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Kaku Y, Isono Y, Tanaka H, Kobayashi T, Kanemori Y, Kashiwabara SI. Intronless Pabpc6 encodes a testis-specific, cytoplasmic poly(A)-binding protein but is dispensable for spermatogenesis in the mouse†. Biol Reprod 2024; 110:834-847. [PMID: 38281153 DOI: 10.1093/biolre/ioae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 12/25/2023] [Accepted: 01/23/2024] [Indexed: 01/30/2024] Open
Abstract
Besides ubiquitous poly(A)-binding protein, cytoplasmic 1 (PABPC1), testis-specific PABPC2/PABPt (in humans, referred to as PABPC3), and female and male germline-specific PABPC1L/ePAB, have been reported in the mouse testis. Recent in silico analysis additionally identified testis-specific Pabpc6 in the mouse. In this study, we characterized PABPC6 and its mutant mice. PABPC6 was initially detectable in the cytoplasm of pachytene spermatocytes, increased in abundance in round spermatids, and decreased in elongating spermatids. PABPC6 was capable of binding to poly(A) tails of various mRNAs and interacting with translation-associated factors, including EIF4G, PAIP1, and PAIP2. Noteworthy was that PABPC6, unlike PABPC1, was barely associated with translationally active polysomes and enriched in chromatoid bodies of round spermatids. Despite these unique characteristics, neither synthesis of testicular proteins nor spermatogenesis was affected in the mutant mice lacking PABPC6, suggesting that PABPC6 is functionally redundant with other co-existing PABPC proteins during spermatogenesis.
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Affiliation(s)
- Yuko Kaku
- Institute of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yuka Isono
- Institute of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hideto Tanaka
- Institute of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Tomohiro Kobayashi
- Institute of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yoshinori Kanemori
- Institute of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Shin-Ichi Kashiwabara
- Institute of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
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2
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Okutman O, Gürbüz AS, Büyük U, Real E, Leconte R, Chennen K, Mayer C, Muller J, Le May N, Viville S. Pathogenic missense variation in PABPC1L/EPAB causes female infertility due to oocyte maturation arrest at the germinal vesicle stage. J Assist Reprod Genet 2024; 41:311-322. [PMID: 38177974 PMCID: PMC10894787 DOI: 10.1007/s10815-023-03009-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 12/13/2023] [Indexed: 01/06/2024] Open
Abstract
Women undergoing controlled ovarian hyperstimulation prior to in vitro fertilization (IVF) are treated using various protocols to induce multiple follicular growths. Complete failure of all oocytes to mature during IVF cycles is rare; however, it is a known cause of primary female infertility. Recently, pathogenic variations in a few genes have been identified in women with oocyte maturation defects; however, the underlying genetic causes remain largely unknown.This study included a Turkish family comprising three sisters with recurring oocyte maturation arrest at the germinal vesicle stage after multiple ovarian stimulations. Exome sequencing revealed a homozygous missense variant (c.1037C>T, p.Ala346Val) in the EPAB gene (also known as PABPC1L) in all three affected sisters, which was either absent or heterozygous in the unaffected family members. Functional experiments confirming the pathogenicity of the variant were performed by transfecting HEK293T cells and demonstrated the instability and increased rate of proteolysis of the mutated PABPC1L/EPAB protein. The identified variant, located in the well-conserved fourth RNA recognition motif (RRM4), in silico 3D modelling suggested changes in the physical properties of the pathogenic variant of PABPC1L/EPAB. Our findings validate PABPC1L/EPAB as an essential genetic contributor to the oocyte maturation process in humans and have direct implications for the genetic counselling of patients and their family members.
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Affiliation(s)
- O Okutman
- Université Libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (H.U.B), Hôpital Erasme, Service de Gynécologie-Obstetrique, Clinique de Fertilité, Route de Lennik, 808, 1070, Brussels, Belgium
| | | | - U Büyük
- Department of Molecular Biology and Genetics, Institute of Graduate Studies in Sciences, Istanbul University, Istanbul, Turkey
| | - E Real
- Laboratoire de Génétique Médicale LGM, Institut de Génétique Médicale d'Alsace IGMA, INSERM UMR 1112, Université de Strasbourg, Strasbourg, France
| | - R Leconte
- Laboratoire de Génétique Médicale LGM, Institut de Génétique Médicale d'Alsace IGMA, INSERM UMR 1112, Université de Strasbourg, Strasbourg, France
| | - K Chennen
- Complex Systems and Translational Bioinformatics, ICube UMR 7357, Université de Strasbourg, 67000, Strasbourg, France
| | - C Mayer
- Complex Systems and Translational Bioinformatics, ICube UMR 7357, Université de Strasbourg, 67000, Strasbourg, France
- UFR Sciences de La Vie, Université Paris Cité, 75013, Paris, France
| | - J Muller
- Laboratoire de Génétique Médicale LGM, Institut de Génétique Médicale d'Alsace IGMA, INSERM UMR 1112, Université de Strasbourg, Strasbourg, France
- Unité Fonctionnelle de Bioinformatique Médicale Appliquée Au Diagnostic (UF7363), Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - N Le May
- Laboratoire de Génétique Médicale LGM, Institut de Génétique Médicale d'Alsace IGMA, INSERM UMR 1112, Université de Strasbourg, Strasbourg, France
| | - S Viville
- Laboratoire de Génétique Médicale LGM, Institut de Génétique Médicale d'Alsace IGMA, INSERM UMR 1112, Université de Strasbourg, Strasbourg, France.
- Laboratoire de Diagnostic Génétique, Unité de Génétique de L'infertilité (UF3472), Hôpitaux Universitaires de Strasbourg, 67091, Strasbourg, France.
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3
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Wang W, Guo J, Shi J, Li Q, Chen B, Pan Z, Qu R, Fu J, Shi R, Xue X, Mu J, Zhang Z, Wu T, Wang W, Zhao L, Li Q, He L, Sun X, Sang Q, Lin G, Wang L. Bi-allelic pathogenic variants in PABPC1L cause oocyte maturation arrest and female infertility. EMBO Mol Med 2023:e17177. [PMID: 37052235 DOI: 10.15252/emmm.202217177] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/14/2023] Open
Abstract
Oocyte maturation arrest is one of the important causes of female infertility, but the genetic factors remain largely unknown. PABPC1L, a predominant poly(A)-binding protein in Xenopus, mouse, and human oocytes and early embryos prior to zygotic genome activation, plays a key role in translational activation of maternal mRNAs. Here, we identified compound heterozygous and homozygous variants in PABPC1L that are responsible for female infertility mainly characterized by oocyte maturation arrest in five individuals. In vitro studies demonstrated that these variants resulted in truncated proteins, reduced protein abundance, altered cytoplasmic localization, and reduced mRNA translational activation by affecting the binding of PABPC1L to mRNA. In vivo, three strains of Pabpc1l knock-in (KI) female mice were infertile. RNA-sequencing analysis showed abnormal activation of the Mos-MAPK pathway in the zygotes of KI mice. Finally, we activated this pathway in mouse zygotes by injecting human MOS mRNA, and this mimicked the phenotype of KI mice. Our findings reveal the important roles of PABPC1L in human oocyte maturation and add a genetic potential candidate gene to be screened for causes of infertility.
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Affiliation(s)
- Weijie Wang
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Jing Guo
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Juanzi Shi
- Reproductive Medicine Center, Shaanxi Maternal and Child Care Service Center, Xi'an, China
| | - Qun Li
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
- Human Phenome Institute, Fudan University, Shanghai, China
| | - Biaobang Chen
- NHC Key Lab of Reproduction Regulation (Shanghai Institute for Biomedical and Pharmaceutical Technologies), Fudan University, Shanghai, China
| | - Zhiqi Pan
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Ronggui Qu
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Jing Fu
- Shanghai Ji Ai Genetics and IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, Shanghai, China
| | - Rong Shi
- Reproductive Medicine Center, Shaanxi Maternal and Child Care Service Center, Xi'an, China
| | - Xia Xue
- Reproductive Medicine Center, Shaanxi Maternal and Child Care Service Center, Xi'an, China
| | - Jian Mu
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Zhihua Zhang
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Tianyu Wu
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Wenjing Wang
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Lin Zhao
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Qiaoli Li
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Lin He
- Bio-X Center, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoxi Sun
- Shanghai Ji Ai Genetics and IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, Shanghai, China
| | - Qing Sang
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Ge Lin
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Lei Wang
- Institute of Pediatrics, Children's Hospital of Fudan University, the Shanghai Key Laboratory of Medical Epigenetics, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
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4
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Ozturk S, Kosebent EG, Talibova G, Bilmez Y, Tire B, Can A. Embryonic poly(A)-binding protein interacts with translation-related proteins and undergoes phosphorylation on the serine, threonine, and tyrosine residues in the mouse oocytes and early embryos. J Assist Reprod Genet 2023; 40:929-941. [PMID: 36823316 PMCID: PMC10224904 DOI: 10.1007/s10815-023-02746-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 02/03/2023] [Indexed: 02/25/2023] Open
Abstract
Expression of the embryonic poly(A)-binding protein (EPAB) in frog, mouse, and human oocytes and early-stage embryos is maintained at high levels until embryonic genome activation (EGA) after which a significant decrease occurs in EPAB levels. Studies on the vertebrate oocytes and early embryos revealed that EPAB plays key roles in the translational regulation, stabilization, and protection of maternal mRNAs during oocyte maturation and early embryogenesis. However, it remains elusive whether EPAB interacts with other cellular proteins and undergoes phosphorylation to perform these roles. For this purpose, we identified a group of Epab-interacting proteins and its phosphorylation status in mouse germinal vesicle (GV)- and metaphase II (MII)-stage oocytes, and in 1-cell, 2-cell, and 4-cell preimplantation embryos. In the oocytes and early preimplantation embryos, Epab-interacting proteins were found to play roles in the translation and transcription processes, intracellular signaling and transport, maintenance of structural integrity, metabolism, posttranslational modifications, and chromatin remodeling. Moreover, we discovered that Epab undergoes phosphorylation on the serine, threonine, and tyrosine residues, which are localized in the RNA recognition motifs 2, 3, and 4 or C-terminal. Conclusively, these findings suggest that Epab not only functions in the translational control of maternal mRNAs through binding to their poly(A) tails but also participates in various cellular events through interacting with certain group proteins. Most likely, Epab undergoes a dynamic phosphorylation during the oocyte maturation and the early embryo development to carry out these functions.
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Affiliation(s)
- Saffet Ozturk
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, Antalya, 07070, Turkey.
| | - Esra Gozde Kosebent
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, Antalya, 07070, Turkey
| | - Gunel Talibova
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, Antalya, 07070, Turkey
| | - Yesim Bilmez
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, Antalya, 07070, Turkey
| | - Betul Tire
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, Antalya, 07070, Turkey
| | - Alp Can
- Department of Histology and Embryology, Ankara University School of Medicine, Ankara, 06410, Turkey
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5
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Heim A, Niedermeier ML, Stengel F, Mayer TU. The translation regulator Zar1l controls timing of meiosis in Xenopus oocytes. Development 2022; 149:278465. [DOI: 10.1242/dev.200900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 09/23/2022] [Indexed: 11/07/2022]
Abstract
ABSTRACT
Oocyte maturation and early embryo development occur in vertebrates in the near absence of transcription. Thus, sexual reproduction of vertebrates critically depends on the timely translation of mRNAs already stockpiled in the oocyte. Yet how translational activation of specific mRNAs is temporally coordinated is still incompletely understood. Here, we elucidate the function of Zar1l, a yet uncharacterized member of the Zar RNA-binding protein family, in Xenopus oocytes. Employing TRIM-Away, we demonstrate that loss of Zar1l accelerates hormone-induced meiotic resumption of Xenopus oocytes due to premature accumulation of the M-phase-promoting kinase cMos. We show that Zar1l is a constituent of a large ribonucleoparticle containing the translation repressor 4E-T and the central polyadenylation regulator CPEB1, and that it binds directly to the cMos mRNA. Partial, hormone-induced degradation of Zar1l liberates 4E-T from CPEB1, which weakens translational repression of mRNAs encoding cMos and likely additional M-phase-promoting factors. Thus, our study provides fundamental insights into the mechanisms that ensure temporally regulated translation of key cell cycle regulators during oocyte maturation, which is essential for sexual reproductivity.
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Affiliation(s)
- Andreas Heim
- University of Konstanz 1 Department of Biology , , 78457 Konstanz , Germany
| | - Marie L. Niedermeier
- University of Konstanz 1 Department of Biology , , 78457 Konstanz , Germany
- Konstanz Research School Chemical Biology, University of Konstanz 2 , 78457 Konstanz , Germany
| | - Florian Stengel
- University of Konstanz 1 Department of Biology , , 78457 Konstanz , Germany
- Konstanz Research School Chemical Biology, University of Konstanz 2 , 78457 Konstanz , Germany
| | - Thomas U. Mayer
- University of Konstanz 1 Department of Biology , , 78457 Konstanz , Germany
- Konstanz Research School Chemical Biology, University of Konstanz 2 , 78457 Konstanz , Germany
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6
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Xiang K, Bartel DP. The molecular basis of coupling between poly(A)-tail length and translational efficiency. eLife 2021; 10:66493. [PMID: 34213414 PMCID: PMC8253595 DOI: 10.7554/elife.66493] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/21/2021] [Indexed: 01/10/2023] Open
Abstract
In animal oocytes and early embryos, mRNA poly(A)-tail length strongly influences translational efficiency (TE), but later in development this coupling between tail length and TE disappears. Here, we elucidate how this coupling is first established and why it disappears. Overexpressing cytoplasmic poly(A)-binding protein (PABPC) in Xenopus oocytes specifically improved translation of short-tailed mRNAs, thereby diminishing coupling between tail length and TE. Thus, strong coupling requires limiting PABPC, implying that in coupled systems longer-tail mRNAs better compete for limiting PABPC. In addition to expressing excess PABPC, post-embryonic mammalian cell lines had two other properties that prevented strong coupling: terminal-uridylation-dependent destabilization of mRNAs lacking bound PABPC, and a regulatory regime wherein PABPC contributes minimally to TE. Thus, these results revealed three fundamental mechanistic requirements for coupling and defined the context-dependent functions for PABPC, which promotes TE but not mRNA stability in coupled systems and mRNA stability but not TE in uncoupled systems. Cells are microscopic biological factories that are constantly creating new proteins. To do so, a cell must first convert its master genetic blueprint, the DNA, into strands of messenger RNA or mRNA. These strands are subsequently translated to make proteins. Cells have two ways to adjust the number of proteins they generate so they do not produce too many or too few: by changing how many mRNA molecules are available for translation, and by regulating how efficiently they translate these mRNA molecules into proteins. In animals, both unfertilized eggs and early-stage embryos lack the ability to create or destroy mRNAs, and consequently cannot adjust the number of mRNA molecules available for translation. These cells can therefore only regulate how efficiently each mRNA is translated. They do this by changing the length of the so-called poly(A) tail at the end of each mRNA molecule, which is made up of a long stretch of repeating adenosine nucleotides. The mRNAs with longer poly(A) tails are translated more efficiently than those with shorter poly(A) tails. However, this difference disappears in older embryos, when both long and short poly(A) tails are translated with equal efficiency, and it is largely unknown why. To find out more, Xiang and Bartel studied frog eggs, and discovered that artificially raising levels of a protein that binds poly(A) tails, also known as PABPC, improved the translation of short-tailed mRNAs to create a situation in which both short- and long-tailed mRNAs were translated with near-equal efficiency. This suggested that short- and long-tailed mRNAs compete for limited amounts of the translation-enhancing PABPC, and that long-tailed mRNAs are better at it than short-tailed mRNAs. Further investigation revealed that eggs also had to establish the right conditions for PABPC to enhance translation and had to protect mRNAs not associated with PABPC from being destroyed before they could be translated. Overall, Xiang and Bartel found that in eggs and early embryos, PABPC and poly(A) tails enhanced the translation of mRNAs but did not influence their stability, whereas later in development, they enhanced mRNA stability but not translation. This research provides new insights into how protein production is controlled at different stages of animal development, from unfertilized eggs to older embryos. Understanding how this process is regulated during normal development is crucial for gaining insights into how it can become dysfunctional and cause disease. These findings may therefore have important implications for research into areas such as infertility, reproductive medicine and rare genetic diseases.
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Affiliation(s)
- Kehui Xiang
- Howard Hughes Medical Institute, Cambridge, United States.,Whitehead Institute for Biomedical Research, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - David P Bartel
- Howard Hughes Medical Institute, Cambridge, United States.,Whitehead Institute for Biomedical Research, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
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7
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Zhao LW, Fan HY. Revisiting poly(A)-binding proteins: Multifaceted regulators during gametogenesis and early embryogenesis. Bioessays 2021; 43:e2000335. [PMID: 33830517 DOI: 10.1002/bies.202000335] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 12/27/2022]
Abstract
Post-transcriptional regulation faces a distinctive challenge in gametes. Transcription is limited when the germ cells enter the division phase due to condensed chromatin, while gene expression during gamete maturation, fertilization, and early cleavage depends on existing mRNA post-transcriptional coordination. The dynamics of the 3'-poly(A) tail play crucial roles in defining mRNA fate. The 3'-poly(A) tail is covered with poly(A)-binding proteins (PABPs) that help to mediate mRNA metabolism and recent work has shed light on the number and function of germ cell-specific expressed PABPs. There are two structurally different PABP groups distinguished by their cytoplasmic and nuclear localization. Both lack catalytic activity but are coupled with various roles through their interaction with multifunctional partners during mRNA metabolism. Here, we present a synopsis of PABP function during gametogenesis and early embryogenesis and describe both conventional and current models of the functions and regulation of PABPs, with an emphasis on the physiological significance of how germ cell-specific PABPs potentially affect human fertility.
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Affiliation(s)
- Long-Wen Zhao
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Heng-Yu Fan
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China.,Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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8
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Esencan E, Kallen A, Zhang M, Seli E. Translational activation of maternally derived mRNAs in oocytes and early embryos and the role of embryonic poly(A) binding protein (EPAB). Biol Reprod 2020; 100:1147-1157. [PMID: 30806655 DOI: 10.1093/biolre/ioz034] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/23/2019] [Accepted: 02/23/2019] [Indexed: 12/20/2022] Open
Abstract
Transcription ceases upon stimulation of oocyte maturation and gene expression during oocyte maturation, fertilization, and early cleavage relies on translational activation of maternally derived mRNAs. Two key mechanisms that mediate translation of mRNAs in oocytes have been described in detail: cytoplasmic polyadenylation-dependent and -independent. Both of these mechanisms utilize specific protein complexes that interact with cis-acting sequences located on 3'-untranslated region (3'-UTR), and both involve embryonic poly(A) binding protein (EPAB), the predominant poly(A) binding protein during early development. While mechanistic details of these pathways have primarily been elucidated using the Xenopus model, their roles are conserved in mammals and targeted disruption of key regulators in mouse results in female infertility. Here, we provide a detailed account of the molecular mechanisms involved in translational activation during oocyte and early embryo development, and the role of EPAB in this process.
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Affiliation(s)
- Ecem Esencan
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
| | - Amanda Kallen
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
| | - Man Zhang
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
| | - Emre Seli
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
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9
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Kim B, Kim HM, Kang MK, Sohn DH, Han SJ. 5'-UTR and ORF elements, as well as the 3'-UTR regulate the translation of Cyclin. Biochem Biophys Res Commun 2020; 527:968-973. [PMID: 32439164 DOI: 10.1016/j.bbrc.2020.04.151] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 04/29/2020] [Indexed: 12/25/2022]
Abstract
Mammalian oocyte maturation is wholly dependent on the translation of accumulated maternal transcripts. Therefore, measuring the translation of specific genes, especially Ccnb1 and Ccnb2, which are key regulators of the oocyte cell cycle in mice, is essential to monitor oocyte cell cycle progression. For this purpose, almost all previous research has used a reporter construct containing the 3'-untranslated region (UTR) of Ccnb. It is based on the concept that the 3'-UTR is the main modulator of translation. Here, we investigated the expression pattern of Renilla luciferase (RL) reporters combining the 5'-UTR and/or open reading frame (ORF) as well as the 3'-UTR (RL-3', 5'-RL-3', RL-ORF-3', and 5'-RL-ORF-3') of Ccnb1 and Ccnb2 in somatic cells and mouse oocytes. The addition of the 5'-UTR and/or ORF of Ccnb altered the expression of the RL-3' reporter in HEK293T cells and mouse oocytes. The ORF tended to suppress RL expression, whereas the 5'-UTR enhanced the expression in most cases. The increased rate in expression was the highest when only the 3'-UTR of Ccnb1 (RL-3') was used, whereas the 5'-RL-ORF-3' reporter showed a relatively lower increase during oocyte maturation. For Ccnb2, the RL-ORF-3' reporter showed the largest increase, and other reporters exhibited a similar increase in expression during oocyte maturation. Results show that the expression of these genes is modulated not only by the 3'-UTR but also by the 5'-UTR and ORF. Therefore, special caution should be taken when using only the 3'-UTR to monitor the expression of specific genes.
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Affiliation(s)
- Boram Kim
- Department of Biological Science, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea
| | - Hye Min Kim
- Department of Biological Science, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea; Institute of Digital Anti-Aging Healthcare, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea
| | - Min Kook Kang
- Department of Biological Science, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea; Department of Research Center, Dong Nam Institute of Radiological and Medical Sciences, 40 Jwadong-gil, Gijang-gun, Busan, 46033, Republic of Korea
| | - Dong Hyun Sohn
- Department of Microbiology and Immunology, Pusan National University School of Medicine, Yangsan, Gyeongnam, 50612, Republic of Korea
| | - Seung Jin Han
- Department of Biological Science, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea; Institute of Digital Anti-Aging Healthcare, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea; Department of Biotechnology, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea; Institute of Basic Science, Inje University, 197 Inje-ro, Gimhae, Gyeongnam, 50834, Republic of Korea.
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10
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Filatov MA, Nikishin DA, Khramova YV, Semenova ML. The in vitro Analysis of Quality of Ovarian Follicle Culture Systems Using Time-Lapse Microscopy and Quantitative Real-Time PCR. J Reprod Infertil 2020; 21:94-106. [PMID: 32500012 PMCID: PMC7253941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The aim of ovarian follicle in vitro culture is to obtain mature oocytes. To evaluate the efficiency of in vitro culture system, the status of the cultured oocyte can be analyzed. METHODS The preantral ovarian follicles retrieved from 14-day-old C57Bl/6J mice were cultured in 3D alginate hydrogel. The status of oocytes obtained from mature (3 months old, group A) and immature (3 weeks old, group B) mice was compared to the status of oocytes retrieved from ovarian follicles cultured in vitro (Group C) using qRT-PCR analysis and time-lapse microscopy. In the qRT-PCR analysis, 8 samples for group A (80 oocytes), 8 samples for group B (80 oocytes), and 6 samples for group C (60 oocytes) were included. Time-lapse analysis was performed in group A (oocytes n=31), group B (n=45), and group C (n=21). Statistical analysis was done by Kruskal-Wallis and chi-square tests and differences were considered statistically significant if p<0,05. RESULTS The diameter of group C oocytes is lower in comparison to group A oocytes (67 μm vs. 75 μm, correspondingly). Groups B and C oocytes exhibited delayed meiosis in comparison to group A oocytes. Expression levels of six oocyte maturation genes (Ccnb, CDK1, Ccnh, Wee2, Mos and Epab) were evaluated using qRT-PCR analysis. Expression levels of Ccnh and Epab are lowered in group C oocytes compared to the expression levels of these genes in groups A and B oocytes (p< 0.05). CONCLUSION Oocytes obtained after ovarian follicles in vitro culture have reduced development competence, future fundamental changes of in vitro culture systems can be expected.
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Affiliation(s)
- Maxim Alexeevich Filatov
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia,Corresponding Author: Maxim Alexeevich Filatov, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia E-mail:
| | - Denis Alexandrovich Nikishin
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia, N.K. Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
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11
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Ozturk S. The translational functions of embryonic poly(A)‐binding protein during gametogenesis and early embryo development. Mol Reprod Dev 2019; 86:1548-1560. [DOI: 10.1002/mrd.23253] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 07/26/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Saffet Ozturk
- Department of Histology and EmbryologyAkdeniz University School of MedicineAntalya Turkey
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12
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Cragle CE, MacNicol MC, Byrum SD, Hardy LL, Mackintosh SG, Richardson WA, Gray NK, Childs GV, Tackett AJ, MacNicol AM. Musashi interaction with poly(A)-binding protein is required for activation of target mRNA translation. J Biol Chem 2019; 294:10969-10986. [PMID: 31152063 PMCID: PMC6635449 DOI: 10.1074/jbc.ra119.007220] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/09/2019] [Indexed: 12/21/2022] Open
Abstract
The Musashi family of mRNA translational regulators controls both physiological and pathological stem cell self-renewal primarily by repressing target mRNAs that promote differentiation. In response to differentiation cues, Musashi can switch from a repressor to an activator of target mRNA translation. However, the molecular events that distinguish Musashi-mediated translational activation from repression are not understood. We have previously reported that Musashi function is required for the maturation of Xenopus oocytes and specifically for translational activation of specific dormant maternal mRNAs. Here, we employed MS to identify cellular factors necessary for Musashi-dependent mRNA translational activation. We report that Musashi1 needs to associate with the embryonic poly(A)-binding protein (ePABP) or the canonical somatic cell poly(A)-binding protein PABPC1 for activation of Musashi target mRNA translation. Co-immunoprecipitation studies demonstrated an increased Musashi1 interaction with ePABP during oocyte maturation. Attenuation of endogenous ePABP activity severely compromised Musashi function, preventing downstream signaling and blocking oocyte maturation. Ectopic expression of either ePABP or PABPC1 restored Musashi-dependent mRNA translational activation and maturation of ePABP-attenuated oocytes. Consistent with these Xenopus findings, PABPC1 remained associated with Musashi under conditions of Musashi target mRNA de-repression and translation during mammalian stem cell differentiation. Because association of Musashi1 with poly(A)-binding proteins has previously been implicated only in repression of Musashi target mRNAs, our findings reveal novel context-dependent roles for the interaction of Musashi with poly(A)-binding protein family members in response to extracellular cues that control cell fate.
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Affiliation(s)
- Chad E Cragle
- Department of Neurobiology and Developmental Sciences
| | - Melanie C MacNicol
- Department of Neurobiology and Developmental Sciences,; Center for Translational Neuroscience
| | - Stephanie D Byrum
- Department of Biochemistry and Molecular Biology,; Arkansas Children's Research Institute
| | - Linda L Hardy
- Department of Neurobiology and Developmental Sciences
| | | | - William A Richardson
- MRC Centre for Reproductive Health, Queens Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, United Kingdom
| | - Nicola K Gray
- MRC Centre for Reproductive Health, Queens Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, United Kingdom
| | - Gwen V Childs
- Department of Neurobiology and Developmental Sciences,; Center for Translational Neuroscience
| | - Alan J Tackett
- Department of Biochemistry and Molecular Biology,; Arkansas Children's Research Institute
| | - Angus M MacNicol
- Department of Neurobiology and Developmental Sciences,; Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205 and.
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13
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Uysal F, Ozturk S. Embryonic poly(A)‐binding protein is differently expressed and interacts with the messenger RNAs in the mouse oocytes and early embryos. J Cell Biochem 2018; 120:4694-4709. [DOI: 10.1002/jcb.27759] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/06/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Fatma Uysal
- Department of Histology and Embryology Akdeniz University School of Medicine Antalya Turkey
- Department of Histology and Embryology Ankara University School of Medicine Ankara Turkey
| | - Saffet Ozturk
- Department of Histology and Embryology Akdeniz University School of Medicine Antalya Turkey
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14
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Ozturk S, Uysal F. Poly(A)-binding proteins are required for translational regulation in vertebrate oocytes and early embryos. Reprod Fertil Dev 2018; 29:1890-1901. [PMID: 28103468 DOI: 10.1071/rd16283] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 12/01/2016] [Indexed: 12/22/2022] Open
Abstract
Poly(A)-binding proteins (PABPs) function in the timely regulation of gene expression during oocyte maturation, fertilisation and early embryo development in vertebrates. To this end, PABPs bind to poly(A) tails or specific sequences of maternally stored mRNAs to protect them from degradation and to promote their translational activities. To date, two structurally different PABP groups have been identified: (1) cytoplasmic PABPs, including poly(A)-binding protein, cytoplasmic 1 (PABPC1), embryonic poly(A)-binding protein (EPAB), induced PABP and poly(A)-binding protein, cytoplasmic 3; and (2) nuclear PABPs, namely embryonic poly(A)-binding protein 2 and nuclear poly(A)-binding protein 1. Many studies have been undertaken to characterise the spatial and temporal expression patterns and subcellular localisations of PABPC1 and EPAB in vertebrate oocytes and early embryos. In the present review, we comprehensively evaluate and discuss the expression patterns and particular functions of the EPAB and PABPC1 genes, especially in mouse and human oocytes and early embryos.
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Affiliation(s)
- Saffet Ozturk
- Department of Histology and Embryology, Akdeniz University, School of Medicine, Campus, 07070, Antalya, Turkey
| | - Fatma Uysal
- Department of Histology and Embryology, Akdeniz University, School of Medicine, Campus, 07070, Antalya, Turkey
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15
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Ozturk S, Uysal F. Potential roles of the poly(A)-binding proteins in translational regulation during spermatogenesis. J Reprod Dev 2018; 64:289-296. [PMID: 29780056 PMCID: PMC6105736 DOI: 10.1262/jrd.2018-026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Spermatogenesis is briefly defined as the production of mature spermatozoa from spermatogonial stem cells at the end of a strictly regulated process. It is well known that, to a large
extent, transcriptional activity ceases at mid-spermiogenesis. Several mRNAs transcribed during early stages of spermatogenesis are stored as ribonucleoproteins (RNPs). During the later
stages, translational control of these mRNAs is mainly carried out in a time dependent-manner by poly(A)-binding proteins (PABPs) in cooperation with other RNA-binding proteins and
translation-related factors. Conserved PABPs specifically bind to poly(A) tails at the 3′ ends of mRNAs to regulate their translational activity in spermatogenic cells. Studies in this field
have revealed that PABPs, particularly poly(A)-binding protein cytoplasmic 1 (Pabpc1), Pabpc2, and the embryonic poly(A)-binding protein (Epab), play roles in the translational regulation of
mRNAs required at later stages of spermatogenesis. In this review article, we evaluated the spatial and temporal expression patterns and potential functions of these PABPs in spermatogenic
cells during spermatogenesis. The probable relationship between alterations in PABP expression and the development of male infertility is also reviewed.
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Affiliation(s)
- Saffet Ozturk
- Department of Histology and Embryology, Akdeniz University, School of Medicine, Antalya, Turkey
| | - Fatma Uysal
- Department of Histology and Embryology, Akdeniz University, School of Medicine, Antalya, Turkey
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Molecular Mechanisms of Prophase I Meiotic Arrest Maintenance and Meiotic Resumption in Mammalian Oocytes. Reprod Sci 2018; 26:1519-1537. [DOI: 10.1177/1933719118765974] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mechanisms of meiotic prophase I arrest maintenance (germinal vesicle [GV] stage) and meiotic resumption (germinal vesicle breakdown [GVBD] stage) in mammalian oocytes seem to be very complicated. These processes are regulated via multiple molecular cascades at transcriptional, translational, and posttranslational levels, and many of them are interrelated. There are many molecular cascades of meiosis maintaining and meiotic resumption in oocyte which are orchestrated by multiple molecules produced by pituitary gland and follicular cells. Furthermore, many of these molecular cascades are duplicated, thus ensuring the stability of the entire system. Understanding mechanisms of oocyte maturation is essential to assess the oocyte status, develop effective protocols of oocyte in vitro maturation, and design novel contraceptive drugs. Mechanisms of meiotic arrest maintenance at prophase I and meiotic resumption in mammalian oocytes are covered in the present article.
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17
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Lowther KM, Favero F, Yang CR, Taylor HS, Seli E. Embryonic poly(A)-binding protein is required at the preantral stage of mouse folliculogenesis for oocyte-somatic communication. Biol Reprod 2017; 96:341-351. [PMID: 28203794 DOI: 10.1095/biolreprod.116.141234] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 11/18/2016] [Accepted: 12/12/2016] [Indexed: 12/16/2023] Open
Abstract
Embryonic poly(A)-binding protein (EPAB)-deficient mice are infertile due to defects in both the oocyte and the somatic cells of the ovary. Since EPAB is oocyte specific, the abnormalities in the somatic compartment of Epab−/− mice are likely due to factors inherent to the oocyte. Herein, we investigated whether oocyte–somatic communication is disrupted as a result of EPAB deficiency. We found that gap junctions are disrupted at the late preantral stage of folliculogenesis in Epab−/– mice and remain disrupted in cumulus-enclosed oocytes (COCs) from antral follicles. Consistent with the timing of gap junction dysfunction, F-actin staining of transzonal processes (TZPs) is lower in Epab−/− follicles at the late preantral stage and completely absent in Epab−/− COCs. Epab−/− oocytes express significantly lower levels of the junction protein E-cadherin, which is likely to be a contributing factor leading to premature TZP retraction. Overall, these results demonstrate that EPAB is important for oocyte–somatic communication by maintaining TZPs and gap junctions at the preantral stage of folliculogenesis.
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Affiliation(s)
- Katie M Lowther
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
| | - Federico Favero
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
| | - Cai-Rong Yang
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Sichuan, China
- Key Laboratory of Crop Genetic Resources and Improvement, Ministry of Education, Sichuan Agricultural University, Wenjiang, Sichuan, China
| | - Hugh S Taylor
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
| | - Emre Seli
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
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18
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Ozturk S, Sozen B, Uysal F, Bassorgun IC, Usta MF, Akkoyunlu G, Demir N. The poly(A)-binding protein genes, EPAB, PABPC1, and PABPC3 are differentially expressed in infertile men with non-obstructive azoospermia. J Assist Reprod Genet 2016; 33:335-348. [PMID: 26843391 DOI: 10.1007/s10815-016-0654-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 01/04/2016] [Indexed: 11/27/2022] Open
Abstract
PURPOSE Azoospermia is one of the major causes of male infertility and is basically classified into obstructive (OA) and non-obstructive azoospermia (NOA). The molecular background of NOA still largely remains elusive. It has been shown that the poly(A)-binding proteins (PABPs) essentially play critical roles in stabilization and translational control of the mRNAs during spermatogenesis. METHODS In the present study, we aim to evaluate expression levels of the PABP genes, EPAB, PABPC1, and PABPC3, in the testicular biopsy samples and in the isolated spermatocyte (SC) and round spermatid (RS) fractions obtained from men with various types of NOA including hypospermatogenesis (hyposperm), RS arrest, SC arrest, and Sertoli cell-only syndrome (SCO). RESULTS In the testicular biopsy samples, both PABPC1 and PABPC3 mRNA expressions were gradually decreased from hyposperm to SCO groups (P < 0.05), whereas there was no remarkable difference for the EPAB expression among groups. The expression levels of cytoplasmically localized PABPC1 and PABPC3 proteins dramatically reduced from hyposperm to SCO groups (P < 0.05). In the isolated SC and RS fractions, the EPAB, PABPC1, and PABPC3 mRNA expressions were gradually decreased from hyposperm to SC arrest groups (P < 0.05). Similarly, both PABPC1 and PABPC3 proteins were expressed at higher levels in the SC and RS fractions from hyposperm group when compared to the SC and RS fractions from either RS arrest or SC arrest group (P < 0.05). CONCLUSION Our findings suggest that observed significant alterations in the PABPs expression may have an implication for development of different NOA forms.
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Affiliation(s)
- Saffet Ozturk
- Department of Histology and Embryology, Akdeniz University, School of Medicine, Campus, 07070, Antalya, Turkey
| | - Berna Sozen
- Department of Histology and Embryology, Akdeniz University, School of Medicine, Campus, 07070, Antalya, Turkey
| | - Fatma Uysal
- Department of Histology and Embryology, Akdeniz University, School of Medicine, Campus, 07070, Antalya, Turkey
| | - Ibrahim C Bassorgun
- Department of Pathology, Akdeniz University, School of Medicine, Campus, 07070, Antalya, Turkey
| | - Mustafa F Usta
- Department of Urology, Akdeniz University, School of Medicine, Campus, 07070, Antalya, Turkey
| | - Gokhan Akkoyunlu
- Department of Histology and Embryology, Akdeniz University, School of Medicine, Campus, 07070, Antalya, Turkey
| | - Necdet Demir
- Department of Histology and Embryology, Akdeniz University, School of Medicine, Campus, 07070, Antalya, Turkey.
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19
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Yang CR, Lowther KM, Lalioti MD, Seli E. Embryonic Poly(A)-Binding Protein (EPAB) Is Required for Granulosa Cell EGF Signaling and Cumulus Expansion in Female Mice. Endocrinology 2016; 157:405-16. [PMID: 26492470 PMCID: PMC4701890 DOI: 10.1210/en.2015-1135] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Embryonic poly(A)-binding protein (EPAB) is the predominant poly(A)-binding protein in Xenopus, mouse, and human oocytes and early embryos before zygotic genome activation. EPAB is required for translational activation of maternally stored mRNAs in the oocyte and Epab(-/-) female mice are infertile due to impaired oocyte maturation, cumulus expansion, and ovulation. The aim of this study was to characterize the mechanism of follicular somatic cell dysfunction in Epab(-/-) mice. Using a coculture system of oocytectomized cumulus oophorus complexes (OOXs) with denuded oocytes, we found that when wild-type OOXs were cocultured with Epab(-/-) oocytes, or when Epab(-/-) OOXs were cocultured with WT oocytes, cumulus expansion failed to occur in response to epidermal growth factor (EGF). This finding suggests that oocytes and cumulus cells (CCs) from Epab(-/-) mice fail to send and receive the necessary signals required for cumulus expansion. The abnormalities in Epab(-/-) CCs are not due to lower expression of the oocyte-derived factors growth differentiation factor 9 or bone morphogenetic protein 15, because Epab(-/-) oocytes express these proteins at comparable levels with WT. Epab(-/-) granulosa cells (GCs) exhibit decreased levels of phosphorylated MEK1/2, ERK1/2, and p90 ribosomal S6 kinase in response to lutenizing hormone and EGF treatment, as well as decreased phosphorylation of the EGF receptor. In conclusion, EPAB, which is oocyte specific, is required for the ability of CCs and GCs to become responsive to LH and EGF signaling. These results emphasize the importance of oocyte-somatic communication for GC and CC function.
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Affiliation(s)
- Cai-Rong Yang
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut 06510
| | - Katie M Lowther
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut 06510
| | - Maria D Lalioti
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut 06510
| | - Emre Seli
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut 06510
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20
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Reyes JM, Ross PJ. Cytoplasmic polyadenylation in mammalian oocyte maturation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 7:71-89. [PMID: 26596258 DOI: 10.1002/wrna.1316] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 10/02/2015] [Accepted: 10/07/2015] [Indexed: 12/21/2022]
Abstract
Oocyte developmental competence is the ability of the mature oocyte to be fertilized and subsequently drive early embryo development. Developmental competence is acquired by completion of oocyte maturation, a process that includes nuclear (meiotic) and cytoplasmic (molecular) changes. Given that maturing oocytes are transcriptionally quiescent (as are early embryos), they depend on post-transcriptional regulation of stored transcripts for protein synthesis, which is largely mediated by translational repression and deadenylation of transcripts within the cytoplasm, followed by recruitment of specific transcripts in a spatiotemporal manner for translation during oocyte maturation and early development. Motifs within the 3' untranslated region (UTR) of messenger RNA (mRNA) are thought to mediate repression and downstream activation by their association with binding partners that form dynamic protein complexes that elicit differing effects on translation depending on cell stage and interacting proteins. The cytoplasmic polyadenylation (CP) element, Pumilio binding element, and hexanucleotide polyadenylation signal are among the best understood motifs involved in CP, and translational regulation of stored transcripts as their binding partners have been relatively well-characterized. Knowledge of CP in mammalian oocytes is discussed as well as novel approaches that can be used to enhance our understanding of the functional and contributing features to transcript CP and translational regulation during mammalian oocyte maturation. WIREs RNA 2016, 7:71-89. doi: 10.1002/wrna.1316 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Juan M Reyes
- Department of Animal Science, University of California, Davis, CA, USA
| | - Pablo J Ross
- Department of Animal Science, University of California, Davis, CA, USA
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Lowther KM, Mehlmann LM. Embryonic Poly(A)-Binding Protein Is Required During Early Stages of Mouse Oocyte Development for Chromatin Organization, Transcriptional Silencing, and Meiotic Competence. Biol Reprod 2015; 93:43. [PMID: 26134869 DOI: 10.1095/biolreprod.115.131359] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 06/19/2015] [Indexed: 01/02/2023] Open
Abstract
During oocyte maturation, fertilization, and early embryo development until zygotic genome activation (ZGA), transcription is suppressed, and gene expression is dependent upon the timely activation of stored mRNAs. Embryonic poly(A)-binding protein (EPAB) is the predominant poly(A)-binding protein in Xenopus, mouse, and human oocytes and early embryos and is important for regulating translational activation of maternally stored mRNAs. EPAB is critical for early development because Epab(-/-) female mice do not produce mature eggs and are infertile. In this study, we further characterize morphological and molecular aspects of Epab(-/-) oocytes. We demonstrated that Epab(-/-) oocytes are smaller in size, contain peripheral germinal vesicles, and are loosely associated with cumulus cells. The chromatin reorganization of the surrounded nucleolus (SN) configuration and transcriptional silencing that normally occurs during oocyte growth does not occur in Epab(-/-) oocytes. Interestingly, microinjection of Epab mRNA into Epab(-/-) preantral follicle-enclosed oocytes rescues reorganization of chromatin and oocyte maturation to metaphase II. Overall, these results demonstrate an important role for EPAB during oocyte growth and the acquisition of meiotic competence.
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Affiliation(s)
- Katie M Lowther
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut
| | - Lisa M Mehlmann
- Department of Cell Biology, University of Connecticut Health, Farmington, Connecticut
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Abstract
PABPs [poly(A)-binding proteins] bind to the poly(A) tail of eukaryotic mRNAs and are conserved in species ranging from yeast to human. The prototypical cytoplasmic member, PABP1, is a multifunctional RNA-binding protein with roles in global and mRNA-specific translation and stability, consistent with a function as a central regulator of mRNA fate in the cytoplasm. More limited insight into the molecular functions of other family members is available. However, the consequences of disrupting PABP function in whole organisms is less clear, particularly in vertebrates, and even more so in mammals. In the present review, we discuss current and emerging knowledge with respect to the functions of PABP family members in whole animal studies which, although incomplete, already underlines their biological importance and highlights the need for further intensive research in this area.
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Ozturk S, Sozen B, Demir N. Epab and Pabpc1 are differentially expressed in the postnatal mouse ovaries. J Assist Reprod Genet 2014; 32:137-46. [PMID: 25370180 DOI: 10.1007/s10815-014-0362-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 09/29/2014] [Indexed: 12/31/2022] Open
Abstract
PURPOSE Embryonic poly(A)-binding protein (EPAB) and poly(A)-binding protein, cytoplasmic 1 (PABPC1) bind poly(A) tails of mRNAs and mediate their translational regulation in germ cells and early preimplantation embryos. Although expression patterns and possible functions of the Epab and Pabpc1 genes have been examined in vertebrate germ cells and early embryos, their expression levels and cellular localizations in the postnatal mouse ovaries remained elusive. METHODS In the present study, we first aimed to characterize expression levels of the Epab and Pabpc1 genes in the prepubertal (1-, 2-, and 3-week old), pubertal (4-, 5-, and 6-week old), postpubertal (16-week and 18-week old), and aged (52-, 60-, and 72-week old) mouse ovaries by using quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS Epab mRNA was predominantly expressed in the prepubertal ovaries when compared to later developmental periods. However, Pabpc1 transcript was highly generated in the prepubertal and pubertal mouse ovaries except for 1-week old ovary than those of other developmental terms. In the prepubertal mouse ovaries, RNA in situ hybridization localized both Epab and Pabpc1 transcripts in the cytoplasm of oocytes and granulosa cells of all follicular stages. Consistently, Epab and Pabpc1 gene expression were detected in the cumulus cells and MII oocytes obtained from cumulus oocyte complexes (COCs). Ovarian follicle counting in the postnatal ovaries revealed that total number of follicles was higher in the prepubertal ovaries in comparison with later stages of development. CONCLUSION As a result, Epab and Pabpc1 expression exhibit differences at postnatal ovary development stages and both genes are transcribed in the granulosa cells and oocytes. These findings suggest that EPAB may predominantly play roles in translational regulation of the mRNAs during early oogenesis and folliculogenesis, but PABPC1 most likely perform these roles in the later terms of ovarian development along with EPAB protein.
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Affiliation(s)
- Saffet Ozturk
- Department of Histology and Embryology, School of Medicine, Akdeniz University, Campus, 07070, Antalya, Turkey
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Guzeloglu-Kayisli O, Lalioti MD, Babayev E, Torrealday S, Karakaya C, Seli E. Human embryonic poly(A)-binding protein (EPAB) alternative splicing is differentially regulated in human oocytes and embryos. Mol Hum Reprod 2013; 20:59-65. [PMID: 24002949 DOI: 10.1093/molehr/gat061] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Oocyte maturation is associated with suppression of transcriptional activity. Consequently, gene expression during oocyte maturation, fertilization and early embryo development, until zygotic genome activation (ZGA) is primarily regulated by translational activation of maternally derived mRNAs. Embryonic poly(A)-binding protein (EPAB) is the predominant poly(A)-binding protein in Xenopus, mouse and human oocytes and early embryos prior to ZGA. EPAB plays a key role in polyadenylation-dependent translational activation of mRNAs by stabilizing polyadenylated mRNAs and by stimulating their translation. Epab-knockout female mice are sterile, fail to generate mature oocytes and display impaired cumulus expansion and ovulation. Consistent with its role during gametogenesis and early embryo development, Xenopus and mouse Epab mRNA is expressed exclusively in oocytes and early embryos, and is undetectable following ZGA or in somatic tissues. Herein, we demonstrate that although EPAB is expressed in human somatic tissues, its transcripts largely consist of an alternatively spliced form lacking the first 58 bp of exon 8, which leads to the formation of a premature stop codon 6 amino acids downstream on exon 8, and omission of the functionally critical poly(A)-binding domain. Moreover, 8-cell and blastocyst stage human embryos also express only the alternatively spliced form of EPAB. On the other hand, the full-length form of EPAB mRNA is exclusively expressed in oocytes. In conclusion, in contrast with the transcriptional regulation in Xenopus and mouse, oocyte- and early embryo-specific expression of EPAB in human is regulated by a post-transcriptional mechanism.
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Affiliation(s)
- Ozlem Guzeloglu-Kayisli
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, 310 Cedar Street, LSOG 304B, New Haven, CT 06520-8063, USA
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Goss DJ, Kleiman FE. Poly(A) binding proteins: are they all created equal? WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 4:167-79. [PMID: 23424172 DOI: 10.1002/wrna.1151] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The PABP family of proteins were originally thought of as a simple shield for the mRNA poly(A) tail. Years of research have shown that PABPs interact not only with the poly(A) tail, but also with specific sequences in the mRNA, having a general and specific role on the metabolism of different mRNAs. The complexity of PABPs function is increased by the interactions of PABPs with factors involved in different cellular functions. PABPs participate in all the metabolic pathways of the mRNA: polyadenylation/deadenylation, mRNA export, mRNA surveillance, translation, mRNA degradation, microRNA-associated regulation, and regulation of expression during development. In this review, we update information on the roles of PABPs and emerging data on the specific interactions of PABP homologs. Specific functions of individual members of PABPC family in development and viral infection are beginning to be elucidated. However, the interactions are complex and recent evidence for exchange of nuclear and cytoplasmic forms of the proteins, as well as post-translational modifications, emphasize the possibilities for fine-tuning the PABP metabolic network.
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Affiliation(s)
- Dixie J Goss
- Chemistry Department, Hunter College CUNY, New York, NY, USA.
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Abstract
The function of cytoplasmic PABPs [poly(A)-binding proteins] in promoting mRNA translation has been intensively studied. However, PABPs also have less clearly defined functions in mRNA turnover including roles in default deadenylation, a major rate-limiting step in mRNA decay, as well as roles in the regulation of mRNA turnover by cis-acting control elements and in the detection of aberrant mRNA transcripts. In the present paper, we review our current understanding of the complex roles of PABP1 in mRNA turnover, focusing on recent progress in mammals and highlighting some of the major questions that remain to be addressed.
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Embryonic poly(A)-binding protein (EPAB) is required for oocyte maturation and female fertility in mice. Biochem J 2012; 446:47-58. [PMID: 22621333 DOI: 10.1042/bj20120467] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Gene expression during oocyte maturation and early embryogenesis up to zygotic genome activation requires translational activation of maternally-derived mRNAs. EPAB [embryonic poly(A)-binding protein] is the predominant poly(A)-binding protein during this period in Xenopus, mouse and human. In Xenopus oocytes, ePAB stabilizes maternal mRNAs and promotes their translation. To assess the role of EPAB in mammalian reproduction, we generated Epab-knockout mice. Although Epab(-/-) males and Epab(+/-) of both sexes were fertile, Epab(-/-) female mice were infertile, and could not generate embryos or mature oocytes in vivo or in vitro. Epab(-/-) oocytes failed to achieve translational activation of maternally-stored mRNAs upon stimulation of oocyte maturation, including Ccnb1 (cyclin B1) and Dazl (deleted in azoospermia-like) mRNAs. Microinjection of Epab mRNA into Epab(-/-) germinal vesicle stage oocytes did not rescue maturation, suggesting that EPAB is also required for earlier stages of oogenesis. In addition, late antral follicles in the ovaries of Epab(-/-) mice exhibited impaired cumulus expansion, and a 8-fold decrease in ovulation, associated with a significant down-regulation of mRNAs encoding the EGF (epidermal growth factor)-like growth factors Areg (amphiregulin), Ereg (epiregulin) and Btc (betacellulin), and their downstream regulators, Ptgs2 (prostaglandin synthase 2), Has2 (hyaluronan synthase 2) and Tnfaip6 (tumour necrosis factor α-induced protein 6). The findings from the present study indicate that EPAB is necessary for oogenesis, folliculogenesis and female fertility in mice.
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Burgess HM, Gray NK. An integrated model for the nucleo-cytoplasmic transport of cytoplasmic poly(A)-binding proteins. Commun Integr Biol 2012; 5:243-7. [PMID: 22896784 PMCID: PMC3419106 DOI: 10.4161/cib.19347] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cytoplasmic poly(A)-binding proteins (PABPs) regulate mRNA stability and translation. Although predominantly localized in the cytoplasm, PABP proteins also cycle through the nucleus. Recent work has established that their steady-state localization can be altered by cellular stresses such as ultraviolet (UV) radiation, and infection by several viruses, resulting in nuclear accumulation of PABPs. Here, we present further evidence that their interaction with and release from mRNA and translation complexes are important in determining their sub-cellular distribution and propose an integrated model for regulated nucleo-cytoplasmic transport of PABPs.
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Embryonic poly(A)-binding protein (ePAB) phosphorylation is required for Xenopus oocyte maturation. Biochem J 2012; 445:93-100. [PMID: 22497250 DOI: 10.1042/bj20120304] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Oocyte maturation and early embryonic development require the cytoplasmic polyadenylation and concomitant translational activation of stored maternal mRNAs. ePAB [embryonic poly(A)-binding protein, also known as ePABP and PABPc1-like] is a multifunctional post-transcriptional regulator that binds to poly(A) tails. In the present study we find that ePAB is a dynamically modified phosphoprotein in Xenopus laevis oocytes and show by mutation that phosphorylation at a four residue cluster is required for oocyte maturation. We further demonstrate that these phosphorylations are critical for cytoplasmic polyadenylation, but not for ePAB's inherent ability to promote translation. Our results provide the first insight into the role of post-translational modifications in regulating PABP protein activity in vivo.
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Smith RW, Anderson RC, Smith JW, Brook M, Richardson WA, Gray NK. DAZAP1, an RNA-binding protein required for development and spermatogenesis, can regulate mRNA translation. RNA (NEW YORK, N.Y.) 2011; 17:1282-95. [PMID: 21576381 PMCID: PMC3138565 DOI: 10.1261/rna.2717711] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Accepted: 04/01/2011] [Indexed: 05/30/2023]
Abstract
DAZ-associated protein 1 (DAZAP1) is an RNA-binding protein required for normal growth, development, and fertility in mice. However, its molecular functions have not been elucidated. Here we find that Xenopus laevis and human DAZAP1, which are each expressed as short and long forms, act as mRNA-specific activators of translation in a manner that is sensitive to the number of binding sites present within the 3' UTR. Domain mapping suggests that this conserved function is mainly associated with C-terminal regions of DAZAP1. Interestingly, we find that the expression of xDAZAP1 and its polysome association are developmentally controlled, the latter suggesting that the translational activator function of DAZAP1 is regulated. However, ERK phosphorylation of DAZAP1, which can alter protein interactions with its C terminus, does not play a role in regulating its ability to participate in translational complexes. Since relatively few mRNA-specific activators have been identified, we explored the mechanism by which DAZAP1 activates translation. By utilizing reporter mRNAs with internal ribosome entry sites, we establish that DAZAP1 stimulates translation initiation. Importantly, this activity is not dependent on the recognition of the 5' cap by initiation factors, showing that it functions downstream from this frequently regulated event, but is modulated by changes in the adenylation status of mRNAs. This suggests a function in the formation of "end-to-end" complexes, which are important for efficient initiation, which we show to be independent of a direct interaction with the bridging protein eIF4G.
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Affiliation(s)
- Richard W.P. Smith
- MRC Centre for Reproductive Health/MRC Human Reproductive Sciences Unit, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, United Kingdom
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh EH4 2XU, Scotland, United Kingdom
| | - Ross C. Anderson
- MRC Centre for Reproductive Health/MRC Human Reproductive Sciences Unit, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, United Kingdom
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh EH4 2XU, Scotland, United Kingdom
| | - Joel W.S. Smith
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh EH4 2XU, Scotland, United Kingdom
| | - Matthew Brook
- MRC Centre for Reproductive Health/MRC Human Reproductive Sciences Unit, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, United Kingdom
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh EH4 2XU, Scotland, United Kingdom
| | - William A. Richardson
- MRC Centre for Reproductive Health/MRC Human Reproductive Sciences Unit, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, United Kingdom
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh EH4 2XU, Scotland, United Kingdom
| | - Nicola K. Gray
- MRC Centre for Reproductive Health/MRC Human Reproductive Sciences Unit, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, United Kingdom
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh EH4 2XU, Scotland, United Kingdom
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Poly(A)-binding proteins are functionally distinct and have essential roles during vertebrate development. Proc Natl Acad Sci U S A 2011; 108:7844-9. [PMID: 21518916 DOI: 10.1073/pnas.1017664108] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Translational control of many mRNAs in developing metazoan embryos is achieved by alterations in their poly(A) tail length. A family of cytoplasmic poly(A)-binding proteins (PABPs) bind the poly(A) tail and can regulate mRNA translation and stability. However, despite the extensive biochemical characterization of one family member (PABP1), surprisingly little is known about their in vivo roles or functional relatedness. Because no information is available in vertebrates, we address their biological roles, establishing that each of the cytoplasmic PABPs conserved in Xenopus laevis [PABP1, embryonic PABP (ePABP), and PABP4] is essential for normal development. Morpholino-mediated knockdown of PABP1 or ePABP causes both anterior and posterior phenotypes and embryonic lethality. In contrast, depletion of PABP4 results mainly in anterior defects and lethality at later stages. Unexpectedly, cross-rescue experiments reveal that neither ePABP nor PABP4 can fully rescue PABP1 depletion, establishing that PABPs have distinct functions. Comparative analysis of the uncharacterized PABP4 with PABP1 and ePABP shows that it shares a mechanistically conserved core role in promoting global translation. Consistent with this analysis, each morphant displays protein synthesis defects, suggesting that their roles in mRNA-specific translational regulation and/or mRNA decay, rather than global translation, underlie the functional differences between PABPs. Domain-swap experiments reveal that the basis of the functional specificity is complex, involving multiple domains of PABPs, and is conferred, at least in part, by protein-protein interactions.
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Abstract
The regulation of translation has emerged as a major determinant of gene expression and is critical for both normal cellular function and the development of disease. Numerous studies have highlighted the diverse, and sometimes related, mechanisms which underlie the regulation of global translation rates and the translational control of specific mRNAs. In the present paper, we discuss the emerging roles of the basal translation factor PABP [poly(A)-binding protein] in mRNA-specific translational control in metazoa which suggest that PABP function is more complex than first recognized.
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MacNicol MC, MacNicol AM. Developmental timing of mRNA translation--integration of distinct regulatory elements. Mol Reprod Dev 2010; 77:662-9. [PMID: 20652998 DOI: 10.1002/mrd.21191] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Targeted mRNA translation is emerging as a critical mechanism to control gene expression during developmental processes. Exciting new findings have revealed a critical role for regulatory elements within the mRNA untranslated regions to direct the timing of mRNA translation. Regulatory elements can be targeted by sequence-specific binding proteins to direct either repression or activation of mRNA translation in response to developmental signals. As new regulatory elements continue to be identified it has become clear that targeted mRNAs can contain multiple regulatory elements, directing apparently contradictory translational patterns. How is this complex regulatory input integrated? In this review, we focus on a new challenge area-how sequence-specific RNA binding proteins respond to developmental signals and functionally integrate to regulate the extent and timing of target mRNA translation. We discuss current understanding with a particular emphasis on the control of cell cycle progression that is mediated through a complex interplay of distinct mRNA regulatory elements during Xenopus oocyte maturation.
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Affiliation(s)
- Melanie C MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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Zhang X, Virtanen A, Kleiman FE. To polyadenylate or to deadenylate: that is the question. Cell Cycle 2010; 9:4437-49. [PMID: 21084869 DOI: 10.4161/cc.9.22.13887] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
mRNA polyadenylation and deadenylation are important processes that allow rapid regulation of gene expression in response to different cellular conditions. Almost all eukaryotic mRNA precursors undergo a co-transcriptional cleavage followed by polyadenylation at the 3' end. After the signals are selected, polyadenylation occurs to full extent, suggesting that this first round of polyadenylation is a default modification for most mRNAs. However, the length of these poly(A) tails changes by the activation of deadenylation, which might regulate gene expression by affecting mRNA stability, mRNA transport, or translation initiation. The mechanisms behind deadenylation activation are highly regulated and associated with cellular conditions such as development, mRNA surveillance, DNA damage response, cell differentiation and cancer. After deadenylation, depending on the cellular response, some mRNAs might undergo an extension of the poly(A) tail or degradation. The polyadenylation/deadenylation machinery itself, miRNAs, or RNA binding factors are involved in the regulation of polyadenylation/deadenylation. Here, we review the mechanistic connections between polyadenylation and deadenylation and how the two processes are regulated in different cellular conditions. It is our conviction that further studies of the interplay between polyadenylation and deadenylation will provide critical information required for a mechanistic understanding of several diseases, including cancer development.
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Affiliation(s)
- Xiaokan Zhang
- Chemistry Department, Hunter College, City University of New York, NY, USA
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Loeber J, Claussen M, Jahn O, Pieler T. Interaction of 42Sp50 with the vegetal RNA localization machinery in Xenopus laevis oocytes. FEBS J 2010; 277:4722-31. [PMID: 20977669 DOI: 10.1111/j.1742-4658.2010.07878.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Localization of a specific subset of maternal mRNAs to the vegetal cortex of Xenopus oocytes is important for the regulation of germ layer formation and germ cell development. It is driven by vegetal localization complexes that are formed with the corresponding signal sequences in the untranslated regions of the mRNAs and with a number of different so-called localization proteins. In the context of the present study, we incorporated tagged variants of the known localization protein Vg1RBP into vegetal localization complexes by means of oocyte microinjection. Immunoprecipitation of the corresponding RNPs allowed for the identification of novel Vg1RBP-associated proteins, such as the embryonic poly(A) binding protein, the Y-box RNA-packaging protein 2B and the oocyte-specific version of the elongation factor 1α (42Sp50). Incorporation of 42Sp50 into localization RNPs could be confirmed by co-immunoprecipitation of Vg1RBP and Staufen1 with myc-tagged 42Sp50. Furthermore, myc-42Sp50 was found to co-sediment with the same two proteins in large, RNAse-sensitive complexes, as well as to associate specifically with several vegetally localizing mRNAs but not with nonlocalized control RNAs. Finally, oocyte microinjection experiments reveal that 42Sp50 is a protein that shuttles between the nucleus and cytoplasm. Taken together, these observations provide evidence for a novel function of 42Sp50 in the context of vegetal mRNA transport in Xenopus oocytes.
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Affiliation(s)
- Jana Loeber
- Department of Developmental Biochemistry, Göttingen Center for Molecular Biosciences, University of Göttingen, Göttingen, Germany
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Nakamura Y, Tanaka KJ, Miyauchi M, Huang L, Tsujimoto M, Matsumoto K. Translational repression by the oocyte-specific protein P100 in Xenopus. Dev Biol 2010; 344:272-83. [PMID: 20471969 DOI: 10.1016/j.ydbio.2010.05.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 04/09/2010] [Accepted: 05/07/2010] [Indexed: 01/10/2023]
Abstract
The translational regulation of maternal mRNAs is one of the most important steps in the control of temporal-spatial gene expression during oocyte maturation and early embryogenesis in various species. Recently, it has become clear that protein components of mRNPs play essential roles in the translational regulation of maternal mRNAs. In the present study, we investigated the function of P100 in Xenopus oocytes. P100 exhibits sequence conservation with budding yeast Pat1 and is likely the orthologue of human Pat1a (also called PatL2). P100 is maternally expressed in immature oocytes, but disappears during oocyte maturation. In oocytes, P100 is an RNA binding component of ribosome-free mRNPs, associating with other mRNP components such as Xp54, xRAP55 and CPEB. Translational repression by overexpression of P100 occurred when reporter mRNAs were injected into oocytes. Intriguingly, we found that when P100 was overexpressed in the oocytes, the kinetics of oocyte maturation was considerably retarded. In addition, overexpression of P100 in oocytes significantly affected the accumulation of c-Mos and cyclin B1 during oocyte maturation. These results suggest that P100 plays a role in regulating the translation of specific maternal mRNAs required for the progression of Xenopus oocyte maturation.
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Affiliation(s)
- Yoriko Nakamura
- Laboratory of Cellular Biochemistry, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Minshall N, Allison R, Marnef A, Wilczynska A, Standart N. Translational control assessed using the tethered function assay in Xenopus oocytes. Methods 2010; 51:165-9. [PMID: 20188836 DOI: 10.1016/j.ymeth.2010.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 02/18/2010] [Accepted: 02/20/2010] [Indexed: 10/19/2022] Open
Abstract
The tethered function assay is a method designed to address the role of an RNA-binding protein upon the metabolism of a reporter RNA. The basis of this assay is to artificially tether a test protein to a reporter mRNA by employing an unrelated bacteriophage MS2 or lambda N RNA-protein interaction, and to assess the effects of the test protein on the reporter RNA. In this chapter, we first discuss the principles and validity of the tethered function approach, drawing on appropriate examples from several cell types and of many proteins that regulate RNA in a variety of processes, including RNA processing (splicing, polyadenylation/deadenylation, decay), localisation and protein synthesis. Secondly, we will focus on the use of this approach to monitor translational activation and repression in Xenopus oocytes, giving a detailed protocol, and discussing possible optimizations we have explored.
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Affiliation(s)
- Nicola Minshall
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, UK
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Biase FH, Martelli L, Puga R, Giuliatti S, Santos-Biase WKF, Fonseca Merighe GK, Meirelles FV. Messenger RNA expression of Pabpnl1 and Mbd3l2 genes in oocytes and cleavage embryos. Fertil Steril 2009; 93:2507-12. [PMID: 19819433 DOI: 10.1016/j.fertnstert.2009.08.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 08/18/2009] [Accepted: 08/19/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To identify genes specifically expressed in mammalian oocytes using an in silico subtraction, and to characterize the mRNA patterns of selected genes in oocytes, embryos, and adult tissues. DESIGN Comparison between oocyte groups and between early embryo stages. SETTING Laboratories of embryo manipulation and molecular biology from Departamento de Genética (FMRP) and Departamento de Ciências Básicas (FZEA)--University of São Paulo. SAMPLE(S) Oocytes were collected from slaughtered cows for measurements, in vitro fertilization, and in vitro embryo culture. Somatic tissue, excluding gonad and uterus tissue, was collected from male and female cattle. MAIN OUTCOME MEASURE(S) Messenger RNA levels of poly(A)-binding protein nuclear-like 1 (Pabpnl1) and methyl-CpG-binding domain protein 3-like 2 (Mbd3l2). RESULT(S) Pabpnl1 mRNA was found to be expressed in oocytes, and Mbd3l2 transcripts were present in embryos. Quantification of Pabpnl1 transcripts showed no difference in levels between good- and bad-quality oocytes before in vitro maturation (IVM) or between good-quality oocytes before and after IVM. However, Pabpnl1 transcripts were not detected in bad-quality oocytes after IVM. Transcripts of the Mbd3l2 gene were found in 4-cell, 8-cell, and morula-stage embryos, with the highest level observed in 8-cell embryos. CONCLUSION(S) Pabpnl1 gene expression is restricted to oocytes and Mbd3l2 to embryos. Different Pabpnl1 mRNA levels in oocytes of varying viability suggest an important role in fertility involving the oocyte potential for embryo development.
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McGivern JV, Swaney DL, Coon JJ, Sheets MD. Toward defining the phosphoproteome of Xenopus laevis embryos. Dev Dyn 2009; 238:1433-43. [PMID: 19384857 DOI: 10.1002/dvdy.21941] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Phosphorylation is universally used for controlling protein function, but knowledge of the phosphoproteome in vertebrate embryos has been limited. However, recent technical advances make it possible to define an organism's phosphoproteome at a more comprehensive level. Xenopus laevis offers established advantages for analyzing the regulation of protein function by phosphorylation. Functionally unbiased, comprehensive information about the Xenopus phosphoproteome would provide a powerful guide for future studies of phosphorylation in a developmental context. To this end, we performed a phosphoproteomic analysis of Xenopus oocytes, eggs, and embryos using recently developed mass spectrometry methods. We identified 1,441 phosphorylation sites present on 654 different Xenopus proteins, including hundreds of previously unknown phosphorylation sites. This approach identified several phosphorylation sites described in the literature and/or evolutionarily conserved in other organisms, validating the data's quality. These data will serve as a powerful resource for the exploration of phosphorylation and protein function within a developmental context. Developmental Dynamics 238:1433-1443, 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Jered V McGivern
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Madison, Wisconsin, USA
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Brook M, Smith JWS, Gray NK. The DAZL and PABP families: RNA-binding proteins with interrelated roles in translational control in oocytes. Reproduction 2009; 137:595-617. [DOI: 10.1530/rep-08-0524] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gametogenesis is a highly complex process that requires the exquisite temporal, spatial and amplitudinal regulation of gene expression at multiple levels. Translational regulation is important in a wide variety of cell types but may be even more prevalent in germ cells, where periods of transcriptional quiescence necessitate the use of post-transcriptional mechanisms to effect changes in gene expression. Consistent with this, studies in multiple animal models have revealed an essential role for mRNA translation in the establishment and maintenance of reproductive competence. While studies in humans are less advanced, emerging evidence suggests that translational regulation plays a similarly important role in human germ cells and fertility. This review highlights specific mechanisms of translational regulation that play critical roles in oogenesis by activating subsets of mRNAs. These mRNAs are activated in a strictly determined temporal manner via elements located within their 3′UTR, which serve as binding sites fortrans-acting factors. While we concentrate on oogenesis, these regulatory events also play important roles during spermatogenesis. In particular, we focus on the deleted in azoospermia-like (DAZL) family of proteins, recently implicated in the translational control of specific mRNAs in germ cells; their relationship with the general translation initiation factor poly(A)-binding protein (PABP) and the process of cytoplasmic mRNA polyadenylation.
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Minshall N, Kress M, Weil D, Standart N. Role of p54 RNA helicase activity and its C-terminal domain in translational repression, P-body localization and assembly. Mol Biol Cell 2009; 20:2464-72. [PMID: 19297524 DOI: 10.1091/mbc.e09-01-0035] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The RNA helicase p54 (DDX6, Dhh1, Me31B, Cgh-1, RCK) is a prototypic component of P-(rocessing) bodies in cells ranging from yeast to human. Previously, we have shown that it is also a component of the large cytoplasmic polyadenylation element-binding protein translation repressor complex in Xenopus oocytes and that when tethered to the 3' untranslated region, Xp54 represses reporter mRNA translation. Here, we examine the role of the p54 helicase activity in translational repression and in P-body formation. Mutagenesis of conserved p54 helicase motifs activates translation in the tethered function assay, reduces accumulation of p54 in P-bodies in HeLa cells, and inhibits its capacity to assemble P-bodies in p54-depleted cells. Similar results were obtained in four helicase motifs implicated in ATP binding and in coupling ATPase and RNA binding activities. This is accompanied by changes in the interaction of the mutant p54 with the oocyte repressor complex components. Surprisingly, the C-terminal D2 domain alone is sufficient for translational repression and complete accumulation in P-bodies, although it is deficient for P-body assembly. We propose a novel RNA helicase model, in which the D2 domain acts as a protein binding platform and the ATPase/helicase activity allows protein complex remodeling that dictates the balance between repressors and an activator of translation.
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Affiliation(s)
- Nicola Minshall
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
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43
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The herpes simplex virus type 1 multiple function protein ICP27. Virol Sin 2008. [DOI: 10.1007/s12250-008-2993-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Kimura M, Ishida K, Kashiwabara SI, Baba T. Characterization of two cytoplasmic poly(A)-binding proteins, PABPC1 and PABPC2, in mouse spermatogenic cells. Biol Reprod 2008; 80:545-54. [PMID: 19020299 DOI: 10.1095/biolreprod.108.072553] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Mouse spermatogenic cells are known to contain at least two isoforms of cytoplasmic poly(A)-binding proteins, PABPC1 and PABPC2 (previously known as PABPT). In this study, we have characterized PABPC1 and PABPC2. PABPC2 was present in pachytene spermatocytes and round spermatids, whereas elongating spermatids still included PABPC1. These two proteins are capable of binding mRNA poly(A) tails nonspecifically and of directly associating with each other and with several translational regulators, including EIF4G1, PAIP1, PAIP2, and PIWIL1 (previously known as MIWI). Moreover, both PABPC1 and PABPC2 exhibited the ability to enhance translation of a reporter mRNA in vitro. Despite these similarities, PABPC2 was distinguished from PABPC1 by the absence of PABPC2 in actively translating polyribosomes of testicular cells. PABPC1 was distributed in polyribosomes and in translationally inactive messenger ribonucleoprotein particles. Most importantly, PABPC2 and PIWIL1 were noticeably enriched in the chromatoid body of round spermatids. These results suggest that PABPC2 may function in translational repression during spermatogenesis.
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Affiliation(s)
- Masanori Kimura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba Science City, Ibaraki, Japan
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Guzeloglu-Kayisli O, Pauli S, Demir H, Lalioti MD, Sakkas D, Seli E. Identification and characterization of human embryonic poly(A) binding protein (EPAB). Mol Hum Reprod 2008; 14:581-8. [PMID: 18716053 DOI: 10.1093/molehr/gan047] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Transcriptional silencing that begins with oocyte maturation persists during the initial mitotic divisions of the embryo. Gene expression during this period largely depends on the translational activation of maternal mRNAs by cytoplasmic polyadenylation and requires an embryonic poly(A) binding protein (EPAB). EPAB has been identified in Xenopus and mouse, where it is expressed exclusively in oocytes and early embryos until zygotic genome activation (ZGA) when it is replaced by the somatic cytoplasmic poly(A) binding protein (PABPC1). EPAB plays a central role in the regulation of maternal mRNA activation by preventing deadenylation and promoting translation. In this study, we identified and characterized the human EPAB ortholog. Human EPAB is a 619 amino acid protein with 77% identity and 84% similarity to mouse EPAB. Human EPAB mRNA is detected in ovaries, testes and several somatic tissues including pancreas, liver and thymus. Similar to the observations in Xenopus and mouse, human EPAB is the predominant poly(A) binding protein in immature (germinal vesicle) and mature (metaphase II) oocytes, and it is replaced by PABPC1 following ZGA, which occurs at 4- to 8-cell stage in human. Our findings suggest that the unique translational regulatory pathways that control gene expression during oogenesis and early embryo development may be common between model organisms and humans.
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Affiliation(s)
- Ozlem Guzeloglu-Kayisli
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT 06520, USA
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Martinez-Godoy MA, Mauri N, Juarez J, Marques MC, Santiago J, Forment J, Gadea J. A genome-wide 20 K citrus microarray for gene expression analysis. BMC Genomics 2008; 9:318. [PMID: 18598343 PMCID: PMC2483987 DOI: 10.1186/1471-2164-9-318] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 07/03/2008] [Indexed: 11/24/2022] Open
Abstract
Background Understanding of genetic elements that contribute to key aspects of citrus biology will impact future improvements in this economically important crop. Global gene expression analysis demands microarray platforms with a high genome coverage. In the last years, genome-wide EST collections have been generated in citrus, opening the possibility to create new tools for functional genomics in this crop plant. Results We have designed and constructed a publicly available genome-wide cDNA microarray that include 21,081 putative unigenes of citrus. As a functional companion to the microarray, a web-browsable database [1] was created and populated with information about the unigenes represented in the microarray, including cDNA libraries, isolated clones, raw and processed nucleotide and protein sequences, and results of all the structural and functional annotation of the unigenes, like general description, BLAST hits, putative Arabidopsis orthologs, microsatellites, putative SNPs, GO classification and PFAM domains. We have performed a Gene Ontology comparison with the full set of Arabidopsis proteins to estimate the genome coverage of the microarray. We have also performed microarray hybridizations to check its usability. Conclusion This new cDNA microarray replaces the first 7K microarray generated two years ago and allows gene expression analysis at a more global scale. We have followed a rational design to minimize cross-hybridization while maintaining its utility for different citrus species. Furthermore, we also provide access to a website with full structural and functional annotation of the unigenes represented in the microarray, along with the ability to use this site to directly perform gene expression analysis using standard tools at different publicly available servers. Furthermore, we show how this microarray offers a good representation of the citrus genome and present the usefulness of this genomic tool for global studies in citrus by using it to catalogue genes expressed in citrus globular embryos.
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Affiliation(s)
- M Angeles Martinez-Godoy
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Laboratorio de Genomica (Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas), Avenida de los Naranjos s/n, E46022 Valencia, Spain.
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Translational control by cytoplasmic polyadenylation in Xenopus oocytes. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2008; 1779:217-29. [PMID: 18316045 PMCID: PMC2323027 DOI: 10.1016/j.bbagrm.2008.02.002] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 01/30/2008] [Accepted: 02/04/2008] [Indexed: 12/21/2022]
Abstract
Elongation of the poly(A) tails of specific mRNAs in the cytoplasm is a crucial regulatory step in oogenesis and early development of many animal species. The best studied example is the regulation of translation by cytoplasmic polyadenylation elements (CPEs) in the 3′ untranslated region of mRNAs involved in Xenopus oocyte maturation. In this review we discuss the mechanism of translational control by the CPE binding protein (CPEB) in Xenopus oocytes as follows:The cytoplasmic polyadenylation machinery such as CPEB, the subunits of cleavage and polyadenylation specificity factor (CPSF), symplekin, Gld-2 and poly(A) polymerase (PAP). The signal transduction that leads to the activation of CPE-mediated polyadenylation during oocyte maturation, including the potential roles of kinases such as MAPK, Aurora A, CamKII, cdk1/Ringo and cdk1/cyclin B. The role of deadenylation and translational repression, including the potential involvement of PARN, CCR4/NOT, maskin, pumilio, Xp54 (Ddx6, Rck), other P-body components and isoforms of the cap binding initiation factor eIF4E.
Finally we discuss some of the remaining questions regarding the mechanisms of translational regulation by cytoplasmic polyadenylation and give our view on where our knowledge is likely to be expanded in the near future.
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Voltmer-Irsch S, Kneissel S, Adenot PG, Schmidt-Zachmann MS. Regulatory mechanisms governing the oocyte-specific synthesis of the karyoskeletal protein NO145. J Cell Sci 2007; 120:1412-22. [PMID: 17374641 DOI: 10.1242/jcs.000166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Given the prominence and the biological importance of the nucleus it is remarkable how little is still known about structure-forming proteins in the nuclear interior. The karyoskeletal protein NO145 has been identified as a major constituent of a filamentous network surrounding the amplified nucleoli of Xenopus laevis oocytes. We now show that an orthologous protein also occurs in female germ cells of a wide range of other vertebrates, where it forms dot-like structures. Using the Xenopus oocyte system we further report a specific regulatory mechanism responsible for (1) the rapid degradation of the NO145 protein during meiotic maturation, and (2) the cell-type-dependent translation of NO145 mRNA. Microinjection experiments have revealed that NO145 is a target of proteasomes and the use of the rapid amplification of cDNA ends-polyadenylation test (RACE-PAT) has disclosed the existence of NO145 mRNAs differing in their 3' UTRs. Reporter systems as well as polyribosome profiling experiments have revealed the regulatory importance of the 3' UTRs, which affect the translational efficiency as well as the stability of the encoded protein. The highly conserved cell-type specificity and the extremely tight temporal regulation of NO145 synthesis suggest an important role of this protein in female meiotic prophase.
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Larralde O, Smith RWP, Wilkie GS, Malik P, Gray NK, Clements JB. Direct stimulation of translation by the multifunctional herpesvirus ICP27 protein. J Virol 2006; 80:1588-91. [PMID: 16415034 PMCID: PMC1346932 DOI: 10.1128/jvi.80.3.1588-1591.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) ICP27 protein is an essential regulator of viral gene expression with roles at various levels of RNA metabolism in the nucleus. Using the tethered function assay, we showed a cytoplasmic activity for ICP27 in directly enhancing mRNA translation in vivo in the absence of other viral factors. The region of ICP27 required for translational stimulation maps to the C terminus. Furthermore, in infected cells, ICP27 is associated with polyribosomes, indicating a function in translation during the lytic cycle.
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Affiliation(s)
- Osmany Larralde
- MRC Human Genetics Unit, Western General Hospital, Edinburgh EH4 2XU, Scotland, United Kingdom
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Vasudevan S, Seli E, Steitz JA. Metazoan oocyte and early embryo development program: a progression through translation regulatory cascades. Genes Dev 2006; 20:138-46. [PMID: 16418480 DOI: 10.1101/gad.1398906] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Shobha Vasudevan
- Department of Molecular Biophysics and Biochemistry, and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06536, USA
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