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Eldem V, Zararsız G, Erkan M. Global expression pattern of genes containing positively selected sites in European anchovy (Engraulis encrasicolus L.) may shed light on teleost reproduction. PLoS One 2023; 18:e0289940. [PMID: 37566603 PMCID: PMC10420382 DOI: 10.1371/journal.pone.0289940] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 07/30/2023] [Indexed: 08/13/2023] Open
Abstract
European anchovy is a multiple-spawning and highly fecundate pelagic fish with high economic and ecological significance. Although fecundity is influenced by nutrition, temperature and weight of spawners, high reproductive capacity is related to molecular processes in the ovary. The ovary is an essential and complex reproductive organ composed of various somatic and germ cells, which interact to facilitate the development of the ovary and functional oocytes. Revealing the ovarian transcriptome profile of highly fecundate fishes provides insights into oocyte production in teleosts. Here we use a comprehensive tissue-specific RNA sequencing which yielded 102.3 billion clean bases to analyze the transcriptional profiles of the ovary compared with other organs (liver, kidney, ovary, testis, fin, cauda and gill) and juvenile tissues of European anchovy. We conducted a comparative transcriptome and positive selection analysis of seven teleost species with varying fecundity rates to identify genes potentially involved in oogenesis and oocyte development. Of the 2,272 single copies of orthologous genes found, up to 535 genes were under positive selection in European anchovy and these genes are associated with a wide spectrum of cellular and molecular functions, with enrichments such as RNA methylation and modification, ribosome biogenesis, DNA repair, cell cycle processing and peptide/amide biosynthesis. Of the 535 positively selected genes, 55 were upregulated, and 45 were downregulated in the ovary, most of which were related to RNA and DNA transferase, developmental transcription factors, protein kinases and replication factors. Overall, our analysis of the transcriptome level in the ovarian tissue of a teleost will provide further insights into molecular processes and deepen our genetic understanding of egg production in highly fecund fish.
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Affiliation(s)
- Vahap Eldem
- Faculty of Sciences, Department of Biology, Istanbul University, Istanbul, Turkey
| | - Gökmen Zararsız
- Department of Biostatistics, Erciyes University, Kayseri, Turkey
| | - Melike Erkan
- Faculty of Sciences, Department of Biology, Istanbul University, Istanbul, Turkey
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2
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Martino NA, Picardi E, Ciani E, D’Erchia AM, Bogliolo L, Ariu F, Mastrorocco A, Temerario L, Mansi L, Palumbo V, Pesole G, Dell’Aquila ME. Cumulus Cell Transcriptome after Cumulus-Oocyte Complex Exposure to Nanomolar Cadmium in an In Vitro Animal Model of Prepubertal and Adult Age. BIOLOGY 2023; 12:biology12020249. [PMID: 36829526 PMCID: PMC9953098 DOI: 10.3390/biology12020249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/25/2023] [Accepted: 02/02/2023] [Indexed: 02/09/2023]
Abstract
Cadmium (Cd), a highly toxic pollutant, impairs oocyte fertilization, through oxidative damage on cumulus cells (CCs). This study analysed the transcriptomic profile of CCs of cumulus-oocyte complexes (COCs) from adult and prepubertal sheep, exposed to Cd nanomolar concentration during in vitro maturation. In both age-groups, CCs of matured oocytes underwent RNA-seq, data analysis and validation. Differentially expressed genes (DEGs) were identified in adult (n = 99 DEGs) and prepubertal (n = 18 DEGs) CCs upon Cd exposure. Transcriptomes of adult CCs clustered separately between Cd-exposed and control samples, whereas prepubertal ones did not as observed by Principal Component Analysis. The transcriptomic signature of Cd-induced CC toxicity was identified by gene annotation and literature search. Genes associated with previous studies on ovarian functions and/or Cd effects were confirmed and new genes were identified, thus implementing the knowledge on their involvement in such processes. Enrichment and validation analysis showed that, in adult CCs, Cd acted as endocrine disruptor on DEGs involved in hormone biosynthesis, cumulus expansion, regulation of cell signalling, growth and differentiation and oocyte maturation, whereas in prepubertal CCs, Cd affected DEGs involved in CC development and viability and CC-oocyte communications. In conclusion, these DEGs could be used as valuable non-invasive biomarkers for oocyte competence.
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Affiliation(s)
- Nicola Antonio Martino
- Department of Biosciences, Biotechnologies & Environment, University of Bari Aldo Moro, Via Edoardo Orabona, 70125 Bari, Italy
- Correspondence: ; Tel.: +39-0805443888
| | - Ernesto Picardi
- Department of Biosciences, Biotechnologies & Environment, University of Bari Aldo Moro, Via Edoardo Orabona, 70125 Bari, Italy
| | - Elena Ciani
- Department of Biosciences, Biotechnologies & Environment, University of Bari Aldo Moro, Via Edoardo Orabona, 70125 Bari, Italy
| | - Anna Maria D’Erchia
- Department of Biosciences, Biotechnologies & Environment, University of Bari Aldo Moro, Via Edoardo Orabona, 70125 Bari, Italy
| | - Luisa Bogliolo
- Department of Veterinary Medicine, University of Sassari, Via Vienna n. 2, 07100 Sassari, Italy
| | - Federica Ariu
- Department of Veterinary Medicine, University of Sassari, Via Vienna n. 2, 07100 Sassari, Italy
| | - Antonella Mastrorocco
- Department of Biosciences, Biotechnologies & Environment, University of Bari Aldo Moro, Via Edoardo Orabona, 70125 Bari, Italy
| | - Letizia Temerario
- Department of Biosciences, Biotechnologies & Environment, University of Bari Aldo Moro, Via Edoardo Orabona, 70125 Bari, Italy
| | - Luigi Mansi
- Department of Biosciences, Biotechnologies & Environment, University of Bari Aldo Moro, Via Edoardo Orabona, 70125 Bari, Italy
| | - Valeria Palumbo
- Department of Biosciences, Biotechnologies & Environment, University of Bari Aldo Moro, Via Edoardo Orabona, 70125 Bari, Italy
| | - Graziano Pesole
- Department of Biosciences, Biotechnologies & Environment, University of Bari Aldo Moro, Via Edoardo Orabona, 70125 Bari, Italy
| | - Maria Elena Dell’Aquila
- Department of Biosciences, Biotechnologies & Environment, University of Bari Aldo Moro, Via Edoardo Orabona, 70125 Bari, Italy
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Jia B, Xiang D, Shao Q, Hong Q, Quan G, Wu G. Proteomic Exploration of Porcine Oocytes During Meiotic Maturation in vitro Using an Accurate TMT-Based Quantitative Approach. Front Vet Sci 2022; 8:792869. [PMID: 35198619 PMCID: PMC8859466 DOI: 10.3389/fvets.2021.792869] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 12/20/2021] [Indexed: 01/19/2023] Open
Abstract
The dynamic changes in protein expression are well known to be required for oocyte meiotic maturation. Although proteomic analysis has been performed in porcine oocytes during in vitro maturation, there is still no full data because of the technical limitations at that time. Here, a novel tandem mass tag (TMT)-based quantitative approach was used to compare the proteomic profiles of porcine immature and in vitro mature oocytes. The results of our study showed that there were 763 proteins considered with significant difference−450 over-expressed and 313 under-expressed proteins. The GO and KEGG analyses revealed multiple regulatory mechanisms of oocyte nuclear and cytoplasmic maturation such as spindle and chromosome configurations, cytoskeletal reconstruction, epigenetic modifications, energy metabolism, signal transduction and others. In addition, 12 proteins identified with high-confidence peptide and related to oocyte maturation were quantified by a parallel reaction monitoring technique to validate the reliability of TMT results. In conclusion, we provided a detailed proteomics dataset to enrich the understanding of molecular characteristics underlying porcine oocyte maturation in vitro.
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Affiliation(s)
- Baoyu Jia
- Key Laboratory of Animal Gene Editing and Animal Cloning in Yunnan Province, College of Veterinary Medicine, Yunnan Agricultural University, Kunming, China
| | - Decai Xiang
- Yunnan Provincial Genebank of Livestock and Poultry Genetic Resources, Yunnan Provincial Engineering Laboratory of Animal Genetic Resource Conservation and Germplasm Enhancement, Yunnan Animal Science and Veterinary Institute, Kunming, China
| | - Qingyong Shao
- Yunnan Provincial Genebank of Livestock and Poultry Genetic Resources, Yunnan Provincial Engineering Laboratory of Animal Genetic Resource Conservation and Germplasm Enhancement, Yunnan Animal Science and Veterinary Institute, Kunming, China
| | - Qionghua Hong
- Yunnan Provincial Genebank of Livestock and Poultry Genetic Resources, Yunnan Provincial Engineering Laboratory of Animal Genetic Resource Conservation and Germplasm Enhancement, Yunnan Animal Science and Veterinary Institute, Kunming, China
| | - Guobo Quan
- Yunnan Provincial Genebank of Livestock and Poultry Genetic Resources, Yunnan Provincial Engineering Laboratory of Animal Genetic Resource Conservation and Germplasm Enhancement, Yunnan Animal Science and Veterinary Institute, Kunming, China
- *Correspondence: Guobo Quan
| | - Guoquan Wu
- Yunnan Provincial Genebank of Livestock and Poultry Genetic Resources, Yunnan Provincial Engineering Laboratory of Animal Genetic Resource Conservation and Germplasm Enhancement, Yunnan Animal Science and Veterinary Institute, Kunming, China
- Guoquan Wu
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4
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Yi ZY, Meng TG, Ma XS, Li J, Zhang CH, Ouyang YC, Schatten H, Qiao J, Sun QY, Qian WP. CDC6 regulates both G2/M transition and metaphase-to-anaphase transition during the first meiosis of mouse oocytes. J Cell Physiol 2020; 235:5541-5554. [PMID: 31984513 DOI: 10.1002/jcp.29469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 01/06/2020] [Indexed: 12/30/2022]
Abstract
Cell division cycle protein, CDC6, is essential for the initiation of DNA replication. CDC6 was recently shown to inhibit the microtubule-organizing activity of the centrosome. Here, we show that CDC6 is localized to the spindle from pro-metaphase I (MI) to MII stages of oocytes, and it plays important roles at two critical steps of oocyte meiotic maturation. CDC6 depletion facilitated the G2/M transition (germinal vesicle breakdown [GVBD]) through regulation of Cdh1 and cyclin B1 expression and CDK1 (CDC2) phosphorylation in a GVBD-inhibiting culture system containing milrinone. Furthermore, GVBD was significantly decreased after knockdown of cyclin B1 in CDC6-depleted oocytes, indicating that the effect of CDC6 loss on GVBD stimulation was mediated, at least in part, by raising cyclin B1. Knockdown of CDC6 also caused abnormal localization of γ-tubulin, resulting in defective spindles, misaligned chromosomes, cyclin B1 accumulation, and spindle assembly checkpoint (SAC) activation, leading to significant pro-MI/MI arrest and PB1 extrusion failure. These phenotypes were also confirmed by time-lapse live cell imaging analysis. The results indicate that CDC6 is indispensable for maintaining G2 arrest of meiosis and functions in G2/M checkpoint regulation in mouse oocytes. Moreover, CDC6 is also a key player regulating meiotic spindle assembly and metaphase-to-anaphase transition in meiotic oocytes.
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Affiliation(s)
- Zi-Yun Yi
- The Reproductive Medicine Center, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Tie-Gang Meng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xue-Shan Ma
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Jian Li
- The Reproductive Medicine Center, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Chun-Hui Zhang
- The Reproductive Medicine Center, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Ying-Chun Ouyang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri
| | - Jie Qiao
- Reproductive Medical Center, Peking University Third Hospital, Beijing, China
| | - Qing-Yuan Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Wei-Ping Qian
- The Reproductive Medicine Center, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
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Dębowski M, Szymańska Z, Kubiak JZ, Lachowicz M. Mathematical Model Explaining the Role of CDC6 in the Diauxic Growth of CDK1 Activity during the M-Phase of the Cell Cycle. Cells 2019; 8:cells8121537. [PMID: 31795221 PMCID: PMC6952973 DOI: 10.3390/cells8121537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 11/22/2019] [Accepted: 11/25/2019] [Indexed: 11/17/2022] Open
Abstract
In this paper we propose a role for the CDC6 protein in the entry of cells into mitosis. This has not been considered in the literature so far. Recent experiments suggest that CDC6, upon entry into mitosis, inhibits the appearance of active CDK1 and cyclin B complexes. This paper proposes a mathematical model which incorporates the dynamics of kinase CDK1, its regulatory protein cyclin B, the regulatory phosphatase CDC25 and the inhibitor CDC6 known to be involved in the regulation of active CDK1 and cyclin B complexes. The experimental data lead us to formulate a new hypothesis that CDC6 slows down the activation of inactive complexes of CDK1 and cyclin B upon mitotic entry. Our mathematical model, based on mass action kinetics, provides a possible explanation for the experimental data. We claim that the dynamics of active complexes CDK1 and cyclin B have a similar nature to diauxic dynamics introduced by Monod in 1949. In mathematical terms we state it as the existence of more than one inflection point of the curve defining the dynamics of the complexes.
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Affiliation(s)
- Mateusz Dębowski
- Faculty of Mathematics, Informatics and Mechanics, Institute of Applied Mathematics and Mechanics, University of Warsaw, ul. Banacha 2, 02-097 Warsaw, Poland
| | - Zuzanna Szymańska
- Institute of Mathematics, Polish Academy of Sciences, ul. Śniadeckich 8, 00-656 Warsaw, Poland or
- ICM, University of Warsaw, ul. Tyniecka 15/17, 02-630 Warsaw, Poland
| | - Jacek Z. Kubiak
- CNRS, Institute of Genetics and Development of Rennes, Univ Rennes, UMR 6290, Cell Cycle Group, Faculty of Medicine, F-35000 Rennes, France
- Laboratory of Regenerative Medicine and Cell Biology, Military Institute of Hygiene and Epidemiology (WIHE), ul. Kozielska 4, 01-163 Warsaw, Poland
- Correspondence: (J.Z.K.); (M.L.)
| | - Mirosław Lachowicz
- Faculty of Mathematics, Informatics and Mechanics, Institute of Applied Mathematics and Mechanics, University of Warsaw, ul. Banacha 2, 02-097 Warsaw, Poland
- Correspondence: (J.Z.K.); (M.L.)
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Schultz RM, Stein P, Svoboda P. The oocyte-to-embryo transition in mouse: past, present, and future. Biol Reprod 2019; 99:160-174. [PMID: 29462259 DOI: 10.1093/biolre/ioy013] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/03/2018] [Indexed: 02/06/2023] Open
Abstract
The oocyte-to-embryo transition (OET) arguably initiates with formation of a primordial follicle and culminates with reprogramming of gene expression during the course of zygotic genome activation. This transition results in converting a highly differentiated cell, i.e. oocyte, to undifferentiated cells, i.e. initial blastomeres of a preimplantation embryo. A plethora of changes occur during the OET and include, but are not limited to, changes in transcription, chromatin structure, and protein synthesis; accumulation of macromolecules and organelles that will comprise the oocyte's maternal contribution to the early embryo; sequential acquisition of meiotic and developmental competence to name but a few. This review will focus on transcriptional and post-transcriptional changes that occur during OET in mouse because such changes are likely the major driving force for OET. We often take a historical and personal perspective, and highlight how advances in experimental methods often catalyzed conceptual advances in understanding the molecular bases for OET. We also point out questions that remain open and therefore represent topics of interest for future investigation.
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Affiliation(s)
- Richard M Schultz
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Anatomy, Physiology, Cell Biology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Paula Stein
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, USA
| | - Petr Svoboda
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Yao L, Chen J, Wu X, Jia S, Meng A. Zebrafish cdc6 hypomorphic mutation causes Meier-Gorlin syndrome-like phenotype. Hum Mol Genet 2018; 26:4168-4180. [PMID: 28985365 PMCID: PMC5886151 DOI: 10.1093/hmg/ddx305] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/26/2017] [Indexed: 11/13/2022] Open
Abstract
Cell Division Cycle 6 (Cdc6) is a component of pre-replicative complex (preRC) forming on DNA replication origins in eukaryotes. Recessive mutations in ORC1, ORC4, ORC6, CDT1 or CDC6 of the preRC in human cause Meier-Gorlin syndrome (MGS) that is characterized by impaired post-natal growth, short stature and microcephaly. However, vertebrate models of MGS have not been reported. Through N-ethyl-N-nitrosourea mutagenesis and Cas9 knockout, we generate several cdc6 mutant lines in zebrafish. Loss-of-function mutations of cdc6, as manifested by cdc6tsu4305 and cdc6tsu7cd mutants, lead to embryonic lethality due to cell cycle arrest at the S phase and extensive apoptosis. Embryos homozygous for a cdc6 hypomorphic mutation, cdc6tsu21cd, develop normally during embryogenesis. Later on, compared with their wild-type (WT) siblings, cdc6tsu21cd mutant fish show growth retardation, and their body weight and length in adulthood are greatly reduced, which resemble human MGS. Surprisingly, cdc6tsu21cd mutant fish become males with a short life and fail to mate with WT females, suggesting defective reproduction. Overexpression of Cdc6 mutant forms, which mimic human CDC6(T323R) mutation found in a MGS patient, in zebrafish cdc6tsu4305 mutant embryos partially represses cell death phenotype, suggesting that the human CDC6(T323R) mutation is a hypomorph. cdc6tsu21cd mutant fish will be useful to detect more tissue defects and develop medical treatment strategies for MGS patients.
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Affiliation(s)
- Likun Yao
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jing Chen
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaotong Wu
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shunji Jia
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Anming Meng
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
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Microtubule-actin crosslinking factor 1 (Macf1) domain function in Balbiani body dissociation and nuclear positioning. PLoS Genet 2017; 13:e1006983. [PMID: 28880872 PMCID: PMC5605089 DOI: 10.1371/journal.pgen.1006983] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 09/19/2017] [Accepted: 08/17/2017] [Indexed: 12/31/2022] Open
Abstract
Animal-vegetal (AV) polarity of most vertebrate eggs is established during early oogenesis through the formation and disassembly of the Balbiani Body (Bb). The Bb is a structure conserved from insects to humans that appears as a large granule, similar to a mRNP granule composed of mRNA and proteins, that in addition contains mitochondria, ER and Golgi. The components of the Bb, which have amyloid-like properties, include germ cell and axis determinants of the embryo that are anchored to the vegetal cortex upon Bb disassembly. Our lab discovered in zebrafish the only gene known to function in Bb disassembly, microtubule-actin crosslinking factor 1a (macf1a). Macf1 is a conserved, giant multi-domain cytoskeletal linker protein that can interact with microtubules (MTs), actin filaments (AF), and intermediate filaments (IF). In macf1a mutant oocytes the Bb fails to dissociate, the nucleus is acentric, and AV polarity of the oocyte and egg fails to form. The cytoskeleton-dependent mechanism by which Macf1a regulates Bb mRNP granule dissociation was unknown. We found that disruption of AFs phenocopies the macf1a mutant phenotype, while MT disruption does not. We determined that cytokeratins (CK), a type of IF, are enriched in the Bb. We found that Macf1a localizes to the Bb, indicating a direct function in regulating its dissociation. We thus tested if Macf1a functions via its actin binding domain (ABD) and plectin repeat domain (PRD) to integrate cortical actin and Bb CK, respectively, to mediate Bb dissociation at the oocyte cortex. We developed a CRISPR/Cas9 approach to delete the exons encoding these domains from the macf1a endogenous locus, while maintaining the open reading frame. Our analysis shows that Macf1a functions via its ABD to mediate Bb granule dissociation and nuclear positioning, while the PRD is dispensable. We propose that Macf1a does not function via its canonical mechanism of linking two cytoskeletal systems together in dissociating the Bb. Instead our results suggest that Macf1a functions by linking one cytoskeletal system, cortical actin, to another structure, the Bb, where Macf1a is localized. Through this novel linking process, it dissociates the Bb at the oocyte cortex, thus specifying the AV axis of the oocyte and future egg. To our knowledge, this is also the first study to use genome editing to unravel the module-dependent function of a cytoskeletal linker. The totipotent egg of most vertebrates is polarized in a so called animal-vegetal axis that is essential to early embryonic development. The animal-vegetal axis is established in the early oocyte by the dissociation of the Balbiani Body (Bb). The Bb is a large RNA-protein granule, conserved from insects to mammals, that forms next to the oocyte nucleus and dissociates later at the oocyte cortex. Importantly, Bb dissociation at the oocyte cortex defines the future vegetal pole of the egg. Macf1a, a cytolinker, is the only factor known to regulate Bb dissociation. However, how the giant Macf1a protein with multiple functional domains can interact with the cytoskeleton to regulate Bb disassembly is unknown. Here, we unravel Macf1a function via interrogating, for the first time, individual macf1a-encoded domains of the gene in its normal chromosomal location for their requirement in Bb dissociation and ultimately in egg polarity establishment. The method presented here is applicable to other cytolinkers involved in human disease.
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Nguyen AL, Marin D, Zhou A, Gentilello AS, Smoak EM, Cao Z, Fedick A, Wang Y, Taylor D, Scott RT, Xing J, Treff N, Schindler K. Identification and characterization of Aurora kinase B and C variants associated with maternal aneuploidy. Mol Hum Reprod 2017; 23:406-416. [PMID: 28369513 PMCID: PMC9915067 DOI: 10.1093/molehr/gax018] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 03/20/2017] [Indexed: 12/16/2022] Open
Abstract
STUDY QUESTION Are single nucleotide variants (SNVs) in Aurora kinases B and C (AURKB, AURKC) associated with risk of aneuploid conception? SUMMARY ANSWER Two SNVs were found in patients with extreme aneuploid concepti rates with respect to their age; one variant, AURKC p.I79V, is benign, while another, AURKB p.L39P, is a potential gain-of-function mutant with increased efficiency in promoting chromosome alignment. WHAT IS KNOWN ALREADY Maternal age does not always predict aneuploidy risk, and rare gene variants can be drivers of disease. The AURKB and AURKC regulate chromosome segregation, and are associated with reproductive impairments in mouse and human. STUDY DESIGN, SIZE, DURATION An extreme phenotype sample selection scheme was performed for variant discovery. Ninety-six DNA samples were from young patients with higher than average embryonic aneuploidy rates and an additional 96 DNA samples were from older patients with lower than average aneuploidy rates. PARTICIPANTS/MATERIALS, SETTING, METHODS Using the192 DNA samples, the coding regions of AURKB and AURKC were sequenced using next generation sequencing. To assess biological significance, we expressed complementary RNA encoding the human variants in mouse oocytes. Assays such as determining subcellular localization and assessing catalytic activity were performed to determine alterations in protein function during meiosis. MAIN RESULTS AND THE ROLE OF CHANCE Ten SNVs were identified using three independent variant-calling methods. Two of the SNVs (AURKB p.L39P and AURKC p.I79V) were non-synonymous and identified by at least two variant-identification methods. The variant encoding AURKC p.I79V, identified in a young woman with a higher than average rate of aneuploid embryos, showed wild-type localization pattern and catalytic activity. On the other hand, the variant encoding AURKB p.L39P, identified in an older woman with lower than average rates of aneuploid embryos, increased the protein's ability to regulate alignment of chromosomes at the metaphase plate. These experiments were repeated three independent times using 2-3 mice for each trial. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION Biological significance of the human variants was assessed in an in vitro mouse oocyte model where the variants are over-expressed. Therefore, the human protein may not function identically to the mouse homolog, or the same in mouse oocytes as in human oocytes. Furthermore, supraphysiological expression levels may not accurately reflect endogenous activity. Moreover, the evaluated variants were identified in one patient each, and no trial linking the SNV to pregnancy outcomes was conducted. Finally, the patient aneuploidy rates were established by performing comprehensive chromosome screening in blastocysts, and because of the link between female gamete aneuploidy giving rise to aneuploid embryos, we evaluate the role of the variants in Meiosis I. However, it is possible that the chromosome segregation mistake arose during Meiosis II or in mitosis in the preimplantation embryo. Their implications in human female meiosis and aneuploidy risk remain to be determined. WIDER IMPLICATIONS OF THE FINDINGS The data provide evidence that gene variants exist in reproductively younger or advanced aged women that are predictive of the risk of producing aneuploid concepti in humans. Furthermore, a single amino acid in the N-terminus of AURKB is a gain-of-function mutant that could be protective of euploidy. STUDY FUNDING/COMPETING INTERESTS This work was supported by a Research Grant from the American Society of Reproductive Medicine and support from the Charles and Johanna Busch Memorial Fund at Rutgers, the State University of NJ to K.S. and the Foundation for Embryonic Competence, Inc to N.T. The authors declare no conflicts of interest.
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Affiliation(s)
| | | | - Anbo Zhou
- Department of Genetics, Rutgers, The State University of New Jersey, 145 Bevier Rd. Piscataway, NJ 08854, USA
| | - Amanda S. Gentilello
- Department of Genetics, Rutgers, The State University of New Jersey, 145 Bevier Rd. Piscataway, NJ 08854, USA
| | - Evan M. Smoak
- Department of Genetics, Rutgers, The State University of New Jersey, 145 Bevier Rd. Piscataway, NJ 08854, USA
| | - Zubing Cao
- Department of Genetics, Rutgers, The State University of New Jersey, 145 Bevier Rd. Piscataway, NJ 08854, USA
| | - Anastasia Fedick
- Department of Genetics, Rutgers, The State University of New Jersey, 145 Bevier Rd. Piscataway, NJ 08854, USA,Reproductive Medicine Associates of New Jersey, 140 Allen Rd, Basking Ridge, NJ 07920, USA
| | - Yujue Wang
- Department of Genetics, Rutgers, The State University of New Jersey, 145 Bevier Rd. Piscataway, NJ 08854, USA,Reproductive Medicine Associates of New Jersey, 140 Allen Rd, Basking Ridge, NJ 07920, USA
| | - Deanne Taylor
- Reproductive Medicine Associates of New Jersey, 140 Allen Rd, Basking Ridge, NJ 07920, USA,
Present address: Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, 3501 Civic Center Blvd, Philadelphia, PA 19104, USA
| | - Richard T. Scott
- Reproductive Medicine Associates of New Jersey, 140 Allen Rd, Basking Ridge, NJ 07920, USA
| | - Jinchuan Xing
- Department of Genetics, Rutgers, The State University of New Jersey, 145 Bevier Rd. Piscataway, NJ 08854, USA
| | - Nathan Treff
- Reproductive Medicine Associates of New Jersey, 140 Allen Rd, Basking Ridge, NJ 07920, USA
| | - Karen Schindler
- Correspondence address. Department of Genetics, Rutgers, The State University of New Jersey, NJ, USA. E-mail:
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Role of Cdc6 During Oogenesis and Early Embryo Development in Mouse and Xenopus laevis. Results Probl Cell Differ 2017; 59:201-211. [PMID: 28247050 DOI: 10.1007/978-3-319-44820-6_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cdc6 is an important player in cell cycle regulation. It is involved in the regulation of both S-phase and M-phase. Its role during oogenesis is crucial for repression of the S-phase between the first and the second meiotic M-phases, and it also regulates, via CDK1 inhibition, the M-phase entry and exit. This is of special importance for the reactivation of the major M-phase-regulating kinase CDK1 (Cyclin-Dependent Kinase 1) in oocytes entering metaphase II of meiosis and in embryo cleavage divisions, in which precise timing allows coordination between cell cycle events and developmental program of the embryo. In this chapter, we discuss the role of Cdc6 protein in oocytes and early embryos.
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11
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Fellmeth JE, Ghanaim EM, Schindler K. Characterization of macrozoospermia-associated AURKC mutations in a mammalian meiotic system. Hum Mol Genet 2016; 25:2698-2711. [PMID: 27106102 DOI: 10.1093/hmg/ddw128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/13/2016] [Accepted: 04/18/2016] [Indexed: 12/12/2022] Open
Abstract
Aneuploidy is the leading genetic abnormality that leads to miscarriage, and it is caused by a failure of accurate chromosome segregation during gametogenesis or early embryonic divisions. Aurora kinase C (AURKC) is essential for formation of euploid sperm in humans because mutations in AURKC are correlated with macrozoospermia and these sperm are tetraploid. These mutations are currently the most frequent mutations that cause macrozoospermia and result from an inability to complete meiosis I (MI). Three of these mutations AURKC c.144delC (AURKC p.L49Wfs22), AURKC c.686G > A (AURKC p.C229Y) and AURKC c.744C > G (AURKC p.Y248*) occur in the coding region of the gene and are the focus of this study. By expressing these alleles in oocytes isolated from Aurkc-/- mice, we show that the mutations have different effects on AURKC function during MI. AURKC p.L49Wfs22 is a loss-of-function mutant that perturbs localization of the chromosomal passenger complex (CPC), AURKC p.C229Y is a hypomorph that cannot fully support cell-cycle progression, and AURKC p.Y248* fails to localize and function with the CPC to support chromosome segregation yet retains catalytic activity in the cytoplasm. Finally, we show that these variants of AURKC cause meiotic failure and polyploidy due to a failure in AURKC-CPC function that results in metaphase chromosome misalignment. This study is the first to assess the function of mutant alleles of AURKC that affect human fertility in a mammalian meiotic system.
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Affiliation(s)
| | - Elena M Ghanaim
- Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA
| | - Karen Schindler
- Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA
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12
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Ma XS, Lin F, Wang ZW, Hu MW, Huang L, Meng TG, Jiang ZZ, Schatten H, Wang ZB, Sun QY. Geminin deletion in mouse oocytes results in impaired embryo development and reduced fertility. Mol Biol Cell 2016; 27:768-75. [PMID: 26764091 PMCID: PMC4803303 DOI: 10.1091/mbc.e15-06-0346] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 01/06/2016] [Indexed: 12/28/2022] Open
Abstract
Geminin is an important regulator of DNA replication and cell differentiation, but its role in female reproduction remains uncertain. Maternal geminin does not regulate oocyte meiotic maturation but does control accurate DNA replication. Geminin deletion in oocytes results in impaired embryo development and reduced fertility. Geminin controls proper centrosome duplication, cell division, and differentiation. We investigated the function of geminin in oogenesis, fertilization, and early embryo development by deleting the geminin gene in oocytes from the primordial follicle stage. Oocyte-specific disruption of geminin results in low fertility in mice. Even though there was no evident anomaly of oogenesis, oocyte meiotic maturation, natural ovulation, or fertilization, early embryo development and implantation were impaired. The fertilized eggs derived from mutant mice showed developmental delay, and many were blocked at the late zygote stage. Cdt1 protein was decreased, whereas Chk1 and H2AX phosphorylation was increased, in fertilized eggs after geminin depletion. Our results suggest that disruption of maternal geminin may decrease Cdt1 expression and cause DNA rereplication, which then activates the cell cycle checkpoint and DNA damage repair and thus impairs early embryo development.
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Affiliation(s)
- Xue-Shan Ma
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Fei Lin
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhong-Wei Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Meng-Wen Hu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China University of Chinese Academy of Sciences, Beijing 100101, China
| | - Lin Huang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tie-Gang Meng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China University of Chinese Academy of Sciences, Beijing 100101, China
| | - Zong-Zhe Jiang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211
| | - Zhen-Bo Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qing-Yuan Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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13
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Fellmeth JE, Gordon D, Robins CE, Scott RT, Treff NR, Schindler K. Expression and characterization of three Aurora kinase C splice variants found in human oocytes. Mol Hum Reprod 2015; 21:633-44. [PMID: 25995441 PMCID: PMC4518136 DOI: 10.1093/molehr/gav026] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/14/2015] [Indexed: 12/31/2022] Open
Abstract
Chromosome segregation is an extensively choreographed process yet errors still occur frequently in female meiosis, leading to implantation failure, miscarriage or offspring with developmental disorders. Aurora kinase C (AURKC) is a component of the chromosome passenger complex and is highly expressed in gametes. Studies in mouse oocytes indicate that AURKC is required to regulate chromosome segregation during meiosis I; however, little is known about the functional significance of AURKC in human oocytes. Three splice variants of AURKC exist in testis tissue. To determine which splice variants human oocytes express, we performed quantitative real-time PCR using single oocytes and found expression of all three variants. To evaluate the functional differences between the variants, we created green fluorescent protein-tagged constructs of each variant to express in oocytes from Aurkc(-/-) mice. By quantifying metaphase chromosome alignment, cell cycle progression, phosphorylation of INCENP and microtubule attachments to kinetochores, we found that AURKC_v1 was the most capable of the variants at supporting metaphase I chromosome segregation. AURKC_v3 localized to chromosomes properly and supported cell cycle progression to metaphase II, but its inability to correct erroneous microtubule attachments to kinetochores meant that chromosome segregation was not as accurate compared with the other two variants. Finally, when we expressed the three variants simultaneously, error correction was more robust than when they were expressed on their own. Therefore, oocytes express three variants of AURKC that are not functionally equivalent in supporting meiosis, but fully complement meiosis when expressed simultaneously.
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Affiliation(s)
- Jessica E Fellmeth
- Department of Genetics, Rutgers University, 145 Bevier Road, Piscataway, NJ 08854, USA
| | - Derek Gordon
- Department of Genetics, Rutgers University, 145 Bevier Road, Piscataway, NJ 08854, USA
| | - Christian E Robins
- Reproductive Medicine Associates of New Jersey, Basking Ridge, NJ 07960, USA
| | - Richard T Scott
- Reproductive Medicine Associates of New Jersey, Basking Ridge, NJ 07960, USA
| | - Nathan R Treff
- Department of Genetics, Rutgers University, 145 Bevier Road, Piscataway, NJ 08854, USA Reproductive Medicine Associates of New Jersey, Basking Ridge, NJ 07960, USA
| | - Karen Schindler
- Department of Genetics, Rutgers University, 145 Bevier Road, Piscataway, NJ 08854, USA
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14
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Daldello EM, Le T, Poulhe R, Jessus C, Haccard O, Dupré A. Fine-tuning of Cdc6 accumulation by Cdk1 and MAP kinase is essential for completion of oocyte meiotic divisions. J Cell Sci 2015; 128:2482-96. [DOI: 10.1242/jcs.166553] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 05/19/2015] [Indexed: 01/28/2023] Open
Abstract
Vertebrate oocytes proceed through the 1st and the 2nd meiotic division without intervening S-phase to become haploid. Although DNA replication does not take place, unfertilized oocytes acquire the competence to replicate DNA one hour after the 1st meiotic division, by accumulating an essential factor of the replicative machinery, Cdc6. Here, we discovered that the turnover of Cdc6 is precisely regulated in oocytes to avoid inhibition of Cdk1. At meiosis resumption, Cdc6 starts to be expressed but cannot accumulate due to a degradation mechanism activated through Cdk1. During transition from 1st to 2nd meiotic division, Cdc6 is under antagonistic regulation of Cyclin B, whose interaction with Cdc6 stabilizes the protein, and Mos/MAPK that negatively controls its accumulation. Since overexpressing Cdc6 inhibits Cdk1 reactivation and drives oocytes into a replicative interphasic state, the fine-tuning of Cdc6 accumulation is essential to ensure two meiotic waves of Cdk1 activation and to avoid unscheduled DNA replication during meiotic maturation.
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Affiliation(s)
- Enrico M. Daldello
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
| | - Tran Le
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
| | - Robert Poulhe
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
| | - Catherine Jessus
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
| | - Olivier Haccard
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
| | - Aude Dupré
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
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15
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El Dika M, Laskowska-Kaszub K, Koryto M, Dudka D, Prigent C, Tassan JP, Kloc M, Polanski Z, Borsuk E, Kubiak JZ. CDC6 controls dynamics of the first embryonic M-phase entry and progression via CDK1 inhibition. Dev Biol 2014; 396:67-80. [DOI: 10.1016/j.ydbio.2014.09.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 09/18/2014] [Accepted: 09/19/2014] [Indexed: 11/29/2022]
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16
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Liu W, Stein P, Cheng X, Yang W, Shao NY, Morrisey EE, Schultz RM, You J. BRD4 regulates Nanog expression in mouse embryonic stem cells and preimplantation embryos. Cell Death Differ 2014; 21:1950-60. [PMID: 25146928 DOI: 10.1038/cdd.2014.124] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/10/2014] [Accepted: 07/13/2014] [Indexed: 01/06/2023] Open
Abstract
Bromodomain-containing protein 4 (BRD4) is an important epigenetic reader implicated in the pathogenesis of a number of different cancers and other diseases. Brd4-null mouse embryos die shortly after implantation and are compromised in their ability to maintain the inner cell mass, which gives rise to embryonic stem cells (ESCs). Here we report that BRD4 regulates expression of the pluripotency factor Nanog in mouse ESCs and preimplantation embryos, as well as in human ESCs and embryonic cancer stem cells. Inhibition of BRD4 function using a chemical inhibitor, small interfering RNAs, or a dominant-negative approach suppresses Nanog expression, and abolishes the self-renewal ability of ESCs. We also find that BRD4 associates with BRG1 (brahma-related gene 1, aka Smarca4 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 4)), a key regulator of ESC self-renewal and pluripotency, in the Nanog regulatory regions to regulate Nanog expression. Our study identifies Nanog as a novel BRD4 target gene, providing new insights for the biological function of BRD4 in stem cells and mouse embryos. Knowledge gained from these non-cancerous systems will facilitate future investigations of how Brd4 dysfunction leads to cancers.
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Affiliation(s)
- W Liu
- Department of Microbiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - P Stein
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - X Cheng
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - W Yang
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - N-Y Shao
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - E E Morrisey
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - R M Schultz
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - J You
- Department of Microbiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
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17
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Histone deacetylase 2 (HDAC2) regulates chromosome segregation and kinetochore function via H4K16 deacetylation during oocyte maturation in mouse. PLoS Genet 2013; 9:e1003377. [PMID: 23516383 PMCID: PMC3597510 DOI: 10.1371/journal.pgen.1003377] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 01/29/2013] [Indexed: 01/26/2023] Open
Abstract
Changes in histone acetylation occur during oocyte development and maturation, but the role of specific histone deacetylases in these processes is poorly defined. We report here that mice harboring Hdac1−/+/Hdac2−/− or Hdac2−/− oocytes are infertile or sub-fertile, respectively. Depleting maternal HDAC2 results in hyperacetylation of H4K16 as determined by immunocytochemistry—normal deacetylation of other lysine residues of histone H3 or H4 is observed—and defective chromosome condensation and segregation during oocyte maturation occurs in a sub-population of oocytes. The resulting increased incidence of aneuploidy likely accounts for the observed sub-fertility of mice harboring Hdac2−/− oocytes. The infertility of mice harboring Hdac1−/+/Hdac2−/−oocytes is attributed to failure of those few eggs that properly mature to metaphase II to initiate DNA replication following fertilization. The increased amount of acetylated H4K16 likely impairs kinetochore function in oocytes lacking HDAC2 because kinetochores in mutant oocytes are less able to form cold-stable microtubule attachments and less CENP-A is located at the centromere. These results implicate HDAC2 as the major HDAC that regulates global histone acetylation during oocyte development and, furthermore, suggest HDAC2 is largely responsible for the deacetylation of H4K16 during maturation. In addition, the results provide additional support that histone deacetylation that occurs during oocyte maturation is critical for proper chromosome segregation. Oocyte development is becoming of increasing interest not only in the broad research community but also within the general public due, in part, to the ever increasing demand for and use of assisted reproductive technologies (ART) to treat human infertility, and because the oocyte-to-embryo transition encompasses a natural reprogramming of gene expression, a process central to forming iPS cells. Dramatic changes in chromatin structure and gene expression occur during oocyte development, but the role of such changes in generating oocytes that are capable of maturing, being fertilized, and giving rise to offspring is very poorly understood. Histone deacetylases (HDACs) are critically involved in modulating chromatin structure. Here, we describe the effect of specifically deleting the gene encoding Hdac2 in mouse oocytes and find the fertility of female mice harboring such oocytes is compromised. Although such mutant oocytes can grow they fail to mature properly to become an egg. The primary defect is that histone H4 acetylated on lysine 16 fails to become deacetylated as the oocyte matures to become an egg, with the consequence that the ability of chromosomes to interact with spindle microtubules is compromised, which in turn leads to improper chromosome segregation.
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18
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Ma J, Flemr M, Strnad H, Svoboda P, Schultz RM. Maternally recruited DCP1A and DCP2 contribute to messenger RNA degradation during oocyte maturation and genome activation in mouse. Biol Reprod 2013; 88:11. [PMID: 23136299 DOI: 10.1095/biolreprod.112.105312] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The oocyte-to-zygote transition entails transforming a highly differentiated oocyte into totipotent blastomeres and represents one of the earliest obstacles that must be successfully hurdled for continued development. Degradation of maternal mRNAs, which likely lies at the heart of this transition, is characterized by a transition from mRNA stability to instability during oocyte maturation. Although phosphorylation of the oocyte-specific RNA-binding protein MSY2 during maturation is implicated in making maternal mRNAs more susceptible to degradation, mechanisms underlying mRNA degradation during oocyte maturation remain poorly understood. We report that DCP1A and DCP2, proteins responsible for decapping mRNA, are encoded by maternal mRNAs recruited for translation during maturation via cytoplasmic polyadenylation elements located in their 3' untranslated regions. Both DCP1A and DCP2 are phosphorylated during maturation, with CDC2A being the kinase likely responsible for both, although MAPK may be involved in DCP1A phosphorylation. Inhibiting accumulation of DCP1A and DCP2 by RNA interference or morpholinos decreases not only degradation of mRNAs during meiotic maturation but also transcription of the zygotic genome. The results indicate that maternally recruited DCP1A and DCP2 are critical players in the transition from mRNA stability to instability during meiotic maturation and that proper maternal mRNA degradation must be successful to execute the oocyte-to-zygote transition.
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Affiliation(s)
- Jun Ma
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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19
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Toralová T, Benešová V, Kepková KV, Vodička P, Šušor A, Kaňka J. Bovine preimplantation embryos with silenced nucleophosmin mRNA are able to develop until the blastocyst stage. Reproduction 2012; 144:349-59. [DOI: 10.1530/rep-12-0033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This study was conducted to investigate the effect of silencing nucleophosmin in the development of in vitro-produced bovine embryos. Nucleophosmin is an abundant multifunctional nucleolar phosphoprotein that participates, for example, in ribosome biogenesis or centrosome duplication control. We showed that although the transcription of embryonic nucleophosmin started already at late eight-cell stage, maternal protein was stored throughout the whole preimplantation development and was sufficient for the progression to the blastocyst stage. At the beginning of embryogenesis, translation occurs on maternally derived ribosomes, the functionally active nucleoli emerge during the fourth cell cycle in bovines. We found that nucleophosmin localisation reflected the nucleolar formation during bovine preimplantation development. The protein was detectable from the beginning of embryonic development. Before embryonic genome activation, it was dispersed throughout the nucleoplasm. The typical nucleolar localisation emerged with the formation of active nucleoli. At the blastocyst stage, nucleophosmin tended to localise especially to the trophectoderm. To see for how long is maternal nucleophosmin preserved, we silenced the nucleophosmin mRNA using RNA interference approach. Although a large portion of nucleophosmin was degraded in embryos with silenced nucleophosmin mRNA, an amount sufficient for normal development was preserved and we detected only a temporal delay in nucleophosmin relocalisation to nucleoli. Moreover, we observed no defects in nuclear shape or cytoskeleton previously found in somatic cells and only a non-significant decrease in embryonic developmental competence. Thus, our results show that the preserved amount of maternal nucleophosmin is sufficient for preimplantation development of bovine embryo.
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Xia M, He H, Wang Y, Liu M, Zhou T, Lin M, Zhou Z, Huo R, Zhou Q, Sha J. PCBP1 is required for maintenance of the transcriptionally silent state in fully grown mouse oocytes. Cell Cycle 2012; 11:2833-42. [PMID: 22801551 DOI: 10.4161/cc.21169] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Global transcriptional silencing in fully grown oocytes is a critical event during mammalian oogenesis. However, how this event is regulated remains elusive. Here, we provide evidence that poly(rC)-binding protein 1 (PCBP1), a protein found by us previously to be present in metaphase II (MII) mouse oocytes, participates in maintenance of the transcriptionally silent state in fully grown mouse oocytes. Knocking down Pcbp1 by microinjection of its specific siRNAs into fully grown germinal vesicle (GV) oocytes resulted in remarkable changes in their transcriptional state, including the disequilibrium between the number of oocytes with an NSN (non-surrounded nucleolus) and those with a SN (surrounded nucleolus), and obvious transcriptional reactiviation in oocytes with a SN configuration as evidenced by BrUTP incorporation assay and immunofluorescent labeling of phosphorylated RNA polymerase II CTD and trimethylated H3 lysine 4, markers for active transcription. Furthermore, in a comprehensive microarray analysis of the preovulatory oocyte transcriptome, an incredible number of nearly 4,000 transcripts were upregulated in the Pcbp1 knockdown groups. These data indicate that lack of the function of PCBP1 disrupts the quiescent status of transcription in the fully grown oocytes, and hence supporting a role of this protein in the regulation of global transcriptional silcencing in fully grown mouse oocytes.
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Affiliation(s)
- Meng Xia
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Nanjing Medical University, Nanjing, China
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21
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Maternally recruited Aurora C kinase is more stable than Aurora B to support mouse oocyte maturation and early development. Proc Natl Acad Sci U S A 2012; 109:E2215-22. [PMID: 22778418 DOI: 10.1073/pnas.1120517109] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Aurora kinases are highly conserved, essential regulators of cell division. Two Aurora kinase isoforms, A and B (AURKA and AURKB), are expressed ubiquitously in mammals, whereas a third isoform, Aurora C (AURKC), is largely restricted to germ cells. Because AURKC is very similar to AURKB, based on sequence and functional analyses, why germ cells express AURKC is unclear. We report that Aurkc(-/-) females are subfertile, and that AURKB function declines as development progresses based on increasing severity of cytokinesis failure and arrested embryonic development. Furthermore, we find that neither Aurkb nor Aurkc is expressed after the one-cell stage, and that AURKC is more stable during maturation than AURKB using fluorescently tagged reporter proteins. In addition, Aurkc mRNA is recruited during maturation. Because maturation occurs in the absence of transcription, posttranscriptional regulation of Aurkc mRNA, coupled with the greater stability of AURKC protein, provides a means to ensure sufficient Aurora kinase activity, despite loss of AURKB, to support both meiotic and early embryonic cell divisions. These findings suggest a model for the presence of AURKC in oocytes: that AURKC compensates for loss of AURKB through differences in both message recruitment and protein stability.
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22
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Narasimhachar Y, Webster DR, Gard DL, Coué M. Cdc6 is required for meiotic spindle assembly in Xenopus oocytes. Cell Cycle 2012; 11:524-31. [PMID: 22262174 DOI: 10.4161/cc.11.3.19033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
During the maturation of Xenopus oocytes, Cdc6 expression is necessary to establish replication competence to support early embryonic DNA replication. However, Cdc6 is expressed before the completion of MI, at a time when its function as a replication factor is not required, suggesting additional roles for Cdc6 in meiosis. Confocal immunofluorescence microscopy revealed that Cdc6 protein was distributed around the spindle precursor at the time of germinal vesicle breakdown (GVBD), and localized to the margin of the nascent spindle early in prometaphase. Cdc6 subsequently localized to spindle poles in late prometaphase, where it remained until metaphase arrest. Microinjection of antisense oligonucleotides specific for Cdc6 mRNA disrupted spindle assembly, resulting in defects including delayed spindle assembly, misoriented and unattached anaphase spindles, monasters, multiple spindles, microtubule aggregates associated with condensed chromosomes, or the absence of recognizable spindle-like structures, depending on the level of residual Cdc6 expression. Furthermore, Cdc6 co-localized with γ-tubulin in centrosomes during interphase in all somatic cells analyzed, and associated with spindle poles in mitotic COS cells. Our data suggest a role for Cdc6 in spindle formation in addition to its role as a DNA replication factor.
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Affiliation(s)
- Yadushyla Narasimhachar
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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23
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Murai S, Stein P, Buffone MG, Yamashita S, Schultz RM. Recruitment of Orc6l, a dormant maternal mRNA in mouse oocytes, is essential for DNA replication in 1-cell embryos. Dev Biol 2010; 341:205-12. [PMID: 20219456 DOI: 10.1016/j.ydbio.2010.02.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 02/18/2010] [Accepted: 02/19/2010] [Indexed: 01/08/2023]
Abstract
Mouse oocytes acquire the ability to replicate DNA during meiotic maturation, presumably to ensure that DNA replication does not occur precociously between MI and MII and only after fertilization. Acquisition of DNA replication competence requires protein synthesis, but the identity of the proteins required for DNA replication is poorly described. In Xenopus, the only component missing for DNA replication competence is CDC6, which is synthesized from a dormant maternal mRNA recruited during oocyte maturation, and a similar situation also occurs during mouse oocyte maturation. We report that ORC6L is another component required for acquisition of DNA replication competence that is absent in mouse oocytes. The dormant maternal Orc6l mRNA is recruited during maturation via a CPE present in its 3' UTR. RNAi-mediated ablation of maternal Orc6l mRNA prevents the maturation-associated increase in ORC6L protein and inhibits DNA replication in 1-cell embryos. These results suggest that mammalian oocytes have more complex mechanisms to establish DNA replication competence when compared to their Xenopus counterparts.
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Affiliation(s)
- Shin Murai
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA.
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24
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Lee HS, Kim EY, Kim KH, Moon J, Park KS, Kim KS, Lee KA. Obox4 critically regulates cAMP-dependent meiotic arrest and MI-MII transition in oocytes. FASEB J 2010; 24:2314-24. [PMID: 20154267 DOI: 10.1096/fj.09-147314] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Extra follicular oocytes spontaneously resume meiosis in vitro, but the intact germinal vesicle (GV) is retained if the oocytes are cultured in medium containing phosphodiesterase (PDE) inhibitors or cAMP analogues. On the basis of our finding that Obox4 is prominently expressed in oocytes, the present study was conducted to determine the functional role of the homeodomain-containing factor Obox4 during in vitro oocyte maturation. After microinjection of Obox4 dsRNA into the cytoplasm of GV oocytes cultured in M16 medium, oocytes were arrested at metaphase I (MI, 77.7%) and metaphase II (MII, 22.3%). Surprisingly, however, 89% of Obox4 RNAi-treated oocytes resumed meiosis and developed to MI and MII when cultured in medium containing 0.2 mM 3-isobutyl-1-methyl-xanthine (IBMX), in which untreated oocytes maintain intact GVs. Spindles were aberrant, and chromosomes were severely aggregated with decreased MPF and MAP kinase activities in arrested MI oocytes after exposure to Obox4 RNAi. Oocytes overexpressing Obox4 retained intact GVs when cultured in M16 medium. Taken together, for the first time to our knowledge, these findings indicate that Obox4 plays a key role in the cAMP-dependent signaling cascades that maintain GV arrest. Oocytes not expressing Obox4 failed to maintain intact GVs in IBMX-supplemented medium, while GVs remained intact when oocytes were kept in plain medium and overexpressing Obox4, suggesting that Obox4 plays a critical role in cAMP-dependent cascade for maintaining intact GVs.
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Affiliation(s)
- Hyun-Seo Lee
- Department of Biomedical Science, College of Life Science, CHA University, 606-13 Yeoksam-1- dong, Gangnam-gu, Seoul 135-081, Korea
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Toralová T, Susor A, Nemcová L, Kepková K, Kanka J. Silencing CENPF in bovine preimplantation embryo induces arrest at 8-cell stage. Reproduction 2009; 138:783-91. [PMID: 19651849 DOI: 10.1530/rep-09-0234] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Identification of genes that are important for normal preimplantation development is essential for understanding the basics of early mammalian embryogenesis. In our previous study, we have shown that CENPF (mitosin) is differentially expressed during preimplantation development of bovine embryos. CENPF is a centromere-kinetochore complex protein that plays a crucial role in the cell division of somatic cells. To our best knowledge, no study has yet been done on either bovine model, or oocytes and preimplantation embryos. In this study, we focused on the fate of bovine embryos after injection of CENPF double-stranded RNA (dsRNA) into the zygotes. An average decrease of CENPF mRNA abundance by 94.9% or more and an extensive decline in immunofluorescence staining intensity was detected relative to controls. There was no disparity between individual groups in the developmental competence before the 8-cell stage. However, the developmental competence rapidly decreased then and only 28.1% of CENPF dsRNA injected 8-cell embryos were able to develop further (uninjected control: 71.8%; green fluorescent protein dsRNA injected control: 72.0%). In conclusion, these results show that depletion of CENPF mRNA in preimplantation bovine embryos leads to dramatic decrease of developmental competence after embryonic genome activation.
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Affiliation(s)
- Tereza Toralová
- Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, vvi, Academy of Sciences of the Czech Republic, Libechov, Czech Republic.
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26
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Metchat A, Akerfelt M, Bierkamp C, Delsinne V, Sistonen L, Alexandre H, Christians ES. Mammalian heat shock factor 1 is essential for oocyte meiosis and directly regulates Hsp90alpha expression. J Biol Chem 2009; 284:9521-8. [PMID: 19158073 DOI: 10.1074/jbc.m808819200] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heat shock transcription factor 1 (HSF1) is the main regulator of the stress response that triggers the transcription of several genes encoding heat shock proteins (Hsps). Hsps act as molecular chaperones involved in protein folding, stability, and trafficking. HSF1 is highly expressed in oocytes and Hsf1 knock-out in mice revealed that in the absence of stress this factor plays an important role in female reproduction. We previously reported that Hsf1(-/-) females produce oocytes but no viable embryos. Consequently, we asked whether oocytes require HSF1 to regulate a particular set of Hsps necessary for them to develop. We find that Hsp90alpha (Hspaa1) is the major HSF1-dependent chaperone inasmuch as Hsf1 knock-out resulted in Hsp90-depleted oocytes. These oocytes exhibited delayed germinal vesicle breakdown (or G(2)/M transition), partial meiosis I block, and defective asymmetrical division. To probe the role of Hsp90alpha in this meiotic syndrome, we analyzed meiotic maturation in wild-type oocytes treated with a specific inhibitor of Hsp90, 17-allylamino-17-demethoxy-geldanamycin, and observed similar defects. At the molecular level we showed that, together with these developmental anomalies, CDK1 and MAPK, key meiotic kinases, were significantly disturbed. Thus, our data demonstrate that HSF1 is a maternal transcription factor essential for normal progression of meiosis.
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Affiliation(s)
- Aïcha Metchat
- UPS, Centre de Biologie du Développement-UMR5547, 4R3B3, Université de Toulouse, 118 route de Narbonne, F-31062 Toulouse, France
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27
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Ihara M, Stein P, Schultz RM. UBE2I (UBC9), a SUMO-conjugating enzyme, localizes to nuclear speckles and stimulates transcription in mouse oocytes. Biol Reprod 2008; 79:906-13. [PMID: 18703419 DOI: 10.1095/biolreprod.108.070474] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Sumoylation is a posttranslational modification in which SUMO (small ubiquitin-related modifier) proteins are covalently attached to their substrates. In vertebrates, developmental roles for sumoylation have been studied, but the function of sumoylation during mammalian oocyte growth and maturation is not known. As a prelude to conducting studies on the role of sumoylation during oocyte development, we analyzed the temporal and spatial pattern of expression of UBE2I, a SUMO-conjugating E2 enzyme. Immunocytochemical analysis of UBE2I revealed a punctate nuclear staining pattern, with transcriptionally quiescent, fully grown, GV-intact oocytes having larger UBE2I-containing bodies than transcriptionally active, meiotically incompetent growing oocytes. Inhibiting transcription in incompetent oocytes resulted in an increase in the size of the UBE2I-containing bodies. Overexpression of either wild-type UBE2I or catalytically inactive UBE2I resulted in an increase in the size of the UBE2I-containing bodies but also an increase in BrUTP incorporation, suggesting that transcriptional activation by UBE2I is independent of its catalytic activity. Although UBE2I-containing bodies did not completely colocalize with SUMO1 or SUMO2 and SUMO3, which were localized mainly on the nuclear membrane and in the nucleoplasm, UBE2I strikingly colocalized with SFRS2, which is a component of nuclear speckles and critical for mRNA processing. These results suggest a novel function for UBE2I and therefore sumoylation in gene expression.
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Affiliation(s)
- Motomasa Ihara
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018, USA
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28
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Abstract
Although approximately 1 in 10,000 animal species is capable of parthenogenetic reproduction, the evolutionary causes and consequences of such transitions remain uncertain. The microcrustacean Daphnia pulex provides a potentially powerful tool for investigating these issues because lineages that are obligately asexual in terms of female function can nevertheless transmit meiosis-suppressing genes to sexual populations via haploid sperm produced by environmentally induced males. The application of association mapping to a wide geographic collection of D. pulex clones suggests that sex-limited meiosis suppression in D. pulex has spread westward from a northeastern glacial refugium, conveyed by a dominant epistatic interaction among the products of at least four unlinked loci, with one entire chromosome being inherited through males in a nearly nonrecombining fashion. With the enormous set of genomic tools now available for D. pulex, these results set the stage for the determination of the functional underpinnings of the conversion of meiosis to a mitotic-like mode of inheritance.
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Age-associated increase in aneuploidy and changes in gene expression in mouse eggs. Dev Biol 2008; 316:397-407. [PMID: 18342300 DOI: 10.1016/j.ydbio.2008.01.048] [Citation(s) in RCA: 215] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 01/31/2008] [Accepted: 01/31/2008] [Indexed: 11/21/2022]
Abstract
An increase in the incidence of aneuploidy is well documented with increasing maternal age, in particular in human females. Remarkably, little is known regarding the underlying molecular basis for the age-associated increase in aneuploidy, which is a major source of decreased fertility in humans. Using mouse as a model system we find that eggs obtained from old mice (60-70 weeks of age) display a 6-fold increase in the incidence of hyperploidy as assessed by chromosome spreads. Expression profiling of transcripts in oocytes and eggs obtained from young and old mice reveals that approximately 5% of the transcripts are differentially expressed in oocytes obtained from old females when compared to oocytes obtained from young females (6-12 weeks of age) and that this fraction increases to approximately 33% in eggs. The latter finding indicates that the normal pattern of degradation of maternal mRNAs that occurs during oocyte maturation is dramatically altered in eggs obtained from old mice and could therefore be a contributing source to the decline in fertility. Analysis of the differentially expressed transcripts also indicated that the strength of the spindle assembly checkpoint is weakened and that higher errors of microtubule-kinetochore interactions constitute part of molecular basis for the age-associated increase in aneuploidy in females. Last, BRCA1 expression is reduced in oocytes obtained from old females and RNAi-mediated reduction of BRCA1 in oocytes obtained from young females results in perturbing spindle formation and chromosome congression following maturation.
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30
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Abstract
RNA silencing is a common term for homology-dependent silencing phenomena found in the majority of eukaryotic species. RNA silencing pathways share several conserved components. The common denominator of these pathways is the presence of specific, short (21-25 nt) RNA molecules generated from different double-stranded RNA substrates by a specific RNase III activity. Short RNA molecules serve as a template for sequence-specific effects including transcriptional silencing, mRNA degradation, and inhibition of translation. This review will discuss possible roles of RNA silencing pathways in mouse oocytes and early embryos as well as the use of RNA silencing for experimental inhibition of gene expression in this model system.
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Lau E, Tsuji T, Guo L, Lu SH, Jiang W. The role of pre‐replicative complex (pre‐RC) components in oncogenesis. FASEB J 2007; 21:3786-94. [PMID: 17690155 DOI: 10.1096/fj.07-8900rev] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Normal DNA replication is stringently regulated to ensure a timely occurrence no more than once per cell cycle. Abrogation of the exquisite control mechanisms that maintain this process results in detrimental gains and losses of genomic DNA commonly seen in cancer and developmental defects. Replication initiation proteins, known as prereplicative complex (pre-RC) proteins, serve as a primary level of regulation, controlling when DNA replication can begin. Unsurprisingly, several pre-RC proteins are overexpressed in cancer and serve as good tumor markers. However, their direct correlation with increasing tumor grade and poor prognosis has posed a long-standing question: Are pre-RC proteins oncogenic? Recently, a growing body of data indicates that deregulation of individual pre-RC proteins, either by overexpression or functional deficiency in several organismal models, results in significant and consistently perturbed cell cycle regulation, genomic instability, and, potentially, tumorigenesis. In this review, we examine this broad range of evidence suggesting that pre-RC proteins play roles during oncogenesis that are more than simply indicative of proliferation, supporting the notion that pre-RC proteins may potentially have significant diagnostic and therapeutic value.
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Affiliation(s)
- Eric Lau
- The Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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32
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Murchison EP, Stein P, Xuan Z, Pan H, Zhang MQ, Schultz RM, Hannon GJ. Critical roles for Dicer in the female germline. Genes Dev 2007; 21:682-93. [PMID: 17369401 PMCID: PMC1820942 DOI: 10.1101/gad.1521307] [Citation(s) in RCA: 372] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Dicer is an essential component of RNA interference (RNAi) pathways, which have broad functions in gene regulation and genome organization. Probing the consequences of tissue-restricted Dicer loss in mice indicates a critical role for Dicer during meiosis in the female germline. Mouse oocytes lacking Dicer arrest in meiosis I with multiple disorganized spindles and severe chromosome congression defects. Oogenesis and early development are times of significant post-transcriptional regulation, with controlled mRNA storage, translation, and degradation. Our results suggest that Dicer is essential for turnover of a substantial subset of maternal transcripts that are normally lost during oocyte maturation. Furthermore, we find evidence that transposon-derived sequence elements may contribute to the metabolism of maternal transcripts through a Dicer-dependent pathway. Our studies identify Dicer as central to a regulatory network that controls oocyte gene expression programs and that promotes genomic integrity in a cell type notoriously susceptible to aneuploidy.
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Affiliation(s)
- Elizabeth P. Murchison
- Cold Spring Harbor Laboratory, Watson School of Biological Sciences and Howard Hughes Medical Institute, Cold Spring Harbor, New York 11724, USA
| | - Paula Stein
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Zhenyu Xuan
- Cold Spring Harbor Laboratory, Watson School of Biological Sciences and Howard Hughes Medical Institute, Cold Spring Harbor, New York 11724, USA
| | - Hua Pan
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Michael Q. Zhang
- Cold Spring Harbor Laboratory, Watson School of Biological Sciences and Howard Hughes Medical Institute, Cold Spring Harbor, New York 11724, USA
| | - Richard M. Schultz
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- E-MAIL ; FAX (215) 898-8780
| | - Gregory J. Hannon
- Cold Spring Harbor Laboratory, Watson School of Biological Sciences and Howard Hughes Medical Institute, Cold Spring Harbor, New York 11724, USA
- Corresponding authors.E-MAIL ; FAX (516) 367-8874
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Romanova LG, Anger M, Zatsepina OV, Schultz RM. Implication of nucleolar protein SURF6 in ribosome biogenesis and preimplantation mouse development. Biol Reprod 2006; 75:690-6. [PMID: 16855206 DOI: 10.1095/biolreprod.106.054072] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The step-wise assembly of a functional nucleolus, which occurs over the first few cell cycles during preimplantation development, is poorly understood. In this study, we examined the function of the evolutionary conserved nucleolar protein SURF6 in preimplantation mouse embryo development. Immunocytochemical analyses revealed that the localization of SURF6 was similar but not identical to those of fibrillarin and B23/nucleophosmin 1, which are involved in rRNA processing and ribosome biogenesis in mammalian somatic cells. Surf6 mRNA, which is expressed in oocytes and maternally inherited in the zygote, reached a peak level of expression during the 8-cell stage of embryo development, at which time rDNA is highly transcribed. Knock-down of Surf6 mRNA by RNAi led to a decrease in both the mRNA and protein levels, and resulted in developmental arrest at the 8-cell/morula stage, as well as a decrease in the level of 18S rRNA. These results suggest that Surf6 is essential for mouse preimplantation development, presumably by regulating ribosome biogenesis.
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Affiliation(s)
- Ludmila G Romanova
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018, USA
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Mehlmann LM. Oocyte-specific expression of Gpr3 is required for the maintenance of meiotic arrest in mouse oocytes. Dev Biol 2005; 288:397-404. [PMID: 16289135 PMCID: PMC1868506 DOI: 10.1016/j.ydbio.2005.09.030] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 09/06/2005] [Accepted: 09/14/2005] [Indexed: 11/26/2022]
Abstract
The maintenance of meiotic prophase arrest in mouse oocytes within fully grown follicles, prior to the surge of luteinizing hormone (LH) that triggers meiotic resumption, depends on a high level of cAMP within the oocyte. cAMP is produced within the oocyte, at least in large part, by the G(s)-linked G-protein-coupled receptor, GPR3. Gpr3 is localized in the mouse oocyte but is also present throughout the follicle. To investigate whether Gpr3 in the follicle cells contributes to the maintenance of meiotic arrest, RNA interference (RNAi) was used to reduce the amount of Gpr3 RNA within follicle-enclosed oocytes. Follicle-enclosed oocytes injected with small interfering double-stranded RNA (siRNA) targeting Gpr3, but not control siRNAs, stimulated the resumption of meiosis in the majority of oocytes following a 3-day culture period. Reduction of RNA was specific for Gpr3 because an unrelated gene was not reduced by microinjection of siRNA. Meiotic resumption was stimulated in isolated oocytes injected with the same siRNA and cultured for 1 to 2 days, but at a much lower rate than in follicle-enclosed oocytes that could be cultured for longer. These results demonstrate that GPR3 specifically in the oocyte, rather than in the follicle cells, is responsible for maintenance of meiotic arrest in mouse oocytes. Furthermore, the method developed here for specifically reducing RNA in follicle-enclosed oocytes, which can be cultured for a sufficient time to reduce the level of endogenous protein, should be generally useful for targeting a wide range of other proteins that may be involved in meiotic arrest, the resumption of meiosis, fertilization, or early embryonic development.
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Affiliation(s)
- Lisa M Mehlmann
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06032, USA.
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Pan H, O'brien MJ, Wigglesworth K, Eppig JJ, Schultz RM. Transcript profiling during mouse oocyte development and the effect of gonadotropin priming and development in vitro. Dev Biol 2005; 286:493-506. [PMID: 16168984 DOI: 10.1016/j.ydbio.2005.08.023] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Revised: 08/09/2005] [Accepted: 08/11/2005] [Indexed: 10/25/2022]
Abstract
The molecular basis for acquisition of meiotic and developmental competence, the two main outcomes of oocyte development and essential for producing an egg capable of being fertilized and supporting development to term, is largely unknown. Using microarrays, we characterized global changes in gene expression in oocytes derived from primordial, primary, secondary, small antral, and large antral follicles and used Expression Analysis Systematic Explorer (EASE) to identify biological and molecular processes that accompany these transitions and likely underpin acquisition of meiotic and developmental competence. The greatest degree of change in gene expression occurs during the primordial to primary follicle transition. Of particular interest is that specific chromosomes display significant changes in their overall transcriptional activity and that in some cases these changes are largely confined to specific regions on these chromosomes. We also examined the transcript profile of oocytes that developed in vitro, as well as following eCG priming. Remarkably, the expression profiles only differed by 4% and 2% from oocytes that developed in vivo when compared to oocytes that developed in vitro from either primordial or secondary follicles, respectively. About 1% of the genes were commonly mis-expressed, and EASE analysis revealed there is an over-representation of genes involved in transcription. Developmental competence of oocytes obtained from eCG-primed mice was substantially improved when compared to oocytes obtained from unprimed mice, and this correlated with decreased expression of genes implicated in basal transcription.
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Affiliation(s)
- Hua Pan
- Department of Biology, University of Pennsylvania, 415 South University Avenue, Philadelphia, PA 19104-6018, USA
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36
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Eichenlaub-Ritter U. Mouse genetic models for aneuploidy induction in germ cells. Cytogenet Genome Res 2005; 111:392-400. [PMID: 16192722 DOI: 10.1159/000086917] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Accepted: 03/04/2005] [Indexed: 12/16/2022] Open
Abstract
Rodents have been successfully used as models to identify risks of chemical exposures or age to aneuploidy induction in germ cells, which may be transmitted to the progeny. For this administration in vivo as well as exposures to in vitro maturing germ cells have been useful. Genetic models involving mice with structural chromosomal rearrangements and transgenic animals have the potential to model conditions predisposing to aneuploidy in one or both sexes, and in this way to identify potential targets for aneugens and gender-effects. The review provides an overview of mouse genetic models for aneuploidy induction in mammalian germ cells and discusses perspectives for combining genetic with experimental approaches in aneuploidy research.
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Affiliation(s)
- U Eichenlaub-Ritter
- Institute of Gentechnology/Microbiology, Faculty of Biology, University of Bielefeld, Bielefeld, Germany.
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37
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Zeng F, Schultz RM. RNA transcript profiling during zygotic gene activation in the preimplantation mouse embryo. Dev Biol 2005; 283:40-57. [PMID: 15975430 DOI: 10.1016/j.ydbio.2005.03.038] [Citation(s) in RCA: 204] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Revised: 03/28/2005] [Accepted: 03/29/2005] [Indexed: 12/30/2022]
Abstract
Zygotic gene activation is essential for development beyond the 2-cell stage in the preimplantation mouse embryo. Based on alpha-amanitin-sensitive BrUTP incorporation, transcription initiates in the 1-cell embryo and a major reprogramming of gene expression driven by newly expressed genes is prominently observed during the 2-cell stage. Superimposed on genome activation is the development of a transcriptionally repressive state that is mediated at the level of chromatin structure. The identity of the genes that are expressed during the 1- and 2-cell stages, however, is poorly described, as are those genes involved in mediating the transcriptionally repressive state. Using the Affymetrix MOE430 mouse GeneChip set, we characterized the set of alpha-amanitin-sensitive genes expressed during the 1- and 2-cell stages, and we used Expression Analysis Systematic Explorer (EASE) and Ingenuity Pathway Analysis (IPA) to identify biological and molecular processes represented by these genes, as well as interactions among them. We find that although the 1-cell embryo is transcriptionally active, we did not detect any transcripts present on the MOE430 GeneChip set to be alpha-amanitin-sensitive. Thus, what the BrUTP incorporation represents remains elusive. About 17% of genes expressed in the 2-cell embryo are alpha-amanitin-sensitive. EASE analysis reveals that genes involved in ribosome biogenesis and assembly, protein synthesis, RNA metabolism and transcription are over-represented, suggesting that genome activation during 2-cell stage may not be as global and promiscuous as previously proposed. IPA implicated Myc and Hdac1 as candidate genes involved in genome activation and the development of the transcriptionally repressive state, respectively.
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Affiliation(s)
- Fanyi Zeng
- Department of Biology, University of Pennsylvania, 415 South University Avenue, Philadelphia, PA 19104-6018, USA
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