1
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Pek JW. The idiosyncrasies of oocytes. Trends Cell Biol 2024:S0962-8924(24)00144-2. [PMID: 39142921 DOI: 10.1016/j.tcb.2024.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 07/17/2024] [Accepted: 07/18/2024] [Indexed: 08/16/2024]
Abstract
Animal oocytes face extreme challenges. They remain dormant in the body for long periods of time. To support offspring development and health, they need to store genetic material and maternal factors stably and at the same time manage cellular damage in a reliable manner. Recent studies have provided new insights on how oocytes cope with such challenges. This review discusses the many unusual or idiosyncratic nature of oocytes and how understanding oocyte biology can help us address issues of reproduction and intergenerational inheritance.
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Affiliation(s)
- Jun Wei Pek
- Temasek Life Sciences Laboratory, 1 Research Link National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive, 117543, Singapore.
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2
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Gillis A, Berry S. Global control of RNA polymerase II. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195024. [PMID: 38552781 DOI: 10.1016/j.bbagrm.2024.195024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 04/11/2024]
Abstract
RNA polymerase II (Pol II) is the multi-protein complex responsible for transcribing all protein-coding messenger RNA (mRNA). Most research on gene regulation is focused on the mechanisms controlling which genes are transcribed when, or on the mechanics of transcription. How global Pol II activity is determined receives comparatively less attention. Here, we follow the life of a Pol II molecule from 'assembly of the complex' to nuclear import, enzymatic activity, and degradation. We focus on how Pol II spends its time in the nucleus, and on the two-way relationship between Pol II abundance and activity in the context of homeostasis and global transcriptional changes.
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Affiliation(s)
- Alexander Gillis
- EMBL Australia Node in Single Molecule Science, University of New South Wales, Sydney, Australia; UNSW RNA Institute, University of New South Wales, Sydney, Australia; Department of Molecular Medicine, School of Biomedical Sciences, University of New South Wales, Sydney, Australia
| | - Scott Berry
- EMBL Australia Node in Single Molecule Science, University of New South Wales, Sydney, Australia; UNSW RNA Institute, University of New South Wales, Sydney, Australia; Department of Molecular Medicine, School of Biomedical Sciences, University of New South Wales, Sydney, Australia
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3
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An H, Wang X, Li J, Sun H, Zhu S, Ge J, Han L, Shen B, Wang Q. KAS-seq profiling captures transcription dynamics during oocyte maturation. J Ovarian Res 2024; 17:23. [PMID: 38267939 PMCID: PMC10807090 DOI: 10.1186/s13048-023-01342-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 12/31/2023] [Indexed: 01/26/2024] Open
Abstract
In fully grown oocytes, the genome is considered to be globally transcriptionally silenced. However, this conclusion is primarily derived from the results obtained through immunofluorescence staining or inferred from the highly condensed state of chromosomes, lacking more direct evidence. Here, by using a kethoxal-assisted single-stranded DNA sequencing (KAS-seq) approach, we investigated the landscape of single-strand DNA (ssDNA) throughout the genome and provided a readout of the activity and dynamics of transcription during oocyte meiotic maturation. In non-surrounded nucleolus (NSN) oocytes, we observed a robust KAS-seq signal, indicating the high transcriptional activity. In surrounded nucleolus (SN) oocytes, the presence of ssDNA still persists although the KAS-seq signal was relatively weak, suggesting the presence of transcription. Accompanying with the meiotic resumption, the transcriptional activity gradually decreased, and global repression was detected in matured oocytes. Moreover, we preformed the integrative genomics analysis to dissect the transcriptional dynamics during mouse oocyte maturation. In sum, the present study delineates the detailed transcriptional activity during mammalian oocyte maturation.
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Affiliation(s)
- Huiqing An
- State Key Laboratory of Reproductive Medicine and Offspring Health, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, 101 Longmian Rd, Nanjing, 211166, China
| | - Xiuwan Wang
- State Key Laboratory of Reproductive Medicine and Offspring Health, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, 101 Longmian Rd, Nanjing, 211166, China
| | - Jiashuo Li
- State Key Laboratory of Reproductive Medicine and Offspring Health, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, 101 Longmian Rd, Nanjing, 211166, China
| | - Hongzheng Sun
- State Key Laboratory of Reproductive Medicine and Offspring Health, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, 101 Longmian Rd, Nanjing, 211166, China
| | - Shuai Zhu
- State Key Laboratory of Reproductive Medicine and Offspring Health, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, 101 Longmian Rd, Nanjing, 211166, China
| | - Juan Ge
- State Key Laboratory of Reproductive Medicine and Offspring Health, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, 101 Longmian Rd, Nanjing, 211166, China
| | - Longsen Han
- State Key Laboratory of Reproductive Medicine and Offspring Health, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, 101 Longmian Rd, Nanjing, 211166, China
| | - Bin Shen
- State Key Laboratory of Reproductive Medicine and Offspring Health, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, 101 Longmian Rd, Nanjing, 211166, China
| | - Qiang Wang
- State Key Laboratory of Reproductive Medicine and Offspring Health, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, 101 Longmian Rd, Nanjing, 211166, China.
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China.
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4
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Ermisch AF, Wood JR. Regulation of Oocyte mRNA Metabolism: A Key Determinant of Oocyte Developmental Competence. ADVANCES IN ANATOMY, EMBRYOLOGY, AND CELL BIOLOGY 2024; 238:23-46. [PMID: 39030353 DOI: 10.1007/978-3-031-55163-5_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/21/2024]
Abstract
The regulation of mRNA transcription and translation is uncoupled during oogenesis. The reason for this uncoupling is two-fold. Chromatin is only accessible to the transcriptional machinery during the growth phase as it condenses prior to resumption of meiosis to ensure faithful segregation of chromosomes during meiotic maturation. Thus, transcription rates are high during this time period in order to produce all of the transcripts needed for meiosis, fertilization, and embryo cleavage until the newly formed embryonic genome becomes transcriptionally active. To ensure appropriate timing of key developmental milestones including chromatin condensation, resumption of meiosis, segregation of chromosomes, and polar body extrusion, the translation of protein from transcripts synthesized during oocyte growth must be temporally regulated. This is achieved by the regulation of mRNA interaction with RNA binding proteins and shortening and lengthening of the poly(A) tail. This chapter details the essential factors that regulate the dynamic changes in mRNA synthesis, storage, translation, and degradation during oocyte growth and maturation.
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Affiliation(s)
- Alison F Ermisch
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Jennifer R Wood
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, USA.
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5
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Sun X, Wang D, Li W, Gao Q, Tao J, Liu H. Comprehensive analysis of nonsurrounded nucleolus and surrounded nucleolus oocytes on chromatin accessibility using ATAC-seq. Mol Reprod Dev 2023; 90:87-97. [PMID: 36598871 DOI: 10.1002/mrd.23668] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/13/2022] [Accepted: 12/25/2022] [Indexed: 01/05/2023]
Abstract
Mouse germinal vesicle (GV) oocytes are divided into surrounded nucleolus (SN) and nonsurrounded nucleolus (NSN) oocytes based on chromatin morphology. NSN oocytes spontaneously transform into SN oocytes after accumulating enough maternal transcripts. SN oocytes show transcriptional silencing. When oocyte maturation is abnormal or takes place in vitro, NSN oocytes do not go through SN stage before proceeding to MII. Nontransitive oocytes show developmental retardation, a low fertilization rate, and arrest at the two-cell embryo stage in mice. Here, chromatin-binding ribonucleic acid polymerase II (RNAP II) activity, newly synthesized RNA, and chromatin accessibility in GV oocytes were examined. In SN oocytes, RNAP II did not bind to DNA, neo-RNA was not generated in nuclei, and the phosphorylation state of RNAP II did not affect the chromatin-binding activity. The number of accessible genes in SN oocytes was remarkably lower than that in NSN oocytes. The accessibility of different functional genes was also different between the two types of oocytes. Thus, low chromatin accessibility leads to transcriptional silencing in SN oocytes.
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Affiliation(s)
- Xiaofan Sun
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Dayu Wang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Weijian Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Qian Gao
- Laboratory Animal Center, College of Veterinary Medicine, Nanjing Agriculture University, Nanjing, China
| | - Jingli Tao
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Honglin Liu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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6
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Renaud MS, Seroussi U, Claycomb JM. Analysis of C. elegans Germline Small RNA Pathways. Methods Mol Biol 2023; 2677:37-59. [PMID: 37464234 DOI: 10.1007/978-1-0716-3259-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Sequence-specific gene regulation by small RNA (sRNA) pathways is essential for the development and function of organisms in all domains of life. These regulatory complexes, containing an Argonaute protein (AGO) guided by a bound sRNA, have the potential to regulate thousands of individual target transcripts at both the co- and post-transcriptional level. Determining the repertoire of transcripts that an AGO is capable of regulating in a particular context is essential to understanding the function of these regulatory modules. Immunoprecipitation (IP) of AGOs and subsequent RNA sequencing of their bound sRNAs allows for the inference of their target transcripts by mapping the sequences of the co-precipitated sRNAs back to their complementary target transcripts. This approach can be complemented by sequencing sRNAs from ago mutants as sRNA transcripts are degraded in the absence of their AGO binding partner. Here, we describe a framework for analyzing AGO/sRNA pathways in the germline, from using CRISPR-Cas9 to tag or mutate AGOs, through protocols for the extraction, sequencing, and analysis of sRNAs from AGO IPs and ago mutants.
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Affiliation(s)
- Mathias S Renaud
- Department of Molecular Genetics, University of Toronto, Toronto, ON, USA
| | - Uri Seroussi
- Department of Molecular Genetics, University of Toronto, Toronto, ON, USA
| | - Julie M Claycomb
- Department of Molecular Genetics, University of Toronto, Toronto, ON, USA.
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7
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Abe K, Schauer T, Torres-Padilla ME. Distinct patterns of RNA polymerase II and transcriptional elongation characterize mammalian genome activation. Cell Rep 2022; 41:111865. [PMID: 36577375 DOI: 10.1016/j.celrep.2022.111865] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 09/08/2022] [Accepted: 09/30/2022] [Indexed: 12/28/2022] Open
Abstract
How transcription is regulated as development commences is fundamental to understand how the transcriptionally silent mature gametes are reprogrammed. The embryonic genome is activated for the first time during zygotic genome activation (ZGA). How RNA polymerase II (Pol II) and productive elongation are regulated during this process remains elusive. Here, we generate genome-wide maps of Serine 5 and Serine 2-phosphorylated Pol II during and after ZGA in mouse embryos. We find that both phosphorylated Pol II forms display similar distributions across genes during ZGA, with typical elongation enrichment of Pol II emerging after ZGA. Serine 2-phosphorylated Pol II occurs at genes prior to their activation, suggesting that Serine 2 phosphorylation may prime gene expression. Functional perturbations demonstrate that CDK9 and SPT5 are major ZGA regulators and that SPT5 prevents precocious activation of some genes. Overall, our work sheds molecular insights into transcriptional regulation at the beginning of mammalian development.
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Affiliation(s)
- Kenichiro Abe
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, 81377 München, Germany
| | - Tamas Schauer
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, 81377 München, Germany; Bioinformatics Unit, Biomedical Center, Ludwig-Maximilians-University, 82152 Planegg-Martinsried, Germany
| | - Maria-Elena Torres-Padilla
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, 81377 München, Germany; Faculty of Biology, Ludwig-Maximilians Universität, München, Germany.
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8
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Jiang ZY, Fan HY. Five questions toward mRNA degradation in oocytes and preimplantation embryos: When, who, to whom, how, and why? Biol Reprod 2022; 107:62-75. [DOI: 10.1093/biolre/ioac014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/10/2022] [Accepted: 01/15/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract
RNA, the primary product of the genome, is subject to various biological events during its lifetime. During mammalian gametogenesis and early embryogenesis, germ cells and preimplantation embryos undergo marked changes in the transcriptome, including mRNA turnover. Various factors, including specialized proteins, RNAs, and organelles, function in an intricate degradation system, and the degradation selectivity is determined by effectors and their target mRNAs. RNA homeostasis regulators and surveillance factors function in the global transcriptome of oocytes and somatic cells. Other factors, including BTG4, PABPN1L, the CCR4-NOT subunits, CNOT6L and CNOT7, and TUTs, are responsible for two maternal mRNA avalanches: M- and Z-decay. In this review, we discuss recent advances in mRNA degradation mechanisms in mammalian oocytes and preimplantation embryos. We focused on the studies in mice, as a model mammalian species, and on RNA turnover effectors and the cis-elements in targeting RNAs.
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Affiliation(s)
- Zhi-Yan Jiang
- Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Heng-Yu Fan
- Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
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9
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What defines the maternal transcriptome? Biochem Soc Trans 2021; 49:2051-2062. [PMID: 34415300 PMCID: PMC8589422 DOI: 10.1042/bst20201125] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/05/2021] [Accepted: 07/19/2021] [Indexed: 01/09/2023]
Abstract
In somatic cells, RNA polymerase II (Pol II) transcription initiation starts by the binding of the general transcription factor TFIID, containing the TATA-binding protein (TBP) and 13 TBP-associated factors (TAFs), to core promoters. However, in growing oocytes active Pol II transcription is TFIID/TBP-independent, as during oocyte growth TBP is replaced by its vertebrate-specific paralog TBPL2. TBPL2 does not interact with TAFs, but stably associates with TFIIA. The maternal transcriptome is the population of mRNAs produced and stored in the cytoplasm of growing oocytes. After fertilization, maternal mRNAs are inherited by the zygote from the oocyte. As transcription becomes silent after oocyte growth, these mRNAs are the sole source for active protein translation. They will participate to complete the protein pool required for oocyte terminal differentiation, fertilization and initiation of early development, until reactivation of transcription in the embryo, called zygotic genome activation (ZGA). All these events are controlled by an important reshaping of the maternal transcriptome. This procedure combines cytoplasmic readenylation of stored transcripts, allowing their translation, and different waves of mRNA degradation by deadenylation coupled to decapping, to eliminate transcripts coding for proteins that are no longer required. The reshaping ends after ZGA with an almost total clearance of the maternal transcripts. In the past, the murine maternal transcriptome has received little attention but recent progresses have brought new insights into the regulation of maternal mRNA dynamics in the mouse. This review will address past and recent data on the mechanisms associated with maternal transcriptome dynamic in the mouse.
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10
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Xia W, Xie W. Rebooting the Epigenomes during Mammalian Early Embryogenesis. Stem Cell Reports 2020; 15:1158-1175. [PMID: 33035464 PMCID: PMC7724468 DOI: 10.1016/j.stemcr.2020.09.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 02/08/2023] Open
Abstract
Upon fertilization, terminally differentiated gametes are transformed to a totipotent zygote, which gives rise to an embryo. How parental epigenetic memories are inherited and reprogrammed to accommodate parental-to-zygotic transition remains a fundamental question in developmental biology, epigenetics, and stem cell biology. With the rapid advancement of ultra-sensitive or single-cell epigenome analysis methods, unusual principles of epigenetic reprogramming begin to be unveiled. Emerging data reveal that in many species, the parental epigenome undergoes dramatic reprogramming followed by subsequent re-establishment of the embryo epigenome, leading to epigenetic "rebooting." Here, we discuss recent progress in understanding epigenetic reprogramming and their functions during mammalian early development. We also highlight the conserved and species-specific principles underlying diverse regulation of the epigenome in early embryos during evolution.
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Affiliation(s)
- Weikun Xia
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China.
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11
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Liu B, Xu Q, Wang Q, Feng S, Lai F, Wang P, Zheng F, Xiang Y, Wu J, Nie J, Qiu C, Xia W, Li L, Yu G, Lin Z, Xu K, Xiong Z, Kong F, Liu L, Huang C, Yu Y, Na J, Xie W. The landscape of RNA Pol II binding reveals a stepwise transition during ZGA. Nature 2020; 587:139-144. [PMID: 33116310 DOI: 10.1038/s41586-020-2847-y] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 08/04/2020] [Indexed: 12/22/2022]
Abstract
Zygotic genome activation (ZGA) is the first transcription event in life1. However, it is unclear how RNA polymerase is engaged in initiating ZGA in mammals. Here, by developing small-scale Tn5-assisted chromatin cleavage with sequencing (Stacc-seq), we investigated the landscapes of RNA polymerase II (Pol II) binding in mouse embryos. We found that Pol II undergoes 'loading', 'pre-configuration', and 'production' during the transition from minor ZGA to major ZGA. After fertilization, Pol II is preferentially loaded to CG-rich promoters and accessible distal regions in one-cell embryos (loading), in part shaped by the inherited parental epigenome. Pol II then initiates relocation to future gene targets before genome activation (pre-configuration), where it later engages in full transcription elongation upon major ZGA (production). Pol II also maintains low poising at inactive promoters after major ZGA until the blastocyst stage, coinciding with the loss of promoter epigenetic silencing factors. Notably, inhibition of minor ZGA impairs the Pol II pre-configuration and embryonic development, accompanied by aberrant retention of Pol II and ectopic expression of one-cell targets upon major ZGA. Hence, stepwise transition of Pol II occurs when mammalian life begins, and minor ZGA has a key role in the pre-configuration of transcription machinery and chromatin for genome activation.
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Affiliation(s)
- Bofeng Liu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Qianhua Xu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Qiujun Wang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Su Feng
- R&D Department, Vazyme Biotech Co., Ltd, Nanjing, China
| | - Fangnong Lai
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Peizhe Wang
- Center for Stem Cell Biology and Regenerative Medicine, School of Medicine, Tsinghua University, Beijing, China
| | | | - Yunlong Xiang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Jingyi Wu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China.,Department of Pathology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Junwei Nie
- R&D Department, Vazyme Biotech Co., Ltd, Nanjing, China
| | - Cui Qiu
- R&D Department, Vazyme Biotech Co., Ltd, Nanjing, China
| | - Weikun Xia
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Lijia Li
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Guang Yu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Zili Lin
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Kai Xu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Zhuqing Xiong
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Feng Kong
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Ling Liu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Chunyi Huang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Yang Yu
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jie Na
- Center for Stem Cell Biology and Regenerative Medicine, School of Medicine, Tsinghua University, Beijing, China
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China. .,Tsinghua-Peking Center for Life Sciences, Beijing, China.
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12
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Takada Y, Iyyappan R, Susor A, Kotani T. Posttranscriptional regulation of maternal Pou5f1/Oct4 during mouse oogenesis and early embryogenesis. Histochem Cell Biol 2020; 154:609-620. [PMID: 32930837 DOI: 10.1007/s00418-020-01915-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2020] [Indexed: 12/11/2022]
Abstract
Protein syntheses at appropriate timings are important for promoting diverse biological processes and are controlled at the levels of transcription and translation. Pou5f1/Oct4 is a transcription factor that is essential for vertebrate embryonic development. However, the precise timings when the mRNA and protein of Pou5f1/Oct4 are expressed during oogenesis and early stages of embryogenesis remain unclear. We analyzed the expression patterns of mRNA and protein of Pou5f1/Oct4 in mouse oocytes and embryos by using a highly sensitive in situ hybridization method and a monoclonal antibody specific to Pou5f1/Oct4, respectively. Pou5f1/Oct4 mRNA was detected in growing oocytes from the primary follicle stage to the fully grown GV stage during oogenesis. In contrast, Pou5f1/Oct4 protein was undetectable during oogenesis, oocyte maturation and the first cleavage stage but subsequently became detectable in the nuclei of early 2-cell-stage embryos. Pou5f1/Oct4 protein at this stage was synthesized from maternal mRNAs stored in oocytes. The amount of Pou5f1/Oct4 mRNA in the polysomal fraction was small in GV-stage oocytes but was significantly increased in fertilized eggs. Taken together, our results indicate that the synthesis of Pou5f1/Oct4 protein during oogenesis and early stages of embryogenesis is controlled at the level of translation and suggest that precise control of the amount of this protein by translational regulation is important for oocyte development and early embryonic development.
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Affiliation(s)
- Yuki Takada
- Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Rajan Iyyappan
- Laboratory of Biochemistry and Molecular Biology of Germ Cells, Institute of Animal Physiology and Genetics, CAS, Rumburska 89, 277 21, Libechov, Czech Republic
| | - Andrej Susor
- Laboratory of Biochemistry and Molecular Biology of Germ Cells, Institute of Animal Physiology and Genetics, CAS, Rumburska 89, 277 21, Libechov, Czech Republic
| | - Tomoya Kotani
- Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810, Japan. .,Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan.
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13
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Lau AYT, Xie Y, Cheung MK, Cheung PCK, Kwan HS. Genome-wide mRNA and miRNA analysis in the early stages of germ tube outgrowth in Coprinopsis cinerea. Fungal Genet Biol 2020; 142:103416. [PMID: 32522620 DOI: 10.1016/j.fgb.2020.103416] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 05/28/2020] [Accepted: 06/01/2020] [Indexed: 01/28/2023]
Abstract
Coprinopsis cinerea is a model mushroom-forming basidiomycete which produces basidiospores during sexual reproduction. This fungus is widely used to study fruiting body formation and development. Molecular mechanisms controlling its growth from vegetative mycelium to multicellular mature fruiting body have been studied extensively. However, little is known about the underlying biological processes during germ tube outgrowth or the transition from basidiospores to multinucleate hyphae. To better understand sexual spore germination in fungi, here we examined the time-dependent cellular events at resting, germinating and fully germinated basidiospores of C. cinerea by genome-wide transcriptional and post-transcriptional analyses and by carbohydrate composition analysis. Our results revealed a high demand of protein degradation, and biosynthesis of various compounds at the early stage of basidiospore gemination and dynamic changes of carbohydrate metabolism throughout the germination process. Seven microRNA-like RNAs (milRNAs) were identified in the resting basidiospores of C. cinerea, six of which were basidiospore-specific. Glycogen and trehalose were shown to be the carbon sources supporting the initiation of germ tube outgrowth. One basidiospore-specific milRNA, cci-milR-37, was found to be a potential regulator of glycogen metabolic pathways related to vegetative hyphal growth. Our results demonstrated the mRNA and miRNA-mediated regulation on energy production, protein and carbohydrate metabolisms at the early developmental stages of germ tube to form totipotent hyphae. To our knowledge, this is the first study to show the roles of miRNAs in mushroom basidiospore germination and out-growth.
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Affiliation(s)
- Amy Yuet Ting Lau
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Yichun Xie
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Man Kit Cheung
- Department of Surgery, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Peter Chi Keung Cheung
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong; CUHK Shenzhen Research Institute, Shenzhen, China
| | - Hoi Shan Kwan
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong; HSK GeneTech Limited, Science Park, Shatin, New Territories, Hong Kong; Probiolife Limited, Science Park, Shatin, New Territories, Hong Kong; Mushroom-X Limited, Cheung Sha Wan Plaza, Lai Chi Kok, Kowloon, Hong Kong.
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14
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Du Z, Zheng H, Kawamura YK, Zhang K, Gassler J, Powell S, Xu Q, Lin Z, Xu K, Zhou Q, Ozonov EA, Véron N, Huang B, Li L, Yu G, Liu L, Au Yeung WK, Wang P, Chang L, Wang Q, He A, Sun Y, Na J, Sun Q, Sasaki H, Tachibana K, Peters AHFM, Xie W. Polycomb Group Proteins Regulate Chromatin Architecture in Mouse Oocytes and Early Embryos. Mol Cell 2020; 77:825-839.e7. [PMID: 31837995 DOI: 10.1016/j.molcel.2019.11.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/03/2019] [Accepted: 11/08/2019] [Indexed: 11/18/2022]
Abstract
In mammals, chromatin organization undergoes drastic reorganization during oocyte development. However, the dynamics of three-dimensional chromatin structure in this process is poorly characterized. Using low-input Hi-C (genome-wide chromatin conformation capture), we found that a unique chromatin organization gradually appears during mouse oocyte growth. Oocytes at late stages show self-interacting, cohesin-independent compartmental domains marked by H3K27me3, therefore termed Polycomb-associating domains (PADs). PADs and inter-PAD (iPAD) regions form compartment-like structures with strong inter-domain interactions among nearby PADs. PADs disassemble upon meiotic resumption from diplotene arrest but briefly reappear on the maternal genome after fertilization. Upon maternal depletion of Eed, PADs are largely intact in oocytes, but their reestablishment after fertilization is compromised. By contrast, depletion of Polycomb repressive complex 1 (PRC1) proteins attenuates PADs in oocytes, which is associated with substantial gene de-repression in PADs. These data reveal a critical role of Polycomb in regulating chromatin architecture during mammalian oocyte growth and early development.
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Affiliation(s)
- Zhenhai Du
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hui Zheng
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yumiko K Kawamura
- Friedrich Miescher Institute for Biomedical Research, Basel 4058, Switzerland
| | - Ke Zhang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Johanna Gassler
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Sean Powell
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Qianhua Xu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zili Lin
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Kai Xu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qian Zhou
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Evgeniy A Ozonov
- Friedrich Miescher Institute for Biomedical Research, Basel 4058, Switzerland
| | - Nathalie Véron
- Friedrich Miescher Institute for Biomedical Research, Basel 4058, Switzerland
| | - Bo Huang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lijia Li
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guang Yu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ling Liu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wan Kin Au Yeung
- Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Peizhe Wang
- Center for Stem Cell Biology and Regenerative Medicine, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Lei Chang
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Qiujun Wang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Aibin He
- Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing 100871, China
| | - Yujie Sun
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Jie Na
- Center for Stem Cell Biology and Regenerative Medicine, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Qingyuan Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hiroyuki Sasaki
- Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Kikuë Tachibana
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna Biocenter (VBC), 1030 Vienna, Austria; Department of Totipotency, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Antoine H F M Peters
- Friedrich Miescher Institute for Biomedical Research, Basel 4058, Switzerland; Faculty of Sciences, University of Basel, Basel 4056, Switzerland.
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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15
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Greenblatt EJ, Obniski R, Mical C, Spradling AC. Prolonged ovarian storage of mature Drosophila oocytes dramatically increases meiotic spindle instability. eLife 2019; 8:49455. [PMID: 31755866 PMCID: PMC6905857 DOI: 10.7554/elife.49455] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 11/17/2019] [Indexed: 12/21/2022] Open
Abstract
Human oocytes frequently generate aneuploid embryos that subsequently miscarry. In contrast, Drosophila oocytes from outbred laboratory stocks develop fully regardless of maternal age. Since mature Drosophila oocytes are not extensively stored in the ovary under laboratory conditions like they are in the wild, we developed a system to investigate how storage affects oocyte quality. The developmental capacity of stored mature Drosophila oocytes decays in a precise manner over 14 days at 25°C. These oocytes are transcriptionally inactive and persist using ongoing translation of stored mRNAs. Ribosome profiling revealed a progressive 2.3-fold decline in average translational efficiency during storage that correlates with oocyte functional decay. Although normal bipolar meiotic spindles predominate during the first week, oocytes stored for longer periods increasingly show tripolar, monopolar and other spindle defects, and give rise to embryos that fail to develop due to aneuploidy. Thus, meiotic chromosome segregation in mature Drosophila oocytes is uniquely sensitive to prolonged storage. Our work suggests the chromosome instability of human embryos could be mitigated by reducing the period of time mature human oocytes are stored in the ovary prior to ovulation.
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Affiliation(s)
- Ethan J Greenblatt
- Department of Embryology, Howard Hughes Medical Institute Research Laboratories, Carnegie Institution for Science, Baltimore, United States
| | - Rebecca Obniski
- Department of Embryology, Howard Hughes Medical Institute Research Laboratories, Carnegie Institution for Science, Baltimore, United States
| | - Claire Mical
- Department of Embryology, Howard Hughes Medical Institute Research Laboratories, Carnegie Institution for Science, Baltimore, United States
| | - Allan C Spradling
- Department of Embryology, Howard Hughes Medical Institute Research Laboratories, Carnegie Institution for Science, Baltimore, United States
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16
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Fulka H, Ogura A, Loi P, Fulka Jr J. Dissecting the role of the germinal vesicle nuclear envelope and soluble content in the process of somatic cell remodelling and reprogramming. J Reprod Dev 2019; 65:433-441. [PMID: 31423000 PMCID: PMC6815741 DOI: 10.1262/jrd.2019-017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Differentiated nuclei can be reprogrammed/remodelled to totipotency after their transfer to enucleated metaphase II (MII) oocytes. The process of reprogramming/remodelling is, however, only
partially characterized. It has been shown that the oocyte nucleus (germinal vesicle – GV) components are essential for a successful remodelling of the transferred nucleus by providing the
materials for pseudo-nucleus formation. However, the nucleus is a complex structure and exactly what nuclear components are required for a successful nucleus remodelling and reprogramming is
unknown. Till date, the only nuclear sub-structure experimentally demonstrated to be essential is the oocyte nucleolus (nucleolus-like body, NLB). In this study, we investigated what other
GV components might be necessary for the formation of normal-sized pseudo-pronuclei (PNs). Our results showed that the removal of the GV nuclear envelope with attached chromatin and
chromatin-bound factors does not substantially influence the size of the remodelled nuclei in reconstructed cells and that their nuclear envelopes seem to have normal parameters. Rather than
the insoluble nuclear lamina, the GV content, which is dissolved in the cytoplasm with the onset of oocyte maturation, influences the characteristics and size of transferred nuclei.
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Affiliation(s)
- Helena Fulka
- Institute of Molecular Genetics of the ASCR, 142 20 Prague, Czech Republic.,Institute of Experimental Medicine, 142 20 Prague, Czech Republic
| | - Atsuo Ogura
- RIKEN BioResource Center, Ibaraki 305-0074, Japan
| | - Pasqualino Loi
- Faculty of Veterinary Medicine, University of Teramo, Teramo 64100, Italy
| | - Josef Fulka Jr
- Institute of Animal Science, 140 00 Prague, Czech Republic
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17
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Samarin AM, Samarin AM, Østbye TKK, Ruyter B, Sampels S, Burkina V, Blecha M, Policar T. The possible involvement of oxidative stress in the oocyte ageing process in goldfish Carassius auratus (Linnaeus, 1758). Sci Rep 2019; 9:10469. [PMID: 31320670 PMCID: PMC6639355 DOI: 10.1038/s41598-019-46895-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 06/28/2019] [Indexed: 11/09/2022] Open
Abstract
Decreasing egg quality following oocyte ageing is a major restricting factor for the breeding programs. The mechanisms behind this process has not yet been clarified. To examine the possible involvement of oxidative stress in the oocyte ageing process, the relative mRNA abundance of specific transcripts were determined in oocytes collected from 6 females and incubated in vitro for 18 hours post stripping at 20 °C in goldfish Carassius auratus. During the 18 hour-post-stripping ageing of the oocytes, relative mRNA levels of candidate transcripts involved in oxidative injury, mitochondrial function and stress response, cell cycles, apoptosis, reproduction and germ line speciation and developmental competence were measured by real-time PCR. None of the relative mRNA abundance of the examined genes were significantly altered through oocyte ageing. In addition, the amount of thiobarbituric acid reactive substances (TBARS), an indicator of lipid peroxidation, did not change over time following stripping. The activity of the antioxidant enzymes also remained constant during oocyte ageing. The results of the current study indicated that oxidative stress unlikely plays a role as an initiator or promotor in the progress of oocyte ageing in goldfish.
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Affiliation(s)
- Azadeh Mohagheghi Samarin
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Azin Mohagheghi Samarin
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Zátiší 728/II, 389 25, Vodňany, Czech Republic.
| | | | - Bente Ruyter
- Nofima (Norwegian Institute of Food, Fisheries and Aquaculture Research), P.O. Box 210, NO-1431, Ås, Norway
| | - Sabine Sampels
- Swedish University of Agricultural Sciences, Department of Molecular Sciences, PO Box 7015, 75007, Uppsala, Sweden
| | - Viktoriia Burkina
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Miroslav Blecha
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Tomas Policar
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Zátiší 728/II, 389 25, Vodňany, Czech Republic
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18
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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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19
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Mihalas BP, Camlin NJ, Xavier MJ, Peters AE, Holt JE, Sutherland JM, McLaughlin EA, Eamens AL, Nixon B. The small non-coding RNA profile of mouse oocytes is modified during aging. Aging (Albany NY) 2019; 11:2968-2997. [PMID: 31128574 PMCID: PMC6555462 DOI: 10.18632/aging.101947] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/29/2019] [Indexed: 01/31/2023]
Abstract
Oocytes are reliant on messenger RNA (mRNA) stores to support their survival and integrity during a protracted period of transcriptional dormancy as they await ovulation. Oocytes are, however, known to experience an age-associated alteration in mRNA transcript abundance, a phenomenon that contributes to reduced developmental potential. Here we have investigated whether the expression profile of small non-protein-coding RNAs (sRNAs) is similarly altered in aged mouse oocytes. The application of high throughput sequencing revealed substantial changes to the global sRNA profile of germinal vesicle stage oocytes from young (4-6 weeks) and aged mice (14-16 months). Among these, 160 endogenous small-interfering RNAs (endo-siRNAs) and 10 microRNAs (miRNAs) were determined to differentially accumulate within young and aged oocytes. Further, we revealed decreased expression of two members of the kinesin protein family, Kifc1 and Kifc5b, in aged oocytes; family members selectively targeted for expression regulation by endo-siRNAs of elevated abundance. The implications of reduced Kifc1 and Kifc5b expression were explored using complementary siRNA-mediated knockdown and pharmacological inhibition strategies, both of which led to increased rates of aneuploidy in otherwise healthy young oocytes. Collectively, our data raise the prospect that altered sRNA abundance, specifically endo-siRNA abundance, could influence the quality of the aged oocyte.
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Affiliation(s)
- Bettina P Mihalas
- Priority Research Centre for Reproductive Science, Schools of Environmental and Life Sciences and Biomedical Science and Pharmacy, the University of Newcastle, Callaghan, New South Wales 2308, Australia
- Pregnancy and Reproduction Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales 2305, Australia
| | - Nicole J Camlin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21218, United States
| | - Miguel J Xavier
- Priority Research Centre for Reproductive Science, Schools of Environmental and Life Sciences and Biomedical Science and Pharmacy, the University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Alexandra E Peters
- Priority Research Centre for Reproductive Science, Schools of Environmental and Life Sciences and Biomedical Science and Pharmacy, the University of Newcastle, Callaghan, New South Wales 2308, Australia
- Pregnancy and Reproduction Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales 2305, Australia
| | - Janet E Holt
- Priority Research Centre for Reproductive Science, Schools of Environmental and Life Sciences and Biomedical Science and Pharmacy, the University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Jessie M Sutherland
- Priority Research Centre for Reproductive Science, Schools of Environmental and Life Sciences and Biomedical Science and Pharmacy, the University of Newcastle, Callaghan, New South Wales 2308, Australia
- Pregnancy and Reproduction Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales 2305, Australia
| | - Eileen A McLaughlin
- Priority Research Centre for Reproductive Science, Schools of Environmental and Life Sciences and Biomedical Science and Pharmacy, the University of Newcastle, Callaghan, New South Wales 2308, Australia
- Pregnancy and Reproduction Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales 2305, Australia
- School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand
- School of Science, the University of Canberra, Bruce, Australian Capital Territory 2617, Australia
| | - Andrew L Eamens
- School of Environmental and Life Sciences, the University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Brett Nixon
- Priority Research Centre for Reproductive Science, Schools of Environmental and Life Sciences and Biomedical Science and Pharmacy, the University of Newcastle, Callaghan, New South Wales 2308, Australia
- Pregnancy and Reproduction Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales 2305, Australia
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20
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Berg DK, Pfeffer PL. MicroRNA expression in bovine preimplantation embryos. Reprod Fertil Dev 2018; 30:546-554. [PMID: 28847362 DOI: 10.1071/rd17101] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 08/02/2017] [Indexed: 01/05/2023] Open
Abstract
We profiled 98 mature microRNAs (miRNAs) using a stem-loop reverse transcription polymerase chain reaction assay array based on human miRNAs. We demonstrated that one, but not two, base-pair changes in the miRNA recognition sequence at the 3' end only marginally affected copy number estimates. Absolute levels of miRNAs were measured in matured cattle oocytes, eight-cell embryos and normal and parthenogenetic blastocysts and Day-14 trophoblast. Most miRNA concentrations were below the expected functional threshold required for effective repression of moderately to highly abundant target RNA. In oocytes and peri-embryonic genome activation embryos, miRNA 320, a member of the Dgcr8/Drosha-independent class of miRNAs, was expressed at greater than 1000 copies per embryo. miRNAs were more abundant at the eight-cell than the oocyte stage. miRNA concentrations per cell increased from the eight-cell to the blastocyst stage. Both the number of miRNA species and their expression levels were reduced in trophoblast tissue at Day 14. The parthenogenetic samples were more related in their miRNA expression profiles to each other than to their wild-type (in vitro-produced cultured) counterparts. miRNAs 299 and 323, which have been shown to be maternally expressed in other species, were also more than 4-fold overexpressed in the cattle parthenogenetic samples.
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Affiliation(s)
- Debra K Berg
- AgResearch Ltd, Ruakura Agricultural Centre, 10 Bisley Road, Hamilton 3214, New Zealand
| | - Peter L Pfeffer
- AgResearch Ltd, Ruakura Agricultural Centre, 10 Bisley Road, Hamilton 3214, New Zealand
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21
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Abe KI, Funaya S, Tsukioka D, Kawamura M, Suzuki Y, Suzuki MG, Schultz RM, Aoki F. Minor zygotic gene activation is essential for mouse preimplantation development. Proc Natl Acad Sci U S A 2018; 115:E6780-E6788. [PMID: 29967139 PMCID: PMC6055165 DOI: 10.1073/pnas.1804309115] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In mice, transcription initiates at the mid-one-cell stage and transcriptional activity dramatically increases during the two-cell stage, a process called zygotic gene activation (ZGA). Associated with ZGA is a marked change in the pattern of gene expression that occurs after the second round of DNA replication. To distinguish ZGA before and after the second-round DNA replication, the former and latter are called minor and major ZGA, respectively. Although major ZGA are required for development beyond the two-cell stage, the function of minor ZGA is not well understood. Transiently inhibiting minor ZGA with 5, 6-dichloro-1-β-d-ribofuranosyl-benzimidazole (DRB) resulted in the majority of embryos arresting at the two-cell stage and retention of the H3K4me3 mark that normally decreases. After release from DRB, at which time major ZGA normally occurred, transcription initiated with characteristics of minor ZGA but not major ZGA, although degradation of maternal mRNA normally occurred. Thus, ZGA occurs sequentially starting with minor ZGA that is critical for the maternal-to-zygotic transition.
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Affiliation(s)
- Ken-Ichiro Abe
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 277-8562 Kashiwa, Japan
| | - Satoshi Funaya
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 277-8562 Kashiwa, Japan
| | - Dai Tsukioka
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 277-8562 Kashiwa, Japan
| | - Machika Kawamura
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 277-8562 Kashiwa, Japan
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, 277-0882 Kashiwa, Japan
| | - Masataka G Suzuki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 277-8562 Kashiwa, Japan
| | - Richard M Schultz
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104;
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616
| | - Fugaku Aoki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 277-8562 Kashiwa, Japan;
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22
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Using Single Molecule mRNA Fluorescent in Situ Hybridization (RNA-FISH) to Quantify mRNAs in Individual Murine Oocytes and Embryos. Sci Rep 2018; 8:7930. [PMID: 29785002 PMCID: PMC5962540 DOI: 10.1038/s41598-018-26345-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 05/04/2018] [Indexed: 11/23/2022] Open
Abstract
Changes in abundance of mRNAs during oocyte growth and maturation and during pre-implantation embryo development have been documented using quantitative real-time RT-PCR (qPCR), microarray analyses, and whole genome sequencing. However, these techniques require amplification of mRNAs, normalization using housekeeping genes, can be biased for abundant transcripts, and/or require large numbers of oocytes and embryos which can be difficult to acquire from mammalian species. We optimized a single molecule RNA fluorescence in situ hybridization (RNA-FISH) protocol, which amplifies fluorescence signal to detect candidate transcripts, for use with individual oocytes and embryos. Quantification using the software Localize showed patterns of Gdf9 and Pou5f1 mRNA expression in oocytes and embryos that were consistent with previously published data. Interestingly, low levels of Nanog mRNA were also accurately and reproducibly measured in oocytes and one- and two-cell embryos suggesting that RNA-FISH could be used to detect and quantify low abundance transcripts. Unlike other techniques, RNA-FISH is also able to detect changes in the localization patterns of mRNAs which may be used to monitor post-transcriptional regulation of a transcript. Thus, RNA-FISH represents an important technique to investigate potential mechanisms associated with the synthesis and stability of candidate mRNAs in mammalian oocytes and embryos.
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23
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Freimer JW, Krishnakumar R, Cook MS, Blelloch R. Expression of Alternative Ago2 Isoform Associated with Loss of microRNA-Driven Translational Repression in Mouse Oocytes. Curr Biol 2018; 28:296-302.e3. [PMID: 29307557 DOI: 10.1016/j.cub.2017.11.067] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 08/14/2017] [Accepted: 11/29/2017] [Indexed: 12/21/2022]
Abstract
Mouse oocyte maturation, fertilization, and reprogramming occur in the absence of transcription, and thus, changes in mRNA levels and translation rate are regulated through post-transcriptional mechanisms [1]. Surprisingly, microRNA function, which is a major form of post-transcriptional regulation, is absent during this critical period of mammalian development [2, 3]. Here, we investigated the mechanisms underlying the global suppression of microRNA activity. In both mouse and frogs, microRNA function was active in growing oocytes but then absent during oocyte maturation. RNA sequencing (RNA-seq) of mouse oocytes uncovered that the microRNA effector protein AGO2 is predominantly expressed as an alternative isoform that encodes a truncated protein lacking all of the known essential domains. Full-length Ago2 as well as the related Argonautes (Ago1, Ago3, and Ago4) were lowly expressed in maturing mouse oocytes. Reintroduction of full-length AGO2 together with an exogenous microRNA in either mouse or frog oocytes restored translational repression of a target reporter. However, levels of endogenous transcripts remained unchanged. Consistent with a lack of microRNA activity, analysis of transcripts with alternative polyadenylation sites showed increased stability of transcripts with a longer 3' UTR during oocyte maturation. Redundant mechanisms protecting endogenous transcripts and the conserved loss of microRNA activity suggest a strong selection for suppressing microRNA function in vertebrate oocytes.
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Affiliation(s)
- Jacob W Freimer
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA; Department of Urology, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA
| | - Raga Krishnakumar
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA; Department of Urology, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA
| | - Matthew S Cook
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA; Department of Urology, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA
| | - Robert Blelloch
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA; Department of Urology, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA.
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Xie F, Anderson CL, Timme KR, Kurz SG, Fernando SC, Wood JR. Obesity-Dependent Increases in Oocyte mRNAs Are Associated With Increases in Proinflammatory Signaling and Gut Microbial Abundance of Lachnospiraceae in Female Mice. Endocrinology 2016; 157:1630-43. [PMID: 26881311 PMCID: PMC4816731 DOI: 10.1210/en.2015-1851] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
RNAs stored in the metaphase II-arrested oocyte play important roles in successful embryonic development. Their abundance is defined by transcriptional activity during oocyte growth and selective degradation of transcripts during LH-induced oocyte maturation. Our previous studies demonstrated that mRNA abundance is increased in mature ovulated oocytes collected from obese humans and mice and therefore may contribute to reduced oocyte developmental competence associated with metabolic dysfunction. In the current study mouse models of diet-induced obesity were used to determine whether obesity-dependent increases in proinflammatory signaling regulate ovarian abundance of oocyte-specific mRNAs. The abundance of oocyte-specific Bnc1, Dppa3, and Pou5f1 mRNAs as well as markers of proinflammatory signaling were significantly increased in ovaries of obese compared with lean mice which were depleted of fully grown preovulatory follicles. Chromatin-immunoprecipitation analyses also demonstrated increased association of phosphorylated signal transducer and activator of transcription 3 with the Pou5f1 promoter in ovaries of obese mice suggesting that proinflammatory signaling regulates transcription of this gene in the oocyte. The cecum microbial content of lean and obese female mice was subsequently examined to identify potential relationships between microbial composition and proinflammatory signaling in the ovary. Multivariate Association with Linear Models identified significant positive correlations between cecum abundance of the bacterial family Lachnospiraceae and ovarian abundance of Tnfa as well as Dppa3, Bnc1, and Pou5f1 mRNAs. Together, these data suggest that diet-induced changes in gut microbial composition may be contributing to ovarian inflammation which in turn alters ovarian gene expression and ultimately contributes to obesity-dependent reduction in oocyte quality and development of infertility in obese patients.
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Affiliation(s)
- Fang Xie
- Department of Animal Science (F.X., K.R.T., S.G.K., S.C.F., J.R.W.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0908; School of Biological Sciences (C.L.A., S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0118; and Food Science and Technology Department (S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0919
| | - Christopher L Anderson
- Department of Animal Science (F.X., K.R.T., S.G.K., S.C.F., J.R.W.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0908; School of Biological Sciences (C.L.A., S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0118; and Food Science and Technology Department (S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0919
| | - Kelsey R Timme
- Department of Animal Science (F.X., K.R.T., S.G.K., S.C.F., J.R.W.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0908; School of Biological Sciences (C.L.A., S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0118; and Food Science and Technology Department (S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0919
| | - Scott G Kurz
- Department of Animal Science (F.X., K.R.T., S.G.K., S.C.F., J.R.W.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0908; School of Biological Sciences (C.L.A., S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0118; and Food Science and Technology Department (S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0919
| | - Samodha C Fernando
- Department of Animal Science (F.X., K.R.T., S.G.K., S.C.F., J.R.W.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0908; School of Biological Sciences (C.L.A., S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0118; and Food Science and Technology Department (S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0919
| | - Jennifer R Wood
- Department of Animal Science (F.X., K.R.T., S.G.K., S.C.F., J.R.W.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0908; School of Biological Sciences (C.L.A., S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0118; and Food Science and Technology Department (S.C.F.), University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0919
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P-TEFb Kinase Activity Is Essential for Global Transcription, Resumption of Meiosis and Embryonic Genome Activation in Pig. PLoS One 2016; 11:e0152254. [PMID: 27011207 PMCID: PMC4807088 DOI: 10.1371/journal.pone.0152254] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/13/2016] [Indexed: 11/20/2022] Open
Abstract
Positive transcription elongation factor b (P-TEFb) is a RNA polymerase II carboxyl-terminal domain (Pol II CTD) kinase that phosphorylates Ser2 of the CTD and promotes the elongation phase of transcription. Despite the fact that P-TEFb has role in many cellular processes, the role of this kinase complex remains to be understood in mammalian early developmental events. In this study, using immunocytochemical analyses, we found that the P-TEFb components, CDK9, Cyclin T1 and Cyclin T2 were localized to nuclear speckles, as well as in nucleolar-like bodies in pig germinal vesicle oocytes. Using nascent RNA labeling and small molecule inhibitors, we showed that inhibition of CDK9 activity abolished the transcription of GV oocytes globally. Moreover, using fluorescence in situ hybridization, in absence of CDK9 kinase activity the production of ribosomal RNAs was impaired. We also presented the evidences indicating that P-TEFb kinase activity is essential for resumption of oocyte meiosis and embryo development. Treatment with CDK9 inhibitors resulted in germinal vesicle arrest in maturing oocytes in vitro. Inhibition of CDK9 kinase activity did not interfere with in vitro fertilization and pronuclear formation. However, when in vitro produced zygotes were treated with CDK9 inhibitors, their development beyond the 4-cell stage was impaired. In these embryos, inhibition of CDK9 abrogated global transcriptional activity and rRNA production. Collectively, our data suggested that P-TEFb kinase activity is crucial for oocyte maturation, embryo development and regulation of RNA transcription in pig.
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El-Hayek S, Clarke HJ. Control of Oocyte Growth and Development by Intercellular Communication Within the Follicular Niche. Results Probl Cell Differ 2016; 58:191-224. [PMID: 27300180 DOI: 10.1007/978-3-319-31973-5_8] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In the mammalian ovary, each oocyte grows and develops within its own structural and developmental niche-the follicle. Together with the female germ cell in the follicle are somatic granulosa cells, specialized companion cells that surround the oocyte and provide support to it, and an outer layer of thecal cells that serve crucial roles including steroid synthesis. These follicular compartments function as a single physiological unit whose purpose is to produce a healthy egg, which upon ovulation can be fertilized and give rise to a healthy embryo, thus enabling the female germ cell to fulfill its reproductive potential. Beginning from the initial stage of follicle formation and until terminal differentiation at ovulation, oocyte and follicle growth depend absolutely on cooperation between the different cellular compartments. This cooperation synchronizes the initiation of oocyte growth with follicle activation. During growth, it enables metabolic support for the follicle-enclosed oocyte and allows the follicle to fulfill its steroidogenic potential. Near the end of the growth period, intra-follicular interactions prevent the precocious meiotic resumption of the oocyte and ensure its nuclear differentiation. Finally, cooperation enables the events of ovulation, including meiotic maturation of the oocyte and expansion of the cumulus granulosa cells. In this chapter, we discuss the cellular interactions that enable the growing follicle to produce a healthy oocyte, focusing on the communication between the germ cell and the surrounding granulosa cells.
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Affiliation(s)
- Stephany El-Hayek
- Department of Obstetrics and Gynecology, McGill University, Montreal, QC, Canada
- Department of Biology, McGill University, Montreal, QC, Canada
- Research Institute of the McGill University Health Centre, 1001 Decarie Blvd, Block E-M0.2218, Montreal, QC, Canada, H4A 3J1
| | - Hugh J Clarke
- Department of Obstetrics and Gynecology, McGill University, Montreal, QC, Canada.
- Department of Biology, McGill University, Montreal, QC, Canada.
- Research Institute of the McGill University Health Centre, 1001 Decarie Blvd, Block E-M0.2218, Montreal, QC, Canada, H4A 3J1.
- Department of Experimental Medicine, McGill University, Montreal, QC, Canada.
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27
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Wei H, Wang Q, DU J, Li X, Zhang N, Cao Y, Ma W. Unique subcellular distribution of RPB1 with a phosphorylated C-terminal domain (CTD) in mouse oocytes during meiotic division and its relationship with chromosome separation. J Reprod Dev 2015; 61:541-8. [PMID: 26346254 PMCID: PMC4685220 DOI: 10.1262/jrd.2015-051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Polymerase (RNA) II (DNA directed) polypeptide A (RPB1) is the largest subunit of RNA polymerase II
(RNAPII), and phosphorylation of its C-terminal domain (CTD) is required for transcription initiation,
elongation and RNA processing. Little is known about the CTD phosphorylation pattern and potential function
during cell division when transcription is silenced. In this study, we assessed the protein expression and
subcellular distribution of RPB1 during mouse oocyte meiotic division. Western blot analysis revealed that the
RPB1 CTD was highly phosphorylated on Ser2 (pRPB1Ser2), Ser5 (pRPB1Ser5) and Ser7
(pRPB1Ser7). High and stable expression of pRPB1Ser2 and pRPB1Ser5 was
detected from germinal vesicle (GV) to Metaphase II (MII) stage. In contrast, pRPB1Ser7 only
emerged after germinal vesicle breakdown (GVBD) and gradually increased to its peak level at metaphase I (MI)
and MII. Immunofluorescence demonstrated that pRPB1Ser2, pRPB1Ser5 and
pRPB1Ser7 were pronouncedly aggregated within the nucleus of GV oocytes with a non-surrounded
nucleolus (NSN) but very faintly labeled in oocytes with a surrounded nucleolus (SN). After meiotic
resumption, pRPB1Ser2 was again detected at spindle poles and co-localized with key microtubule
organizing center (MTOC) components, pericentrin and γ-tubulin. pRPB1Ser5 and pRPB1Ser7
were assembled as filamentous aggregates and co-localized with microtubules throughout the spindle structure,
responding to spindle-disturbing drugs, nocodazole or taxol, in pattern strongly similar to microtubules.
pRPB1Ser2 and pRPB1Ser5 were constantly localized on chromosomes, with a relatively
high concentration in centromere areas. Taken together, our data suggest that the CTD is highly phosphorylated
and may be required for accurate chromosome segregation in mouse oocytes during meiosis.
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Affiliation(s)
- HaoJie Wei
- Department of Histology and Embryology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
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28
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Svoboda P, Franke V, Schultz RM. Sculpting the Transcriptome During the Oocyte-to-Embryo Transition in Mouse. Curr Top Dev Biol 2015; 113:305-49. [PMID: 26358877 DOI: 10.1016/bs.ctdb.2015.06.004] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In mouse, the oocyte-to-embryo transition entails converting a highly differentiated oocyte to totipotent blastomeres. This transition is driven by degradation of maternal mRNAs, which results in loss of oocyte identity, and reprogramming of gene expression during the course of zygotic gene activation, which occurs primarily during the two-cell stage and confers blastomere totipotency. Full-grown oocytes are transcriptionally quiescent and mRNAs are remarkably stable in oocytes due to the RNA-binding protein MSY2, which stabilizes mRNAs, and low activity of the 5' and 3' RNA degradation machinery. Oocyte maturation initiates a transition from mRNA stability to instability due to phosphorylation of MSY2, which makes mRNAs more susceptible to the RNA degradation machinery, and recruitment of dormant maternal mRNAs that encode for critical components of the 5' and 3' RNA degradation machinery. Small RNAs (miRNA, siRNA, and piRNA) play little, if any, role in mRNA degradation that occurs during maturation. Many mRNAs are totally degraded but a substantial fraction is only partially degraded, their degradation completed by the end of the two-cell stage. Genome activation initiates during the one-cell stage, is promiscuous, low level, and genome wide (and includes both inter- and intragenic regions) and produces transcripts that are inefficiently spliced and polyadenylated. The major wave of genome activation in two-cell embryos involves expression of thousands of new genes. This unique pattern of gene expression is the product of maternal mRNAs recruited during maturation that encode for transcription factors and chromatin remodelers, as well as dramatic changes in chromatin structure due to incorporation of histone variants and modified histones.
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Affiliation(s)
- Petr Svoboda
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
| | - Vedran Franke
- Bioinformatics Group, Division of Biology, Faculty of Science, Zagreb University, Zagreb, Croatia
| | - Richard M Schultz
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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29
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Abe KI, Yamamoto R, Franke V, Cao M, Suzuki Y, Suzuki MG, Vlahovicek K, Svoboda P, Schultz RM, Aoki F. The first murine zygotic transcription is promiscuous and uncoupled from splicing and 3' processing. EMBO J 2015; 34:1523-37. [PMID: 25896510 DOI: 10.15252/embj.201490648] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 03/19/2015] [Indexed: 12/18/2022] Open
Abstract
Initiation of zygotic transcription in mammals is poorly understood. In mice, zygotic transcription is first detected shortly after pronucleus formation in 1-cell embryos, but the identity of the transcribed loci and mechanisms regulating their expression are not known. Using total RNA-Seq, we have found that transcription in 1-cell embryos is highly promiscuous, such that intergenic regions are extensively expressed and thousands of genes are transcribed at comparably low levels. Striking is that transcription can occur in the absence of defined core-promoter elements. Furthermore, accumulation of translatable zygotic mRNAs is minimal in 1-cell embryos because of inefficient splicing and 3' processing of nascent transcripts. These findings provide novel insights into regulation of gene expression in 1-cell mouse embryos that may confer a protective mechanism against precocious gene expression that is the product of a relaxed chromatin structure present in 1-cell embryos. The results also suggest that the first zygotic transcription itself is an active component of chromatin remodeling in 1-cell embryos.
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Affiliation(s)
- Ken-Ichiro Abe
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Ryoma Yamamoto
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Vedran Franke
- Bioinformatics Group, Division of Biology, Faculty of Science, Zagreb University, Zagreb, Croatia
| | - Minjun Cao
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Yutaka Suzuki
- Department of Medical Genome Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan The University of Tokyo, Tokyo, Japan
| | - Masataka G Suzuki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Kristian Vlahovicek
- Bioinformatics Group, Division of Biology, Faculty of Science, Zagreb University, Zagreb, Croatia Department of Informatics, University of Oslo, Oslo, Norway
| | - Petr Svoboda
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Richard M Schultz
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Fugaku Aoki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
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30
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Pattabiraman S, Baumann C, Guisado D, Eppig JJ, Schimenti JC, De La Fuente R. Mouse BRWD1 is critical for spermatid postmeiotic transcription and female meiotic chromosome stability. ACTA ACUST UNITED AC 2014; 208:53-69. [PMID: 25547156 PMCID: PMC4284233 DOI: 10.1083/jcb.201404109] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Exhibiting sexually dimorphic roles in mice, BRWD1 is essential for proper meiotic chromosome condensation and telomere structure during oogenesis and for haploid-specific gene transcription during postmeiotic sperm differentiation. Postmeiotic gene expression is essential for development and maturation of sperm and eggs. We report that the dual bromodomain-containing protein BRWD1, which is essential for both male and female fertility, promotes haploid spermatid–specific transcription but has distinct roles in oocyte meiotic progression. Brwd1 deficiency caused down-regulation of ∼300 mostly spermatid-specific transcripts in testis, including nearly complete elimination of those encoding the protamines and transition proteins, but was not associated with global epigenetic changes in chromatin, which suggests that BRWD1 acts selectively. In females, Brwd1 ablation caused severe chromosome condensation and structural defects associated with abnormal telomere structure but only minor changes in gene expression at the germinal vesicle stage, including more than twofold overexpression of the histone methyltransferase MLL5 and LINE-1 elements transposons. Thus, loss of BRWD1 function interferes with the completion of oogenesis and spermatogenesis through sexually dimorphic mechanisms: it is essential in females for epigenetic control of meiotic chromosome stability and in males for haploid gene transcription during postmeiotic sperm differentiation.
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Affiliation(s)
- Shrivatsav Pattabiraman
- Department of Biomedical Sciences and Center for Vertebrate Genomics, Cornell University, College of Veterinary Medicine, Ithaca, NY 14853 Department of Biomedical Sciences and Center for Vertebrate Genomics, Cornell University, College of Veterinary Medicine, Ithaca, NY 14853
| | - Claudia Baumann
- Department of Physiology and Pharmacology, University of Georgia College of Veterinary Medicine, Athens, GA 30602
| | - Daniela Guisado
- Department of Biomedical Sciences and Center for Vertebrate Genomics, Cornell University, College of Veterinary Medicine, Ithaca, NY 14853 Department of Biomedical Sciences and Center for Vertebrate Genomics, Cornell University, College of Veterinary Medicine, Ithaca, NY 14853
| | | | - John C Schimenti
- Department of Biomedical Sciences and Center for Vertebrate Genomics, Cornell University, College of Veterinary Medicine, Ithaca, NY 14853 Department of Biomedical Sciences and Center for Vertebrate Genomics, Cornell University, College of Veterinary Medicine, Ithaca, NY 14853
| | - Rabindranath De La Fuente
- Department of Physiology and Pharmacology, University of Georgia College of Veterinary Medicine, Athens, GA 30602
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Abstract
It has become a current social trend for women to delay childbearing. However, the quality of oocytes from older females is compromised and the pregnancy rate of older women is lower. With the increased rate of delayed childbearing, it is becoming more and more crucial to understand the mechanisms underlying the compromised quality of oocytes from older women, including mitochondrial dysfunctions, aneuploidy and epigenetic changes. Establishing proper epigenetic modifications during oogenesis and early embryo development is an important aspect in reproduction. The reprogramming process may be influenced by external and internal factors that result in improper epigenetic changes in germ cells. Furthermore, germ cell epigenetic changes might be inherited by the next generations. In this review, we briefly summarise the effects of ageing on oocyte quality. We focus on discussing the relationship between ageing and epigenetic modifications, highlighting the epigenetic changes in oocytes from advanced-age females and in post-ovulatory aged oocytes as well as the possible underlying mechanisms.
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Affiliation(s)
- Zhao-Jia Ge
- Reproductive Medicine CenterHenan Provincial People's Hospital, #7 Weiwu Road, Jinshui District, Zhengzhou, Henan Province 450003, People's Republic of ChinaState Key Laboratory of Reproductive BiologyInstitute of Zoology, Chinese Academy of Sciences, #1 Beichen West Road, Chaoyang District, Beijing 100101, People's Republic of ChinaReproductive Medicine CenterPeople's Hospital of Zhengzhou University, Zhengzhou, Henan Province 450003, People's Republic of ChinaDepartment of Veterinary PathobiologyUniversity of Missouri, Columbia, Missouri 65211, USA Reproductive Medicine CenterHenan Provincial People's Hospital, #7 Weiwu Road, Jinshui District, Zhengzhou, Henan Province 450003, People's Republic of ChinaState Key Laboratory of Reproductive BiologyInstitute of Zoology, Chinese Academy of Sciences, #1 Beichen West Road, Chaoyang District, Beijing 100101, People's Republic of ChinaReproductive Medicine CenterPeople's Hospital of Zhengzhou University, Zhengzhou, Henan Province 450003, People's Republic of ChinaDepartment of Veterinary PathobiologyUniversity of Missouri, Columbia, Missouri 65211, USA Reproductive Medicine CenterHenan Provincial People's Hospital, #7 Weiwu Road, Jinshui District, Zhengzhou, Henan Province 450003, People's Republic of ChinaState Key Laboratory of Reproductive BiologyInstitute of Zoology, Chinese Academy of Sciences, #1 Beichen West Road, Chaoyang District, Beijing 100101, People's Republic of ChinaReproductive Medicine CenterPeople's Hospital of Zhengzhou University, Zhengzhou, Henan Province 450003, People's Republic of ChinaDepartment of Veterinary PathobiologyUniversity of Missouri, Columbia, Missouri 65211, USA
| | - Heide Schatten
- Reproductive Medicine CenterHenan Provincial People's Hospital, #7 Weiwu Road, Jinshui District, Zhengzhou, Henan Province 450003, People's Republic of ChinaState Key Laboratory of Reproductive BiologyInstitute of Zoology, Chinese Academy of Sciences, #1 Beichen West Road, Chaoyang District, Beijing 100101, People's Republic of ChinaReproductive Medicine CenterPeople's Hospital of Zhengzhou University, Zhengzhou, Henan Province 450003, People's Republic of ChinaDepartment of Veterinary PathobiologyUniversity of Missouri, Columbia, Missouri 65211, USA
| | - Cui-Lian Zhang
- Reproductive Medicine CenterHenan Provincial People's Hospital, #7 Weiwu Road, Jinshui District, Zhengzhou, Henan Province 450003, People's Republic of ChinaState Key Laboratory of Reproductive BiologyInstitute of Zoology, Chinese Academy of Sciences, #1 Beichen West Road, Chaoyang District, Beijing 100101, People's Republic of ChinaReproductive Medicine CenterPeople's Hospital of Zhengzhou University, Zhengzhou, Henan Province 450003, People's Republic of ChinaDepartment of Veterinary PathobiologyUniversity of Missouri, Columbia, Missouri 65211, USA Reproductive Medicine CenterHenan Provincial People's Hospital, #7 Weiwu Road, Jinshui District, Zhengzhou, Henan Province 450003, People's Republic of ChinaState Key Laboratory of Reproductive BiologyInstitute of Zoology, Chinese Academy of Sciences, #1 Beichen West Road, Chaoyang District, Beijing 100101, People's Republic of ChinaReproductive Medicine CenterPeople's Hospital of Zhengzhou University, Zhengzhou, Henan Province 450003, People's Republic of ChinaDepartment of Veterinary PathobiologyUniversity of Missouri, Columbia, Missouri 65211, USA
| | - Qing-Yuan Sun
- Reproductive Medicine CenterHenan Provincial People's Hospital, #7 Weiwu Road, Jinshui District, Zhengzhou, Henan Province 450003, People's Republic of ChinaState Key Laboratory of Reproductive BiologyInstitute of Zoology, Chinese Academy of Sciences, #1 Beichen West Road, Chaoyang District, Beijing 100101, People's Republic of ChinaReproductive Medicine CenterPeople's Hospital of Zhengzhou University, Zhengzhou, Henan Province 450003, People's Republic of ChinaDepartment of Veterinary PathobiologyUniversity of Missouri, Columbia, Missouri 65211, USA
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32
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Ooga M, Suzuki MG, Aoki F. Involvement of DOT1L in the Remodeling of Heterochromatin Configuration During Early Preimplantation Development in Mice1. Biol Reprod 2013; 89:145. [DOI: 10.1095/biolreprod.113.113258] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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33
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Barnetova I, Morovic M, Strejcek F, Østrup O, Hyttel P, Niemann H, Laurincik J, Fulka J, Fulka H. RNA polymerase II transcriptional silencing in growing and fully grown germinal vesicle oocytes isolated from gonadotropin-stimulated and non-stimulated gilts. Mol Reprod Dev 2012; 79:697-708. [DOI: 10.1002/mrd.22077] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 07/17/2012] [Indexed: 11/06/2022]
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34
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Posfai E, Kunzmann R, Brochard V, Salvaing J, Cabuy E, Roloff TC, Liu Z, Tardat M, van Lohuizen M, Vidal M, Beaujean N, Peters AHFM. Polycomb function during oogenesis is required for mouse embryonic development. Genes Dev 2012; 26:920-32. [PMID: 22499591 DOI: 10.1101/gad.188094.112] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In mammals, totipotent embryos are formed by fusion of highly differentiated gametes. Acquisition of totipotency concurs with chromatin remodeling of parental genomes, changes in the maternal transcriptome and proteome, and zygotic genome activation (ZGA). The inefficiency of reprogramming somatic nuclei in reproductive cloning suggests that intergenerational inheritance of germline chromatin contributes to developmental proficiency after natural conception. Here we show that Ring1 and Rnf2, components of Polycomb-repressive complex 1 (PRC1), serve redundant transcriptional functions during oogenesis that are essential for proper ZGA, replication and cell cycle progression in early embryos, and development beyond the two-cell stage. Exchange of chromosomes between control and Ring1/Rnf2-deficient metaphase II oocytes reveal cytoplasmic and chromosome-based contributions by PRC1 to embryonic development. Our results strongly support a model in which Polycomb acts in the female germline to establish developmental competence for the following generation by silencing differentiation-inducing genes and defining appropriate chromatin states.
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Affiliation(s)
- Eszter Posfai
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
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Tian X, Diaz FJ. Zinc depletion causes multiple defects in ovarian function during the periovulatory period in mice. Endocrinology 2012; 153:873-86. [PMID: 22147014 PMCID: PMC3275394 DOI: 10.1210/en.2011-1599] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Shortly before ovulation, the oocyte acquires developmental competence and granulosa cells undergo tremendous changes including cumulus expansion and luteinization. Zinc is emerging as a key regulator of meiosis in vitro, but a complete understanding of zinc-mediated effects during the periovulatory period is lacking. The present study uncovers the previously unknown role of zinc in maintaining meiotic arrest before ovulation. A zinc chelator [N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN)] caused premature germinal vesicle breakdown and associated spindle defects in denuded oocytes even in the presence of a phosphodiesterase 3A inhibitor (milrinone). TPEN also potently blocked cumulus expansion by blocking induction of expansion-related transcripts Has2, Ptx3, Ptgs2, and Tnfaip6 mRNA. Both meiotic arrest and cumulus expansion were rescued by exogenous zinc. Lack of cumulus expansion is due to an almost complete suppression of phospho-Sma- and Mad-related protein 2/3 signaling. Consistent with a decrease in phospho-Sma- and Mad-related protein 2/3 signaling, TPEN also decreased cumulus transcripts (Ar and Slc38a3) and caused a surprising increase in mural transcripts (Lhcgr and Cyp11a1) in cumulus cells. In vivo, feeding a zinc-deficient diet for 10 d completely blocked ovulation and compromised cumulus expansion. However, 42.5% of oocytes had prematurely resumed meiosis before human chorionic gonadotropin injection, underscoring the importance of zinc before ovulation. A more acute 3-d treatment with a zinc-deficient diet did not block ovulation but did increase the number of oocytes trapped in luteinizing follicles. Moreover, 23% of ovulated oocytes did not reach metaphase II due to severe spindle defects. Thus, acute zinc deficiency causes profound defects during the periovulatory period with consequences for oocyte maturation, cumulus expansion, and ovulation.
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Affiliation(s)
- X Tian
- Center for Reproductive Biology and Health, Department of Poultry Science, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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De La Fuente R, Baumann C, Viveiros MM. Chromatin structure and ATRX function in mouse oocytes. Results Probl Cell Differ 2012; 55:45-68. [PMID: 22918800 DOI: 10.1007/978-3-642-30406-4_3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Differentiation of chromatin structure and function during oogenesis is essential to confer the mammalian oocyte with meiotic and developmental potential. Errors in chromosome segregation during female meiosis and subsequent transmission of an abnormal chromosome complement (aneuploidy) to the early conceptus are one of the leading causes of pregnancy loss in women. The chromatin remodeling protein ATRX (α-thalassemia mental retardation X-linked) has recently emerged as a critical factor involved in heterochromatin formation at mammalian centromeres during meiosis. In mammalian oocytes, ATRX binds to centromeric heterochromatin domains where it is required for accurate chromosome segregation. Loss of ATRX function induces abnormal meiotic chromosome morphology, reduces histone H3 phosphorylation, and promotes a high incidence of aneuploidy associated with severely reduced fertility. The presence of centromeric breaks during the transition to the first mitosis in the early embryo indicates that the role of ATRX in chromosome segregation is mediated through an epigenetic mechanism involving the maintenance of chromatin modifications associated with pericentric heterochromatin (PCH) formation and chromosome condensation. This is consistent with the existence of a potential molecular link between centromeric and PCH in the epigenetic control of centromere function and maintenance of chromosome stability in mammalian oocytes. Dissecting the molecular mechanisms of ATRX function during meiosis will have important clinical implications towards uncovering the epigenetic factors contributing to the onset of aneuploidy in the human oocyte.
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Suh N, Blelloch R. Small RNAs in early mammalian development: from gametes to gastrulation. Development 2011; 138:1653-61. [PMID: 21486922 DOI: 10.1242/dev.056234] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Small non-coding RNAs, including microRNAs (miRNAs), endogenous small interfering RNAs (endo-siRNAs) and Piwi-interacting RNAs (piRNAs), play essential roles in mammalian development. The function and timing of expression of these three classes of small RNAs differ greatly. piRNAs are expressed and play a crucial role during male gametogenesis, whereas endo-siRNAs are essential for oocyte meiosis. By contrast, miRNAs are ubiquitously expressed in somatic tissues and function throughout post-implantation development. Surprisingly, however, miRNAs are non-essential during pre-implantation embryonic development and their function is suppressed during oocyte meiosis. Here, we review the roles of small non-coding RNAs during the early stages of mammalian development, from gamete maturation through to gastrulation.
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Affiliation(s)
- Nayoung Suh
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, and Department of Urology, University of California San Francisco, San Francisco, CA 94143, USA
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