Martin ET, Palumbo RJ, Nasrallah M, Oligney A, Blatt P, Patel D, Fuchs G, Rangan P. Sequential Regulation of Maternal mRNAs through a Conserved cis-Acting Element in Their 3' UTRs. Cell Rep 2019; 25:3828-3843.e9. [PMID: 30590052 PMCID: PMC6328254 DOI: 10.1016/j.celrep.2018.12.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 10/28/2018] [Accepted: 11/30/2018] [Indexed: 12/31/2022] Open
Abstract
Maternal mRNAs synthesized during oogenesis initiate the development of future generations. Some maternal mRNAs are either somatic or germline determinants and must be translationally repressed until embryogenesis. However, the translational repressors themselves are temporally regulated. We used polar granule component (pgc), a Drosophila maternal mRNA, to ask how maternal transcripts are repressed while the regulatory landscape is shifting. pgc, a germline determinant, is translationally regulated throughout oogenesis. We find that different conserved RNA-binding proteins bind a 10-nt sequence in the 3′ UTR of pgc mRNA to continuously repress translation at different stages of oogenesis. Pumilio binds to this sequence in undifferentiated and early-differentiating oocytes to block Pgc translation. After differentiation, Bruno levels increase, allowing Bruno to bind the same sequence and take over translational repression of pgc mRNA. We have identified a class of maternal mRNAs that are regulated similarly, including zelda, the activator of the zygotic genome. Flora et al. show that pgc, a germline determinant, is translationally regulated throughout oogenesis. Different conserved RBPs bind a 10-nt sequence in the 3′ UTR to continuously repress translation throughout oogenesis. This mode of regulation applies to a class of maternal mRNAs, including zelda, the activator of the zygotic genome.
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Affiliation(s)
- Pooja Flora
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Siu Wah Wong-Deyrup
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Elliot Todd Martin
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Ryan J Palumbo
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Mohamad Nasrallah
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Andrew Oligney
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Patrick Blatt
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Dhruv Patel
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Gabriele Fuchs
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Prashanth Rangan
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA.
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30
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Rothman J, Jarriault S. Developmental Plasticity and Cellular Reprogramming in Caenorhabditis elegans. Genetics 2019; 213:723-757. [PMID: 31685551 PMCID: PMC6827377 DOI: 10.1534/genetics.119.302333] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 07/25/2019] [Indexed: 12/28/2022] Open
Abstract
While Caenorhabditis elegans was originally regarded as a model for investigating determinate developmental programs, landmark studies have subsequently shown that the largely invariant pattern of development in the animal does not reflect irreversibility in rigidly fixed cell fates. Rather, cells at all stages of development, in both the soma and germline, have been shown to be capable of changing their fates through mutation or forced expression of fate-determining factors, as well as during the normal course of development. In this chapter, we review the basis for natural and induced cellular plasticity in C. elegans We describe the events that progressively restrict cellular differentiation during embryogenesis, starting with the multipotency-to-commitment transition (MCT) and subsequently through postembryonic development of the animal, and consider the range of molecular processes, including transcriptional and translational control systems, that contribute to cellular plasticity. These findings in the worm are discussed in the context of both classical and recent studies of cellular plasticity in vertebrate systems.
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Affiliation(s)
- Joel Rothman
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93111, and
| | - Sophie Jarriault
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Department of Development and Stem Cells, CNRS UMR7104, Inserm U1258, Université de Strasbourg, 67404 Illkirch CU Strasbourg, France
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31
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Quan H, Arsala D, Lynch JA. Transcriptomic and functional analysis of the oosome, a unique form of germ plasm in the wasp Nasonia vitripennis. BMC Biol 2019; 17:78. [PMID: 31601213 PMCID: PMC6785909 DOI: 10.1186/s12915-019-0696-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 08/30/2019] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND The oosome is the germline determinant in the wasp Nasonia vitripennis and is homologous to the polar granules of Drosophila. Despite a common evolutionary origin and developmental role, the oosome is morphologically quite distinct from polar granules. It is a solid sphere that migrates within the cytoplasm before budding out and forming pole cells. RESULTS To gain an understanding of both the molecular basis of oosome development and the conserved essential features of germ plasm, we quantified and compared transcript levels between embryo fragments that contained the oosome and those that did not. The identity of the differentially localized transcripts indicated that Nasonia uses a distinct set of molecules to carry out conserved germ plasm functions. In addition, functional testing of a sample of localized transcripts revealed potentially novel mechanisms of ribonucleoprotein assembly and pole cell cellularization in the wasp. CONCLUSIONS Our results demonstrate that the composition of germ plasm varies significantly within Holometabola, as very few mRNAs share localization to the oosome and polar granules. Some of this variability appears to be related to the unique properties of the oosome relative to the polar granules in Drosophila, and some may be related to differences in pole formation between species. This work will serve as the basis for further investigation into the patterns of germline determinant evolution among insects, the molecular basis of the unique properties of the oosome, and the incorporation of novel components into developmental networks.
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Affiliation(s)
- Honghu Quan
- Department of Pathology and Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105 USA
| | - Deanna Arsala
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607 USA
| | - Jeremy A. Lynch
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607 USA
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32
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Wang S, Ochoa SD, Khaliullin RN, Gerson-Gurwitz A, Hendel JM, Zhao Z, Biggs R, Chisholm AD, Desai A, Oegema K, Green RA. A high-content imaging approach to profile C. elegans embryonic development. Development 2019; 146:dev174029. [PMID: 30890570 PMCID: PMC6467471 DOI: 10.1242/dev.174029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 03/11/2019] [Indexed: 11/20/2022]
Abstract
The Caenorhabditis elegans embryo is an important model for analyzing mechanisms of cell fate specification and tissue morphogenesis. Sophisticated lineage-tracing approaches for analyzing embryogenesis have been developed but are labor intensive and do not naturally integrate morphogenetic readouts. To enable the rapid classification of developmental phenotypes, we developed a high-content method that employs two custom strains: a Germ Layer strain that expresses nuclear markers in the ectoderm, mesoderm and endoderm/pharynx; and a Morphogenesis strain that expresses markers labeling epidermal cell junctions and the neuronal cell surface. We describe a procedure that allows simultaneous live imaging of development in 80-100 embryos and provide a custom program that generates cropped, oriented image stacks of individual embryos to facilitate analysis. We demonstrate the utility of our method by perturbing 40 previously characterized developmental genes in variants of the two strains containing RNAi-sensitizing mutations. The resulting datasets yielded distinct, reproducible signature phenotypes for a broad spectrum of genes that are involved in cell fate specification and morphogenesis. In addition, our analysis provides new in vivo evidence for MBK-2 function in mesoderm fate specification and LET-381 function in elongation.
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Affiliation(s)
- Shaohe Wang
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stacy D Ochoa
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Renat N Khaliullin
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Adina Gerson-Gurwitz
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Jeffrey M Hendel
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Zhiling Zhao
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Ronald Biggs
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Andrew D Chisholm
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Arshad Desai
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Karen Oegema
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Rebecca A Green
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
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33
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Linz DM, Hu Y, Moczek AP. The origins of novelty from within the confines of homology: the developmental evolution of the digging tibia of dung beetles. Proc Biol Sci 2019; 286:20182427. [PMID: 30963933 PMCID: PMC6408602 DOI: 10.1098/rspb.2018.2427] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 01/23/2019] [Indexed: 11/12/2022] Open
Abstract
Understanding the origin of novel complex traits is among the most fundamental goals in evolutionary biology. The most widely used definition of novelty in evolution assumes the absence of homology, yet where homology ends and novelty begins is increasingly difficult to parse as evo devo continuously revises our understanding of what constitutes homology. Here, we executed a case study to explore the earliest stages of innovation by examining the tibial teeth of tunnelling dung beetles. Tibial teeth are a morphologically modest innovation, composed of relatively simple body wall projections and contained fully within the fore tibia, a leg segment whose own homology status is unambiguous. We first demonstrate that tibial teeth aid in multiple digging behaviours. We then show that the developmental evolution of tibial teeth was dominated by the redeployment of locally pre-existing gene networks. At the same time, we find that even at this very early stage of innovation, at least two genes that ancestrally function in embryonic patterning and thus entirely outside the spatial and temporal context of leg formation, have already become recruited to help shape the formation of tibial teeth. Our results suggest a testable model for how developmental evolution scaffolds innovation.
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Multiple Mechanisms Inactivate the LIN-41 RNA-Binding Protein To Ensure a Robust Oocyte-to-Embryo Transition in Caenorhabditis elegans. Genetics 2018; 210:1011-1037. [PMID: 30206186 PMCID: PMC6218228 DOI: 10.1534/genetics.118.301421] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 09/10/2018] [Indexed: 12/23/2022] Open
Abstract
In the nematode Caenorhabditis elegans, the conserved LIN-41 RNA-binding protein is a translational repressor that coordinately controls oocyte growth and meiotic maturation. LIN-41 exerts these effects, at least in part, by preventing the premature activation of the cyclin-dependent kinase CDK-1. Here we investigate the mechanism by which LIN-41 is rapidly eliminated upon the onset of meiotic maturation. Elimination of LIN-41 requires the activities of CDK-1 and multiple SCF (Skp1, Cul1, and F-box protein)-type E3 ubiquitin ligase subunits, including the conserved substrate adaptor protein SEL-10/Fbw7/Cdc4, suggesting that LIN-41 is a target of ubiquitin-mediated protein degradation. Within the LIN-41 protein, two nonoverlapping regions, Deg-A and Deg-B, are individually necessary for LIN-41 degradation; both contain several potential phosphodegron sequences, and at least one of these sequences is required for LIN-41 degradation. Finally, Deg-A and Deg-B are sufficient, in combination, to mediate SEL-10-dependent degradation when transplanted into a different oocyte protein. Although LIN-41 is a potent inhibitor of protein translation and M phase entry, the failure to eliminate LIN-41 from early embryos does not result in the continued translational repression of LIN-41 oocyte messenger RNA targets. Based on these observations, we propose a model for the elimination of LIN-41 by the SEL-10 E3 ubiquitin ligase and suggest that LIN-41 is inactivated before it is degraded. Furthermore, we provide evidence that another RNA-binding protein, the GLD-1 tumor suppressor, is regulated similarly. Redundant mechanisms to extinguish translational repression by RNA-binding proteins may both control and provide robustness to irreversible developmental transitions, including meiotic maturation and the oocyte-to-embryo transition.
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Spickard EA, Joshi PM, Rothman JH. The multipotency-to-commitment transition in Caenorhabditis elegans-implications for reprogramming from cells to organs. FEBS Lett 2018; 592:838-851. [PMID: 29334121 DOI: 10.1002/1873-3468.12977] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 12/22/2017] [Accepted: 01/11/2018] [Indexed: 12/13/2022]
Abstract
In animal embryos, cells transition from a multipotential state, with the capacity to adopt multiple fates, into an irreversible, committed state of differentiation. This multipotency-to-commitment transition (MCT) is evident from experiments in which cell fate is reprogrammed by transcription factors for cell type-specific differentiation, as has been observed extensively in Caenorhabditis elegans. Although factors that direct differentiation into each of the three germ layer types cannot generally reprogram cells after the MCT in this animal, transcription factors for endoderm development are able to do so in multiple differentiated cell types. In one case, these factors can redirect the development of an entire organ in the process of "transorganogenesis". Natural transdifferentiation also occurs in a small number of differentiated cells during normal C. elegans development. We review these reprogramming and transdifferentiation events, highlighting the cellular and developmental contexts in which they occur, and discuss common themes underlying direct cell lineage reprogramming. Although certain aspects may be unique to the model system, growing evidence suggests that some mechanisms are evolutionarily conserved and may shed light on cellular plasticity and disease in humans.
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Affiliation(s)
- Erik A Spickard
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, CA, USA
| | - Pradeep M Joshi
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, CA, USA
| | - Joel H Rothman
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, CA, USA
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Yang L, Wang C, Li F, Zhang J, Nayab A, Wu J, Shi Y, Gong Q. The human RNA-binding protein and E3 ligase MEX-3C binds the MEX-3-recognition element (MRE) motif with high affinity. J Biol Chem 2017; 292:16221-16234. [PMID: 28808060 DOI: 10.1074/jbc.m117.797746] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 08/05/2017] [Indexed: 11/06/2022] Open
Abstract
MEX-3 is a K-homology (KH) domain-containing RNA-binding protein first identified as a translational repressor in Caenorhabditis elegans, and its four orthologs (MEX-3A-D) in human and mouse were subsequently found to have E3 ubiquitin ligase activity mediated by a RING domain and critical for RNA degradation. Current evidence implicates human MEX-3C in many essential biological processes and suggests a strong connection with immune diseases and carcinogenesis. The highly conserved dual KH domains in MEX-3 proteins enable RNA binding and are essential for the recognition of the 3'-UTR and post-transcriptional regulation of MEX-3 target transcripts. However, the molecular mechanisms of translational repression and the consensus RNA sequence recognized by the MEX-3C KH domain are unknown. Here, using X-ray crystallography and isothermal titration calorimetry, we investigated the RNA-binding activity and selectivity of human MEX-3C dual KH domains. Our high-resolution crystal structures of individual KH domains complexed with a noncanonical U-rich and a GA-rich RNA sequence revealed that the KH1/2 domains of human MEX-3C bound MRE10, a 10-mer RNA (5'-CAGAGUUUAG-3') consisting of an eight-nucleotide MEX-3-recognition element (MRE) motif, with high affinity. Of note, we also identified a consensus RNA motif recognized by human MEX-3C. The potential RNA-binding sites in the 3'-UTR of the human leukocyte antigen serotype (HLA-A2) mRNA were mapped with this RNA-binding motif and further confirmed by fluorescence polarization. The binding motif identified here will provide valuable information for future investigations of the functional pathways controlled by human MEX-3C and for predicting potential mRNAs regulated by this enzyme.
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Affiliation(s)
- Lingna Yang
- From the Hefei National Laboratory for Physical Science at Microscale, Collaborative Innovation Center of Chemistry for Life Sciences and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Chongyuan Wang
- From the Hefei National Laboratory for Physical Science at Microscale, Collaborative Innovation Center of Chemistry for Life Sciences and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Fudong Li
- From the Hefei National Laboratory for Physical Science at Microscale, Collaborative Innovation Center of Chemistry for Life Sciences and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Jiahai Zhang
- From the Hefei National Laboratory for Physical Science at Microscale, Collaborative Innovation Center of Chemistry for Life Sciences and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Anam Nayab
- From the Hefei National Laboratory for Physical Science at Microscale, Collaborative Innovation Center of Chemistry for Life Sciences and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Jihui Wu
- From the Hefei National Laboratory for Physical Science at Microscale, Collaborative Innovation Center of Chemistry for Life Sciences and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Yunyu Shi
- From the Hefei National Laboratory for Physical Science at Microscale, Collaborative Innovation Center of Chemistry for Life Sciences and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and.,CAS Center for Excellence in Biomacromolecules, Chinese Academy of Sciences, Beijing 100101, China
| | - Qingguo Gong
- From the Hefei National Laboratory for Physical Science at Microscale, Collaborative Innovation Center of Chemistry for Life Sciences and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
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Jeremias WDJ, Araújo FMG, Queiroz FR, Pais FSM, de Mattos ACA, Salim ACDM, Coelho PMZ, Oliveira GC, Kusel JR, Guerra-Sá R, Coimbra RS, Babá ÉH. Comparative sequence analysis reveals regulation of genes in developing schistosomula of Schistosoma mansoni exposed to host portal serum. PLoS One 2017. [PMID: 28622369 PMCID: PMC5473564 DOI: 10.1371/journal.pone.0178829] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Once inside a vertebrate host after infection, individual schistosomula of the parasite Schistosoma mansoni find a new and complex environment, which requires quick adjustments for survival, such as those that allow it to avoid the innate immune response of the host. Thus, it is very important for the parasite to remain within the skin after entering the host for a period of about 3 days, at which time it can then reach the venous system, migrate to the lungs and, by the end of eighth day post-infection, it reach the portal venous system, while undergoing minimal changes in morphology. However, after just a few days in the portal blood system, the parasite experiences an extraordinary increase in biomass and significant morphological alterations. Therefore, determining the constituents of the portal venous system that may trigger these changes that causes the parasite to consolidate its development inside the vertebrate host, thus causing the disease schistosomiasis, is essential. The present work simulated the conditions found in the portal venous system of the vertebrate host by exposing schistosomula of S. mansoni to in vitro culture in the presence of portal serum of the hamster, Mesocricetus auratus. Two different incubation periods were evaluated, one of 3 hours and one of 12 hours. These time periods were used to mimic the early contact of the parasite with portal serum during the course of natural infection. As a control, parasites were incubated in presence of hamster peripheral serum, in order to compare gene expression signatures between the two conditions. The mRNA obtained from parasites cultured under both conditions were submitted to a whole transcriptome library preparation and sequenced with a next generation platform. On average, nearly 15 million reads were produced per sample and, for the purpose of gene expression quantification, only reads mapped to one location of the transcriptome were considered. After statistical analysis, we found 103 genes differentially expressed by schistosomula cultured for 3 hours and 12 hours in the presence of hamster portal serum. After the subtraction of a second list of genes, also differentially expressed between schistosomula cultured for 3 hours and 12 hours in presence of peripheral serum, a set of 58 genes was finally established. This pattern was further validated for a subset of 17 genes, by measuring gene expression through quantitative real time polymerase chain reaction (qPCR). Processes that were activated by the portal serum stimulus include response to stress, membrane transport, protein synthesis and folding/degradation, signaling, cytoskeleton arrangement, cell adhesion and nucleotide synthesis. Additionally, a smaller number of genes down-regulated under the same condition act on cholinergic signaling, inorganic cation and organic anion membrane transport, cell adhesion and cytoskeleton arrangement. Considering the role of these genes in triggering processes that allow the parasite to quickly adapt, escape the immune response of the host and start maturation into an adult worm after contact with the portal serum, this work may point to unexplored molecular targets for drug discovery and vaccine development against schistosomiasis.
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Affiliation(s)
- Wander de Jesus Jeremias
- René Rachou, Oswaldo Cruz Foundation – FIOCRUZ-MG, Belo Horizonte, Minas Gerais, Brazil
- Centro Universitário de Belo Horizonte – UNIBH, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
| | | | - Fábio Ribeiro Queiroz
- René Rachou, Oswaldo Cruz Foundation – FIOCRUZ-MG, Belo Horizonte, Minas Gerais, Brazil
| | | | | | | | | | - Guilherme Correa Oliveira
- René Rachou, Oswaldo Cruz Foundation – FIOCRUZ-MG, Belo Horizonte, Minas Gerais, Brazil
- Instituto Tecnológico Vale, Belém, Pará, Brazil
| | - John Robert Kusel
- Glasgow University, Centre for Open Studies, Glasgow, United Kingdom
| | - Renata Guerra-Sá
- Federal University of Ouro Preto, Institute of Exact and Biological Sciences, Ouro Preto, Minas Gerais, Brazil
| | - Roney Santos Coimbra
- René Rachou, Oswaldo Cruz Foundation – FIOCRUZ-MG, Belo Horizonte, Minas Gerais, Brazil
| | - Élio Hideo Babá
- René Rachou, Oswaldo Cruz Foundation – FIOCRUZ-MG, Belo Horizonte, Minas Gerais, Brazil
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Shi JW, Huang Y. Mex3a expression and survival analysis of bladder urothelial carcinoma. Oncotarget 2017; 8:54764-54774. [PMID: 28903380 PMCID: PMC5589619 DOI: 10.18632/oncotarget.18399] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 05/27/2017] [Indexed: 01/01/2023] Open
Abstract
Objective Bladder urothelial carcinoma is a common tumor in humans and a multifactorial disease. The gene mex3a is associated with tumor formation and may promote cell proliferation and migration. Therefore, this study aimed to determine the relationship between mex3a and bladder urothelial carcinoma. Methods The clinical and RNA sequencing expression data in patients with bladder urothelial carcinoma were downloaded from the The Cancer Genome Atlas data portal. A total of 412 bladder urothelial carcinoma samples were available in the database, for which the clinical information was acquired, of which 412 are RNA sequencing samples with a total of 19 paired samples. Univariate and multivariate Cox analyses and univariate logistic regression analysis were conducted using the software SPSS version 22.0 and P<0.05 was considered statistically significant. Results The results of the independent t-test of 19 paired samples indicated that the expression level of mex3a was significantly higher in tumor tissues compared with adjacent normal tissues. Mex3a expression as a categorical dependent variable was not associated with overall survival, and the overall survival of bladder urothelial carcinoma was associated with the group of age, cancer status, lymphatic vascular invasion, pathological stage, pathological size, and pathological lymph metastasis. The multivariable Cox model adjusted for the group of mex3a expression level, age, gender, tumor status, and pathological stage showed that only the age and cancer status groups were associated with the overall survival. Conclusion Mex3a expression was not a poor prognostic factor of bladder urothelial carcinoma. Moreover, the expression levels of mex3a in the papillary type of bladder urothelial carcinoma were higher than those of the non-papillary type.
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Affiliation(s)
- Jing-Wen Shi
- Department of Ultrasound, Shengjing Hospital of China Medical University, 110004, Shenyang, China
| | - Ying Huang
- Department of Ultrasound, Shengjing Hospital of China Medical University, 110004, Shenyang, China
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39
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Subasic D, Stoeger T, Eisenring S, Matia-González AM, Imig J, Zheng X, Xiong L, Gisler P, Eberhard R, Holtackers R, Gerber AP, Pelkmans L, Hengartner MO. Post-transcriptional control of executioner caspases by RNA-binding proteins. Genes Dev 2017; 30:2213-2225. [PMID: 27798844 PMCID: PMC5088569 DOI: 10.1101/gad.285726.116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 09/16/2016] [Indexed: 12/03/2022]
Abstract
In this study, Subasic et al. investigated the post-transcriptional control of caspases. The authors describe four conserved RNA-binding proteins (RBPs) that sequentially repress the CED-3 caspase in distinct regions of the C. elegans germline and identify seven RBPs that regulate human caspase-3 expression and/or activation, suggesting that translational inhibition of executioner caspases by RBPs might be a general strategy used widely across the animal kingdom to control apoptosis. Caspases are key components of apoptotic pathways. Regulation of caspases occurs at several levels, including transcription, proteolytic processing, inhibition of enzymatic function, and protein degradation. In contrast, little is known about the extent of post-transcriptional control of caspases. Here, we describe four conserved RNA-binding proteins (RBPs)—PUF-8, MEX-3, GLD-1, and CGH-1—that sequentially repress the CED-3 caspase in distinct regions of the Caenorhabditis elegans germline. We demonstrate that GLD-1 represses ced-3 mRNA translation via two binding sites in its 3′ untranslated region (UTR), thereby ensuring a dual control of unwanted cell death: at the level of p53/CEP-1 and at the executioner caspase level. Moreover, we identified seven RBPs that regulate human caspase-3 expression and/or activation, including human PUF-8, GLD-1, and CGH-1 homologs PUM1, QKI, and DDX6. Given the presence of unusually long executioner caspase 3′ UTRs in many metazoans, translational control of executioner caspases by RBPs might be a strategy used widely across the animal kingdom to control apoptosis.
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Affiliation(s)
- Deni Subasic
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland.,Molecular Life Sciences PhD Program, Swiss Federal Institute of Technology, University of Zurich, 8057 Zurich, Switzerland
| | - Thomas Stoeger
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland.,Systems Biology PhD Program, Swiss Federal Institute of Technology, University of Zurich, 8057 Zurich, Switzerland
| | - Seline Eisenring
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Ana M Matia-González
- Faculty of Health and Medical Sciences, Department of Microbial and Cellular Sciences, University of Surrey, Stag Hill Campus, GU2 7XH Guildford, United Kingdom
| | - Jochen Imig
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Xue Zheng
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Lei Xiong
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Pascal Gisler
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Ralf Eberhard
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - René Holtackers
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - André P Gerber
- Faculty of Health and Medical Sciences, Department of Microbial and Cellular Sciences, University of Surrey, Stag Hill Campus, GU2 7XH Guildford, United Kingdom
| | - Lucas Pelkmans
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Michael O Hengartner
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
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LIN-41 and OMA Ribonucleoprotein Complexes Mediate a Translational Repression-to-Activation Switch Controlling Oocyte Meiotic Maturation and the Oocyte-to-Embryo Transition in Caenorhabditis elegans. Genetics 2017; 206:2007-2039. [PMID: 28576864 PMCID: PMC5560804 DOI: 10.1534/genetics.117.203174] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 05/31/2017] [Indexed: 11/30/2022] Open
Abstract
An extended meiotic prophase is a hallmark of oogenesis. Hormonal signaling activates the CDK1/cyclin B kinase to promote oocyte meiotic maturation, which involves nuclear and cytoplasmic events. Nuclear maturation encompasses nuclear envelope breakdown, meiotic spindle assembly, and chromosome segregation. Cytoplasmic maturation involves major changes in oocyte protein translation and cytoplasmic organelles and is poorly understood. In the nematode Caenorhabditis elegans, sperm release the major sperm protein (MSP) hormone to promote oocyte growth and meiotic maturation. Large translational regulatory ribonucleoprotein (RNP) complexes containing the RNA-binding proteins OMA-1, OMA-2, and LIN-41 regulate meiotic maturation downstream of MSP signaling. To understand the control of translation during meiotic maturation, we purified LIN-41-containing RNPs and characterized their protein and RNA components. Protein constituents of LIN-41 RNPs include essential RNA-binding proteins, the GLD-2 cytoplasmic poly(A) polymerase, the CCR4-NOT deadenylase complex, and translation initiation factors. RNA sequencing defined messenger RNAs (mRNAs) associated with both LIN-41 and OMA-1, as well as sets of mRNAs associated with either LIN-41 or OMA-1. Genetic and genomic evidence suggests that GLD-2, which is a component of LIN-41 RNPs, stimulates the efficient translation of many LIN-41-associated transcripts. We analyzed the translational regulation of two transcripts specifically associated with LIN-41 which encode the RNA regulators SPN-4 and MEG-1. We found that LIN-41 represses translation of spn-4 and meg-1, whereas OMA-1 and OMA-2 promote their expression. Upon their synthesis, SPN-4 and MEG-1 assemble into LIN-41 RNPs prior to their functions in the embryo. This study defines a translational repression-to-activation switch as a key element of cytoplasmic maturation.
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41
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Davis M, Montalbano A, Wood MP, Schisa JA. Biphasic adaptation to osmotic stress in the C. elegans germ line. Am J Physiol Cell Physiol 2017; 312:C741-C748. [PMID: 28381521 DOI: 10.1152/ajpcell.00364.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/20/2017] [Accepted: 04/03/2017] [Indexed: 12/21/2022]
Abstract
Cells respond to environmental stress in multiple ways. In the germ line, heat shock and nutritive stress trigger the assembly of large ribonucleoprotein (RNP) granules via liquid-liquid phase separation (LLPS). The RNP granules are hypothesized to maintain the quality of oocytes during stress. The goal of this study was to investigate the cellular response to glucose in the germ line and determine if it is an osmotic stress response. We found that exposure to 500 mM glucose induces the assembly of RNP granules in the germ line within 1 h. Interestingly, the RNP granules are maintained for up to 3 h; however, they dissociate after longer periods of stress. The RNP granules include processing body and stress granule proteins, suggesting shared functions. Based on several lines of evidence, the germ line response to glucose largely appears to be an osmotic stress response, thus identifying osmotic stress as a trigger of LLPS. Although RNP granules are not maintained beyond 3 h of osmotic stress, the quality of oocytes does not appear to decrease after longer periods of stress, suggesting a secondary adaptation in the germ line. We used an indirect marker of glycerol and observed high levels after 5 and 20 h of glucose exposure. Moreover, in gpdh-1;gpdh-2 germ lines, glycerol levels are reduced concomitant with RNP granules being maintained for an extended period. We speculate that increased glycerol levels may function as a secondary osmoregulatory adaptive response in the germ line, following a primary response of RNP granule assembly.
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Affiliation(s)
- Michael Davis
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan
| | - Andrea Montalbano
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan
| | - Megan P Wood
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan
| | - Jennifer A Schisa
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan
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Robertson SM, Medina J, Oldenbroek M, Lin R. Reciprocal signaling by Wnt and Notch specifies a muscle precursor in the C. elegans embryo. Development 2017; 144:419-429. [PMID: 28049659 DOI: 10.1242/dev.145391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 12/12/2016] [Indexed: 11/20/2022]
Abstract
The MS blastomere produces one-third of the body wall muscles (BWMs) in the C. elegans embryo. MS-derived BWMs require two distinct cell-cell interactions, the first inhibitory and the second, two cell cycles later, required to overcome this inhibition. The inductive interaction is not required if the inhibitory signal is absent. Although the Notch receptor GLP-1 was implicated in both interactions, the molecular nature of the two signals was unknown. We now show that zygotically expressed MOM-2 (Wnt) is responsible for both interactions. Both the inhibitory and the activating interactions require precise spatiotemporal expression of zygotic MOM-2, which is dependent upon two distinct Notch signals. In a Notch mutant defective only in the inductive interaction, MS-derived BWMs can be restored by preventing zygotic MOM-2 expression, which removes the inhibitory signal. Our results suggest that the inhibitory interaction ensures the differential lineage specification of MS and its sister blastomere, whereas the inductive interaction promotes the expression of muscle-specifying genes by modulating TCF and β-catenin levels. These results highlight the complexity of cell fate specification by cell-cell interactions in a rapidly dividing embryo.
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Affiliation(s)
- Scott M Robertson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jessica Medina
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Marieke Oldenbroek
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rueyling Lin
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Pushpa K, Kumar GA, Subramaniam K. Translational Control of Germ Cell Decisions. Results Probl Cell Differ 2017; 59:175-200. [PMID: 28247049 DOI: 10.1007/978-3-319-44820-6_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Germline poses unique challenges to gene expression control at the transcriptional level. While the embryonic germline maintains a global hold on new mRNA transcription, the female adult germline produces transcripts that are not translated into proteins until embryogenesis of subsequent generation. As a consequence, translational control plays a central role in governing various germ cell decisions including the formation of primordial germ cells, self-renewal/differentiation decisions in the adult germline, onset of gametogenesis and oocyte maturation. Mechanistically, several common themes such as asymmetric localization of mRNAs, conserved RNA-binding proteins that control translation by 3' UTR binding, translational activation by the cytoplasmic elongation of the polyA tail and the assembly of mRNA-protein complexes called mRNPs have emerged from the studies on Caenorhabditis elegans, Xenopus and Drosophila. How mRNPs assemble, what influences their dynamics, and how a particular 3' UTR-binding protein turns on the translation of certain mRNAs while turning off other mRNAs at the same time and space are key challenges for future work.
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Affiliation(s)
- Kumari Pushpa
- Regional Centre for Biotechnology, Faridabad, Haryana, India
| | - Ganga Anil Kumar
- Indian Institute of Technology-Kanpur, Kanpur, India.,Indian Institute of Technology-Madras, Chennai, India
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Kaymak E, Farley BM, Hay SA, Li C, Ho S, Hartman DJ, Ryder SP. Efficient generation of transgenic reporter strains and analysis of expression patterns in Caenorhabditis elegans using library MosSCI. Dev Dyn 2016; 245:925-36. [PMID: 27294288 PMCID: PMC4981527 DOI: 10.1002/dvdy.24426] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 05/09/2016] [Accepted: 06/03/2016] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND In C. elegans, germline development and early embryogenesis rely on posttranscriptional regulation of maternally transcribed mRNAs. In many cases, the 3' untranslated region (UTR) is sufficient to govern the expression patterns of these transcripts. Several RNA-binding proteins are required to regulate maternal mRNAs through the 3'UTR. Despite intensive efforts to map RNA-binding protein-mRNA interactions in vivo, the biological impact of most binding events remains unknown. Reporter studies using single copy integrated transgenes are essential to evaluate the functional consequences of interactions between RNA-binding proteins and their associated mRNAs. RESULTS In this report, we present an efficient method of generating reporter strains with improved throughput by using a library variant of MosSCI transgenesis. Furthermore, using RNA interference, we identify the suite of RNA-binding proteins that control the expression pattern of five different maternal mRNAs. CONCLUSIONS The results provide a generalizable and efficient strategy to assess the functional relevance of protein-RNA interactions in vivo, and reveal new regulatory connections between key RNA-binding proteins and their maternal mRNA targets. Developmental Dynamics 245:925-936, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ebru Kaymak
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Brian M. Farley
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
| | - Samantha A. Hay
- Virginia Commonwealth University School of Medicine, VA, USA
| | - Chihua Li
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Samantha Ho
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | | | - Sean P. Ryder
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
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RNAi Screen Identifies Novel Regulators of RNP Granules in the Caenorhabditis elegans Germ Line. G3-GENES GENOMES GENETICS 2016; 6:2643-54. [PMID: 27317775 PMCID: PMC4978917 DOI: 10.1534/g3.116.031559] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Complexes of RNA and RNA binding proteins form large-scale supramolecular structures under many cellular contexts. In Caenorhabditis elegans, small germ granules are present in the germ line that share characteristics with liquid droplets that undergo phase transitions. In meiotically-arrested oocytes of middle-aged hermaphrodites, the germ granules appear to aggregate or condense into large assemblies of RNA-binding proteins and maternal mRNAs. Prior characterization of the assembly of large-scale RNP structures via candidate approaches has identified a small number of regulators of phase transitions in the C. elegans germ line; however, the assembly, function, and regulation of these large RNP assemblies remain incompletely understood. To identify genes that promote remodeling and assembly of large RNP granules in meiotically-arrested oocytes, we performed a targeted, functional RNAi screen and identified over 300 genes that regulate the assembly of the RNA-binding protein MEX-3 into large granules. Among the most common GO classes are several categories related to RNA biology, as well as novel categories such as cell cortex, ER, and chromosome segregation. We found that arrested oocytes that fail to localize MEX-3 into cortical granules display reduced oocyte quality, consistent with the idea that the larger RNP assemblies promote oocyte quality when fertilization is delayed. Interestingly, a relatively small number of genes overlap with the regulators of germ granule assembly during normal development, or with the regulators of solid RNP granules in cgh-1 oocytes, suggesting fundamental differences in the regulation of RNP granule phase transitions during meiotic arrest.
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Shigunov P, Dallagiovanna B. Stem Cell Ribonomics: RNA-Binding Proteins and Gene Networks in Stem Cell Differentiation. Front Mol Biosci 2015; 2:74. [PMID: 26734617 PMCID: PMC4686646 DOI: 10.3389/fmolb.2015.00074] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 12/07/2015] [Indexed: 12/21/2022] Open
Abstract
Stem cells are undifferentiated cells with the ability to self-renew and the potential to differentiate into all body cell types. Stem cells follow a developmental genetic program and are able to respond to alterations in the environment through various signaling pathways. The mechanisms that control these processes involve the activation of transcription followed by a series of post-transcriptional events. These post-transcriptional steps are mediated by the interaction of RNA-binding proteins (RBPs) with defined subpopulations of RNAs creating a regulatory gene network. Characterizing these RNA-protein networks is essential to understanding the regulatory mechanisms underlying the control of stem cell fate. Ribonomics is the combination of classical biochemical purification protocols with the high-throughput identification of transcripts applied to the functional characterization of RNA-protein complexes. Here, we describe the different approaches that can be used in a ribonomic approach and how they have contributed to understanding the function of several RBPs with central roles in stem cell biology.
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Affiliation(s)
- Patrícia Shigunov
- Stem Cells Basic Biology Laboratory, Carlos Chagas Institute, Oswaldo Cruz Foundation Curitiba, Brazil
| | - Bruno Dallagiovanna
- Stem Cells Basic Biology Laboratory, Carlos Chagas Institute, Oswaldo Cruz Foundation Curitiba, Brazil
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Robert VJ, Garvis S, Palladino F. Repression of somatic cell fate in the germline. Cell Mol Life Sci 2015; 72:3599-620. [PMID: 26043973 PMCID: PMC11113910 DOI: 10.1007/s00018-015-1942-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/26/2015] [Accepted: 05/27/2015] [Indexed: 01/13/2023]
Abstract
Germ cells must transmit genetic information across generations, and produce gametes while also maintaining the potential to form all cell types after fertilization. Preventing the activation of somatic programs is, therefore, crucial to the maintenance of germ cell identity. Studies in Caenorhabditis elegans, Drosophila melanogaster, and mouse have revealed both similarities and differences in how somatic gene expression is repressed in germ cells, thereby preventing their conversion into somatic tissues. This review will focus on recent developments in our understanding of how global or gene-specific transcriptional repression, chromatin regulation, and translational repression operate in the germline to maintain germ cell identity and repress somatic differentiation programs.
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Affiliation(s)
- Valérie J Robert
- Ecole Normale Supérieure de Lyon, Université de Lyon, 46 allée d'Italie, 69007, Lyon, France
| | - Steve Garvis
- Ecole Normale Supérieure de Lyon, Université de Lyon, 46 allée d'Italie, 69007, Lyon, France
| | - Francesca Palladino
- Ecole Normale Supérieure de Lyon, Université de Lyon, 46 allée d'Italie, 69007, Lyon, France.
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Campbell AC, Updike DL. CSR-1 and P granules suppress sperm-specific transcription in the C. elegans germline. Development 2015; 142:1745-55. [PMID: 25968310 DOI: 10.1242/dev.121434] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Germ granules (P granules) in C. elegans are required for fertility and function to maintain germ cell identity and pluripotency. Sterility in the absence of P granules is often accompanied by the misexpression of soma-specific proteins and the initiation of somatic differentiation in germ cells. To investigate whether this is caused by the accumulation of somatic transcripts, we performed mRNA-seq on dissected germlines with and without P granules. Strikingly, we found that somatic transcripts do not increase in the young adult germline when P granules are impaired. Instead, we found that impairing P granules causes sperm-specific mRNAs to become highly overexpressed. This includes the accumulation of major sperm protein (MSP) transcripts in germ cells, a phenotype that is suppressed by feminization of the germline. A core component of P granules, the endo-siRNA-binding Argonaute protein CSR-1, has recently been ascribed with the ability to license transcripts for germline expression. However, impairing CSR-1 has very little effect on the accumulation of its mRNA targets. Instead, we found that CSR-1 functions with P granules to prevent MSP and sperm-specific mRNAs from being transcribed in the hermaphrodite germline. These findings suggest that P granules protect germline integrity through two different mechanisms, by (1) preventing the inappropriate expression of somatic proteins at the level of translational regulation, and by (2) functioning with CSR-1 to limit the domain of sperm-specific expression at the level of transcription.
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Affiliation(s)
- Anne C Campbell
- Kathryn W. Davis Center for Regenerative Biology and Medicine, Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
| | - Dustin L Updike
- Kathryn W. Davis Center for Regenerative Biology and Medicine, Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
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Wu Y, Zhang H, Griffin EE. Coupling between cytoplasmic concentration gradients through local control of protein mobility in the Caenorhabditis elegans zygote. Mol Biol Cell 2015; 26:2963-70. [PMID: 26157168 PMCID: PMC4551312 DOI: 10.1091/mbc.e15-05-0302] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 06/30/2015] [Indexed: 12/17/2022] Open
Abstract
Cell polarity is characterized by the asymmetric distribution of factors at the cell cortex and in the cytoplasm. Although mechanisms that establish cortical asymmetries have been characterized, less is known about how persistent cytoplasmic asymmetries are generated. During the asymmetric division of the Caenorhabditis elegans zygote, the PAR proteins orchestrate the segregation of the cytoplasmic RNA-binding proteins MEX-5/6 to the anterior cytoplasm and PIE-1, POS-1, and MEX-1 to the posterior cytoplasm. In this study, we find that MEX-5/6 control the segregation of GFP::PIE-1, GFP::POS-1, and GFP::MEX-1 by locally increasing their mobility in the anterior cytoplasm. Remarkably, PIE-1, POS-1, and MEX-1 form gradients with distinct strengths, which correlates with differences in their responsiveness to MEX-5/6. We show that MEX-5/6 act downstream of the polarity regulators PAR-1 and PAR-3 and in a concentration-dependent manner to increase the mobility of GFP::PIE-1. These findings suggest that the MEX-5/6 concentration gradients are directly coupled to the establishment of posterior-rich PIE-1, POS-1, and MEX-1 concentration gradients via the formation of anterior-fast, posterior-slow mobility gradients.
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Affiliation(s)
- Youjun Wu
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Huaiying Zhang
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Erik E Griffin
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
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50
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Zhu SJ, Hallows SE, Currie KW, Xu C, Pearson BJ. A mex3 homolog is required for differentiation during planarian stem cell lineage development. eLife 2015; 4. [PMID: 26114597 PMCID: PMC4507787 DOI: 10.7554/elife.07025] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 06/25/2015] [Indexed: 12/30/2022] Open
Abstract
Neoblasts are adult stem cells (ASCs) in planarians that sustain cell replacement during homeostasis and regeneration of any missing tissue. While numerous studies have examined genes underlying neoblast pluripotency, molecular pathways driving postmitotic fates remain poorly defined. In this study, we used transcriptional profiling of irradiation-sensitive and irradiation-insensitive cell populations and RNA interference (RNAi) functional screening to uncover markers and regulators of postmitotic progeny. We identified 32 new markers distinguishing two main epithelial progenitor populations and a planarian homolog to the MEX3 RNA-binding protein (Smed-mex3-1) as a key regulator of lineage progression. mex3-1 was required for generating differentiated cells of multiple lineages, while restricting the size of the stem cell compartment. We also demonstrated the utility of using mex3-1(RNAi) animals to identify additional progenitor markers. These results identified mex3-1 as a cell fate regulator, broadly required for differentiation, and suggest that mex3-1 helps to mediate the balance between ASC self-renewal and commitment. DOI:http://dx.doi.org/10.7554/eLife.07025.001 Adult tissues constantly replace the millions of cells they lose on a daily basis. This is made possible by adult stem cells. But how is a stable population of stem cells maintained throughout the life of the organism with constant cell division? One way this can be accomplished is if at every stem cell division, only one of the daughter cells remains a stem cell, while the other becomes specialized. For humans, if this balance is disturbed, cancers may result from too many stem cells, and early aging may result from too few stem cells. A freshwater flatworm called Schmidtea mediterranea is known for its ability to regenerate nearly every part of its body after injury. This flatworm possesses stem cells called neoblasts that can form all of the flatworm's different cell types both during regeneration and during normal tissue turnover. Evidence suggests that the number of neoblasts and the number of specialized cells that neoblasts produce are finely balanced, similar to adult human tissues. However, little is known about the mechanism that controls whether a neoblast takes on a more specialized form. To express a gene, it must first be copied or ‘transcribed’ into an RNA molecule. Identifying the RNA molecules that are enriched in the non-stem cells that develop from neoblasts could therefore indicate which genes regulate the cell specialization process. These RNA molecules could also be used as markers that identify which cells have taken on a more specialized form. Using techniques called transcriptional profiling and RNA interference, Zhu et al. identified 32 new markers that indicate that the neoblasts have started to specialize into epithelial cells: cells that line the surfaces of many structures in the body. Further investigation revealed that one gene, called mex3-1, is needed for many specialized cell types—not just epithelial cells—to mature from neoblasts in the flatworms. In doing so, mex3-1 also limits the size of the stem cell population. Equivalents of mex3-1 are found in many different species including humans, and so Zhu et al.'s results may help us to understand how other animals regenerate and control the size of their stem cell populations. Mutant flatworms that cannot express mex3-1 could also be used to study other genes that help neoblasts to specialize. DOI:http://dx.doi.org/10.7554/eLife.07025.002
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Affiliation(s)
- Shu Jun Zhu
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Canada
| | - Stephanie E Hallows
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Canada
| | - Ko W Currie
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Canada
| | - ChangJiang Xu
- Terrence Donnelly Centre for Cellular and Biomedical Research, Toronto, Canada
| | - Bret J Pearson
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Canada
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