1
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Shi DL. Interplay of RNA-binding proteins controls germ cell development in zebrafish. J Genet Genomics 2024; 51:889-899. [PMID: 38969260 DOI: 10.1016/j.jgg.2024.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/26/2024] [Accepted: 06/27/2024] [Indexed: 07/07/2024]
Abstract
The specification of germ cells in zebrafish mostly relies on an inherited mechanism by which localized maternal determinants, called germ plasm, confer germline fate in the early embryo. Extensive studies have partially allowed the identification of key regulators governing germ plasm formation and subsequent germ cell development. RNA-binding proteins, acting in concert with other germ plasm components, play essential roles in the organization of the germ plasm and the specification, migration, maintenance, and differentiation of primordial germ cells. The loss of their functions impairs germ cell formation and causes sterility or sexual conversion. Evidence is emerging that they instruct germline development through differential regulation of mRNA fates in somatic and germ cells. However, the challenge remains to decipher the complex interplay of maternal germ plasm components in germ plasm compartmentalization and germ cell specification. Because failure to control the developmental outcome of germ cells disrupts the formation of gametes, it is important to gain a complete picture of regulatory mechanisms operating in the germ cell lineage. This review sheds light on the contributions of RNA-binding proteins to germ cell development in zebrafish and highlights intriguing questions that remain open for future investigation.
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Affiliation(s)
- De-Li Shi
- Laboratory of Developmental Biology, CNRS-UMR7622, Institut de Biologie Paris-Seine (IBPS), Sorbonne University, 75005 Paris, France.
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2
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Pamula MC, Lehmann R. How germ granules promote germ cell fate. Nat Rev Genet 2024:10.1038/s41576-024-00744-8. [PMID: 38890558 DOI: 10.1038/s41576-024-00744-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2024] [Indexed: 06/20/2024]
Abstract
Germ cells are the only cells in the body capable of giving rise to a new organism, and this totipotency hinges on their ability to assemble membraneless germ granules. These specialized RNA and protein complexes are hallmarks of germ cells throughout their life cycle: as embryonic germ granules in late oocytes and zygotes, Balbiani bodies in immature oocytes, and nuage in maturing gametes. Decades of developmental, genetic and biochemical studies have identified protein and RNA constituents unique to germ granules and have implicated these in germ cell identity, genome integrity and gamete differentiation. Now, emerging research is defining germ granules as biomolecular condensates that achieve high molecular concentrations by phase separation, and it is assigning distinct roles to germ granules during different stages of germline development. This organization of the germ cell cytoplasm into cellular subcompartments seems to be critical not only for the flawless continuity through the germline life cycle within the developing organism but also for the success of the next generation.
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Affiliation(s)
| | - Ruth Lehmann
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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3
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Cohen B, Golani-Armon A, Arava YS. Emerging implications for ribosomes in proximity to mitochondria. Semin Cell Dev Biol 2024; 154:123-130. [PMID: 36642616 DOI: 10.1016/j.semcdb.2023.01.003] [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: 04/29/2022] [Revised: 12/11/2022] [Accepted: 01/05/2023] [Indexed: 01/15/2023]
Abstract
Synthesis of all proteins in eukaryotic cells, apart from a few organellar proteins, is done by cytosolic ribosomes. Many of these ribosomes are localized in the vicinity of the functional site of their encoded protein, enabling local protein synthesis. Studies in various organisms and tissues revealed that such locally translating ribosomes are also present near mitochondria. Here, we provide a brief summary of evidence for localized translation near mitochondria, then present data suggesting that these localized ribosomes may enable local translational regulatory processes in response to mitochondria needs. Finally, we describe the involvement of such localized ribosomes in the quality control of protein synthesis and mitochondria. These emerging views suggest that ribosomes localized near mitochondria are a hub for a variety of activities with diverse implications on mitochondria physiology.
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Affiliation(s)
- Bar Cohen
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Adi Golani-Armon
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Yoav S Arava
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
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4
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Mytlis A, Levy K, Elkouby YM. The many faces of the bouquet centrosome MTOC in meiosis and germ cell development. Curr Opin Cell Biol 2023; 81:102158. [PMID: 36913831 DOI: 10.1016/j.ceb.2023.102158] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 12/28/2022] [Accepted: 02/12/2023] [Indexed: 03/13/2023]
Abstract
Meiotic chromosomal pairing is facilitated by a conserved cytoskeletal organization. Telomeres associate with perinuclear microtubules via Sun/KASH complexes on the nuclear envelope (NE) and dynein. Telomere sliding on perinuclear microtubules contributes to chromosome homology searches and is essential for meiosis. Telomeres ultimately cluster on the NE, facing the centrosome, in a configuration called the chromosomal bouquet. Here, we discuss novel components and functions of the bouquet microtubule organizing center (MTOC) in meiosis, but also broadly in gamete development. The cellular mechanics of chromosome movements and the bouquet MTOC dynamics are striking. The newly identified zygotene cilium mechanically anchors the bouquet centrosome and completes the bouquet MTOC machinery in zebrafish and mice. We hypothesize that various centrosome anchoring strategies evolved in different species. Evidence suggests that the bouquet MTOC machinery is a cellular organizer, linking meiotic mechanisms with gamete development and morphogenesis. We highlight this cytoskeletal organization as a new platform for creating a holistic understanding of early gametogenesis, with direct implications to fertility and reproduction.
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Affiliation(s)
- Avishag Mytlis
- Department of Developmental Biology and Cancer Research, The Hebrew University of Jerusalem Faculty of Medicine, Ein-Kerem Campus, Jerusalem, 9112102, Israel; Institute for Medical Research - Israel-Canada (IMRIC), Ein-Kerem Campus, Jerusalem 9112102, Israel
| | - Karine Levy
- Department of Developmental Biology and Cancer Research, The Hebrew University of Jerusalem Faculty of Medicine, Ein-Kerem Campus, Jerusalem, 9112102, Israel; Institute for Medical Research - Israel-Canada (IMRIC), Ein-Kerem Campus, Jerusalem 9112102, Israel
| | - Yaniv M Elkouby
- Department of Developmental Biology and Cancer Research, The Hebrew University of Jerusalem Faculty of Medicine, Ein-Kerem Campus, Jerusalem, 9112102, Israel; Institute for Medical Research - Israel-Canada (IMRIC), Ein-Kerem Campus, Jerusalem 9112102, Israel.
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5
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Bogoch Y, Jamieson-Lucy A, Vejnar CE, Levy K, Giraldez AJ, Mullins MC, Elkouby YM. Stage Specific Transcriptomic Analysis and Database for Zebrafish Oogenesis. Front Cell Dev Biol 2022; 10:826892. [PMID: 35733854 PMCID: PMC9207522 DOI: 10.3389/fcell.2022.826892] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/11/2022] [Indexed: 01/21/2023] Open
Abstract
Oogenesis produces functional eggs and is essential for fertility, embryonic development, and reproduction. The zebrafish ovary is an excellent model to study oogenesis in vertebrates, and recent studies have identified multiple regulators in oocyte development through forward genetic screens, as well as reverse genetics by CRISPR mutagenesis. However, many developmental steps in oogenesis, in zebrafish and other species, remain poorly understood, and their underlying mechanisms are unknown. Here, we take a genomic approach to systematically uncover biological activities throughout oogenesis. We performed transcriptomic analysis on five stages of oogenesis, from the onset of oocyte differentiation through Stage III, which precedes oocyte maturation. These transcriptomes revealed thousands of differentially expressed genes across stages of oogenesis. We analyzed trends of gene expression dynamics along oogenesis, as well as their expression in pair-wise comparisons between stages. We determined their functionally enriched terms, identifying uniquely characteristic biological activities in each stage. These data identified two prominent developmental phases in oocyte differentiation and traced the accumulation of maternally deposited embryonic regulator transcripts in the developing oocyte. Our analysis provides the first molecular description for oogenesis in zebrafish, which we deposit online as a resource for the community. Further, the presence of multiple gene paralogs in zebrafish, and the exclusive curation by many bioinformatic tools of the single paralogs present in humans, challenge zebrafish genomic analyses. We offer an approach for converting zebrafish gene name nomenclature to the human nomenclature for supporting genomic analyses generally in zebrafish. Altogether, our work provides a valuable resource as a first step to uncover oogenesis mechanisms and candidate regulators and track accumulating transcripts of maternal regulators of embryonic development.
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Affiliation(s)
- Yoel Bogoch
- Department of Developmental Biology and Cancer Research, Hebrew University of Jerusalem Faculty of Medicine, Jerusalem, Israel
- Institute for Biomedical Research, Israel-Canada, Jerusalem, Israel
| | - Allison Jamieson-Lucy
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | | | - Karine Levy
- Department of Developmental Biology and Cancer Research, Hebrew University of Jerusalem Faculty of Medicine, Jerusalem, Israel
- Institute for Biomedical Research, Israel-Canada, Jerusalem, Israel
| | | | - Mary C. Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Yaniv M. Elkouby
- Department of Developmental Biology and Cancer Research, Hebrew University of Jerusalem Faculty of Medicine, Jerusalem, Israel
- Institute for Biomedical Research, Israel-Canada, Jerusalem, Israel
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6
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Jamieson-Lucy AH, Kobayashi M, James Aykit Y, Elkouby YM, Escobar-Aguirre M, Vejnar CE, Giraldez AJ, Mullins MC. A proteomics approach identifies novel resident zebrafish Balbiani body proteins Cirbpa and Cirbpb. Dev Biol 2022; 484:1-11. [PMID: 35065906 PMCID: PMC8967276 DOI: 10.1016/j.ydbio.2022.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 01/11/2022] [Accepted: 01/13/2022] [Indexed: 01/17/2023]
Abstract
The Balbiani body (Bb) is the first marker of polarity in vertebrate oocytes. The Bb is a conserved structure found in diverse animals including insects, fish, amphibians, and mammals. During early zebrafish oogenesis, the Bb assembles as a transient aggregate of mRNA, proteins, and membrane-bound organelles at the presumptive vegetal side of the oocyte. As the early oocyte develops, the Bb appears to grow slowly, until at the end of stage I of oogenesis it disassembles and deposits its cargo of localized mRNAs and proteins. In fish and frogs, this cargo includes the germ plasm as well as gene products required to specify dorsal tissues of the future embryo. We demonstrate that the Bb is a stable, solid structure that forms a size exclusion barrier similar to other biological hydrogels. Despite its central role in oocyte polarity, little is known about the mechanism behind the Bb's action. Analysis of the few known protein components of the Bb is insufficient to explain how the Bb assembles, translocates, and disassembles. We isolated Bbs from zebrafish oocytes and performed mass spectrometry to define the Bb proteome. We successfully identified 77 proteins associated with the Bb sample, including known Bb proteins and novel RNA-binding proteins. In particular, we identified Cirbpa and Cirbpb, which have both an RNA-binding domain and a predicted self-aggregation domain. In stage I oocytes, Cirbpa and Cirbpb localize to the Bb rather than the nucleus (as in somatic cells), indicating that they may have a specialized function in the germ line. Both the RNA-binding domain and the self-aggregation domain are sufficient to localize to the Bb, suggesting that Cirbpa and Cirbpb interact with more than just their mRNA targets within the Bb. We propose that Cirbp proteins crosslink mRNA cargo and proteinaceous components of the Bb as it grows. Beyond Cirbpa and Cirbpb, our proteomics dataset presents many candidates for further study, making it a valuable resource for building a comprehensive mechanism for Bb function at a protein level.
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Affiliation(s)
- Allison H Jamieson-Lucy
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Manami Kobayashi
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Y James Aykit
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Yaniv M Elkouby
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Matias Escobar-Aguirre
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Charles E Vejnar
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Antonio J Giraldez
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Mary C Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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7
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Zhang C, Li J, Tarique I, Zhang Y, Lu T, Wang J, Chen A, Wen F, Zhang Z, Zhang Y, Shao M. A Time-Saving Strategy to Generate Double Maternal Mutants by an Oocyte-Specific Conditional Knockout System in Zebrafish. BIOLOGY 2021; 10:biology10080777. [PMID: 34440009 PMCID: PMC8389640 DOI: 10.3390/biology10080777] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/29/2021] [Accepted: 08/14/2021] [Indexed: 12/23/2022]
Abstract
Simple Summary Maternally supplied mRNAs and proteins, termed maternal factors, are produced by over 14,000 coding genes in zebrafish. They play exclusive roles in controlling the formation of oocytes and the development of early embryos. These maternal factors can also compensate for the loss of function of its corresponding zygotic gene products. Thus, eliminating both maternal and zygotic gene products is essential to elucidate the functions of more than half of zebrafish genes. However, it is always challenging to inactivate maternal factors, because traditional genetic methods are either technically demanding or time-consuming. Our recent work established a rapid conditional knockout method to generate maternal or maternal and zygotic mutants in one fish generation. Here, we further test the feasibility of this approach to knock out two maternal genes with functional redundancy simultaneously. As a proof of principle, we successfully generated double maternal mutant embryos for dvl2 and dvl3a genes in three months for the first time. The cell movement defects in mutant embryos obtained by this approach mimic the genuine mutant embryos generated after fifteen months of time-consuming screening following the previously reported mosaic strategy. Therefore, this method has the potential to speed up the functional study of paralogous maternal genes. Abstract Maternal products are those mRNAs and proteins deposited during oogenesis, which play critical roles in controlling oocyte formation, fertilization, and early embryonic development. However, loss-of-function studies for these maternal factors are still lacking, mainly because of the prolonged period of transgenerational screening and technical barriers that prevent the generation of maternal (M) and maternal and zygotic (MZ) mutant embryos. By the transgenic expression of multiple sgRNAs targeting a single gene of interest in the background of a transgenic line Tg(zpc:zcas9) with oocyte-specific cas9 expression, we have successfully obtained maternal or maternal–zygotic mutant for single genes in F1 embryos. In this work, we tandemly connected a maternal GFP marker and eight sgRNA expression units to target dvl2 and dvl3a simultaneously and introduced this construct to the genome of Tg(zpc:zcas9) by meganuclease I-Sce I. As expected, we confirmed the existence of Mdvl2;Mdvl3a embryos with strong defective convergence and extension movement during gastrulation among outcrossed GFP positive F1 offspring. The MZdvl2;MZdvl3a embryos were also obtained by crossing the mutant carrying mosaic F0 female with dvl2+/−;dvl3a−/− male fish. This proof-of-principle thus highlights the potential of this conditional knockout strategy to circumvent the current difficulty in the study of genes with multiple functionally redundant paralogs.
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Affiliation(s)
- Chong Zhang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (C.Z.); (I.T.); (Y.Z.); (T.L.); (J.W.); (A.C.); (F.W.); (Y.Z.)
| | - Jiaguang Li
- Taishan College, Shandong University, Qingdao 266237, China; (J.L.); (Z.Z.)
| | - Imran Tarique
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (C.Z.); (I.T.); (Y.Z.); (T.L.); (J.W.); (A.C.); (F.W.); (Y.Z.)
| | - Yizhuang Zhang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (C.Z.); (I.T.); (Y.Z.); (T.L.); (J.W.); (A.C.); (F.W.); (Y.Z.)
| | - Tong Lu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (C.Z.); (I.T.); (Y.Z.); (T.L.); (J.W.); (A.C.); (F.W.); (Y.Z.)
| | - Jiasheng Wang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (C.Z.); (I.T.); (Y.Z.); (T.L.); (J.W.); (A.C.); (F.W.); (Y.Z.)
| | - Aijun Chen
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (C.Z.); (I.T.); (Y.Z.); (T.L.); (J.W.); (A.C.); (F.W.); (Y.Z.)
| | - Fenfen Wen
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (C.Z.); (I.T.); (Y.Z.); (T.L.); (J.W.); (A.C.); (F.W.); (Y.Z.)
| | - Zhuoyu Zhang
- Taishan College, Shandong University, Qingdao 266237, China; (J.L.); (Z.Z.)
| | - Yanjun Zhang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (C.Z.); (I.T.); (Y.Z.); (T.L.); (J.W.); (A.C.); (F.W.); (Y.Z.)
| | - Ming Shao
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (C.Z.); (I.T.); (Y.Z.); (T.L.); (J.W.); (A.C.); (F.W.); (Y.Z.)
- Taishan College, Shandong University, Qingdao 266237, China; (J.L.); (Z.Z.)
- Correspondence:
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8
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Zhang C, Lu T, Zhang Y, Li J, Tarique I, Wen F, Chen A, Wang J, Zhang Z, Zhang Y, Shi DL, Shao M. Rapid generation of maternal mutants via oocyte transgenic expression of CRISPR-Cas9 and sgRNAs in zebrafish. SCIENCE ADVANCES 2021; 7:eabg4243. [PMID: 34362733 PMCID: PMC8346210 DOI: 10.1126/sciadv.abg4243] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 06/21/2021] [Indexed: 05/08/2023]
Abstract
Maternal products are exclusive factors to drive oogenesis and early embryonic development. As disrupting maternal gene functions is either time-consuming or technically challenging, early developmental programs regulated by maternal factors remain mostly elusive. We provide a transgenic approach to inactivate maternal genes in zebrafish primary oocytes. By introducing three tandem single guide RNA (sgRNA) expression cassettes and a green fluorescent protein (GFP) reporter into Tg(zpc:zcas9) embryos, we efficiently obtained maternal nanog and ctnnb2 mutants among GFP-positive F1 offspring. Notably, most of these maternal mutants displayed either sgRNA site-spanning genomic deletions or unintended large deletions extending distantly from the sgRNA targets, suggesting a prominent deletion-prone tendency of genome editing in the oocyte. Thus, our method allows maternal gene knockout in the absence of viable and fertile homozygous mutant adults. This approach is particularly time-saving and can be applied for functional screening of maternal factors and generating genomic deletions in zebrafish.
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Affiliation(s)
- Chong Zhang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Tong Lu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Yizhuang Zhang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Jiaguang Li
- Shandong University Taishan College, Qingdao 266237, China
| | - Imran Tarique
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Fenfen Wen
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Aijun Chen
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Jiasheng Wang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Zhuoyu Zhang
- Shandong University Taishan College, Qingdao 266237, China
| | - Yanjun Zhang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - De-Li Shi
- Affiliated Hospital of Guangdong Medical University, Zhanjiang 524001, China
- Developmental Biology Laboratory, CNRS-UMR7622, Institut de Biologie Paris-Seine, Sorbonne University, Paris 75005, France
| | - Ming Shao
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China.
- Shandong University Taishan College, Qingdao 266237, China
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9
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Voronina AS, Pshennikova ES. mRNPs: Structure and role in development. Cell Biochem Funct 2021; 39:832-843. [PMID: 34212408 DOI: 10.1002/cbf.3656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/05/2021] [Accepted: 06/17/2021] [Indexed: 11/11/2022]
Abstract
In eukaryotic cells, mRNA molecules are coated with numerous RNA-binding proteins and so exist in ribonucleoproteins (mRNPs). The proteins associated with the mRNA regulate the fate of mRNA, including its localization, translation and decay. Before activation of translation, the mRNA does not display any template functions-it is masked. The coordinated activity of certain RNA-binding proteins determines the future fate of each mRNA individually. In embryo development, the temporal and spatial regulation of translation can cause a situation when the mRNA and the encoded protein are localized in different compartments and so the differentiation of the cells can be determined. The fundamentals of regulation of the mRNAs fate and functioning in nerves are similar to those already described for oo- and embryogenesis. Disorders in the mRNA masking and demasking result in the emergence of various diseases, in particular cancers and neuro-degenerative diseases.
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Affiliation(s)
- Anna S Voronina
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Elena S Pshennikova
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
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10
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Ren F, Miao R, Xiao R, Mei J. m 6A reader Igf2bp3 enables germ plasm assembly by m 6A-dependent regulation of gene expression in zebrafish. Sci Bull (Beijing) 2021; 66:1119-1128. [PMID: 36654345 DOI: 10.1016/j.scib.2021.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 09/13/2020] [Accepted: 10/27/2020] [Indexed: 01/20/2023]
Abstract
Bucky ball (Buc) is involved in germ plasm (GP) assembly during early zebrafish development by regulating GP mRNA expression via an unknown mechanism. The present study demonstrates that an m6A reader Igf2bp3 interacts and colocalizes with Buc in the GP. Similar to the loss of Buc, the genetic deletion of maternal igf2bp3 in zebrafish leads to abnormal GP assembly and insufficient germ cell specification, which can be partially restored by the injection of igf2bp3 mRNA. Igf2bp3 binds to m6A-modified GP-organizer and GP mRNAs in an m6A-dependent manner and prevents their degradation. These findings indicate that the functions of Igf2bp3, a direct effector protein of Buc, in GP mRNA expression and GP assembly involve m6A-dependent regulation; these results emphasize a critical role of m6A modification in the process of GP assembly.
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Affiliation(s)
- Fan Ren
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Ran Miao
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Rui Xiao
- Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Wuhan University, Wuhan 430071, China; Department of Hematology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, China.
| | - Jie Mei
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
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11
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Holler K, Neuschulz A, Drewe-Boß P, Mintcheva J, Spanjaard B, Arsiè R, Ohler U, Landthaler M, Junker JP. Spatio-temporal mRNA tracking in the early zebrafish embryo. Nat Commun 2021; 12:3358. [PMID: 34099733 PMCID: PMC8184788 DOI: 10.1038/s41467-021-23834-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 05/18/2021] [Indexed: 01/17/2023] Open
Abstract
Early stages of embryogenesis depend on subcellular localization and transport of maternal mRNA. However, systematic analysis of these processes is hindered by a lack of spatio-temporal information in single-cell RNA sequencing. Here, we combine spatially-resolved transcriptomics and single-cell RNA labeling to perform a spatio-temporal analysis of the transcriptome during early zebrafish development. We measure spatial localization of mRNA molecules within the one-cell stage embryo, which allows us to identify a class of mRNAs that are specifically localized at an extraembryonic position, the vegetal pole. Furthermore, we establish a method for high-throughput single-cell RNA labeling in early zebrafish embryos, which enables us to follow the fate of individual maternal transcripts until gastrulation. This approach reveals that many localized transcripts are specifically transported to the primordial germ cells. Finally, we acquire spatial transcriptomes of two xenopus species and compare evolutionary conservation of localized genes as well as enriched sequence motifs.
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Affiliation(s)
- Karoline Holler
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Anika Neuschulz
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Philipp Drewe-Boß
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Janita Mintcheva
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Bastiaan Spanjaard
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Roberto Arsiè
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Uwe Ohler
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Department of Biology, Humboldt University, Berlin, Germany
| | - Markus Landthaler
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- IRI Life Science, Institute of Biology, Humboldt University, Berlin, Germany
| | - Jan Philipp Junker
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
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12
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Mytlis A, Elkouby YM. Live and Time-Lapse Imaging of Early Oogenesis and Meiotic Chromosomal Dynamics in Cultured Juvenile Zebrafish Ovaries. Methods Mol Biol 2021; 2218:137-155. [PMID: 33606229 DOI: 10.1007/978-1-0716-0970-5_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Oocyte production is crucial for sexual reproduction. Recent findings in zebrafish and other established model organisms emphasize that the early steps of oogenesis involve the coordination of simultaneous and tightly sequential processes across cellular compartments and between sister cells. To fully understand the mechanistic framework of these coordinated processes, cellular and morphological analysis in high temporal resolution is required. Here, we provide a protocol for four-dimensional live time-lapse analysis of cultured juvenile zebrafish ovaries. We describe how multiple-stage oocytes can be simultaneously analyzed in single ovaries, and several ovaries can be processed in single experiments. In addition, we detail adequate conditions for quantitative image acquisition. Finally, we demonstrate that using this protocol, we successfully capture rapid meiotic chromosomal movements in early prophase for the first time in zebrafish oocytes, in four dimensions and in vivo. Our protocol expands the use of the zebrafish as a model system to understand germ cell and ovarian development in postembryonic stages.
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Affiliation(s)
- Avishag Mytlis
- Department of Developmental Biology and Cancer Research, The Hebrew University of Jerusalem, Faculty of Medicine, Institute for Medical Research - Israel-Canada (IMRIC), Jerusalem, Israel
| | - Yaniv M Elkouby
- Department of Developmental Biology and Cancer Research, The Hebrew University of Jerusalem, Faculty of Medicine, Institute for Medical Research - Israel-Canada (IMRIC), Jerusalem, Israel.
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13
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Żelazowska M, Halajian A. Asymmetry in the cytoplasm of oocytes of largescale yellowfish Labeobarbus marequensis Smith 1841 (Teleostei: Cypriniformes: Cyprinidae). J Morphol 2020; 281:997-1009. [PMID: 32562511 DOI: 10.1002/jmor.21228] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 04/13/2020] [Accepted: 06/05/2020] [Indexed: 11/08/2022]
Abstract
The ovaries of the largescale yellowfish, Labeobarbus marequensis (Teleostei: Cypriniformes: Cyprinidae), are made up of the germinal epithelium, nests of late chromatin nucleolus stage oocytes, and ovarian follicles. Each follicle is composed of a single oocyte, which is surrounded by somatic follicular cells and a basal lamina covered by thecal cells. We describe polarization and ultrastructure of oocytes during the primary growth stage. The oocyte nucleus contains lampbrush chromosomes, nuclear bodies and fibrillar material in which multiple nucleoli arise. Nuage aggregations composed of material of a nuclear origin are present in the perinuclear cytoplasm. The Balbiani body (Bb) contains aggregations of nuage, rough endoplasmic reticulum, individual mitochondria and complexes of mitochondria with nuage (cement). Some mitochondria in the Bb come into close contact with endoplasmic reticulum cisternae and vesicles that contain granular material. At the start of primary growth, the Bb is present in the cytoplasm close to the nucleus. Next, it expands towards the oocyte plasma membrane. In these oocytes, a spherical structure, the so-called yolk nucleus, arises in the Bb. It consists of granular nuage in which mitochondria and vesicles containing granular material are immersed. Later, the Bb becomes fragmented and a fully grown yolk nucleus is present in the vegetal region. It contains numerous threads composed of granular nuage, mitochondria, lysosome-like organelles and autophagosomes. We discuss the formation of autophagosomes in the cytoplasm of primary growth oocytes. During the final step of primary growth, the cortical alveoli arise in the cytoplasm and are distributed evenly. The eggshell is deposited on the external surface of the oocyte plasma membrane and is made up of two egg envelopes that are pierced by numerous pore canals. The external egg envelope is covered in protuberances. During primary growth no lipid droplets are synthesized or stored in the oocytes.
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Affiliation(s)
- Monika Żelazowska
- Department of Developmental Biology and Morphology of Invertebrates, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Ali Halajian
- DST-NRF SARChI Research Chair (Ecosystem Health), Department of Biodiversity, University of Limpopo, Sovenga, 0727, South Africa
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14
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Abstract
Gastrulation is a critical early morphogenetic process of animal development, during which the three germ layers; mesoderm, endoderm and ectoderm, are rearranged by internalization movements. Concurrent epiboly movements spread and thin the germ layers while convergence and extension movements shape them into an anteroposteriorly elongated body with head, trunk, tail and organ rudiments. In zebrafish, gastrulation follows the proliferative and inductive events that establish the embryonic and extraembryonic tissues and the embryonic axis. Specification of these tissues and embryonic axes are controlled by the maternal gene products deposited in the egg. These early maternally controlled processes need to generate sufficient cell numbers and establish the embryonic polarity to ensure normal gastrulation. Subsequently, after activation of the zygotic genome, the zygotic gene products govern mesoderm and endoderm induction and germ layer patterning. Gastrulation is initiated during the maternal-to-zygotic transition, a process that entails both activation of the zygotic genome and downregulation of the maternal transcripts. Genomic studies indicate that gastrulation is largely controlled by the zygotic genome. Nonetheless, genetic studies that investigate the relative contributions of maternal and zygotic gene function by comparing zygotic, maternal and maternal zygotic mutant phenotypes, reveal significant contribution of maternal gene products, transcripts and/or proteins, that persist through gastrulation, to the control of gastrulation movements. Therefore, in zebrafish, the maternally expressed gene products not only set the stage for, but they also actively participate in gastrulation morphogenesis.
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Affiliation(s)
- Lilianna Solnica-Krezel
- Department of Developmental Biology and Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, United States.
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15
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Mallam AL, Sae-Lee W, Schaub JM, Tu F, Battenhouse A, Jang YJ, Kim J, Wallingford JB, Finkelstein IJ, Marcotte EM, Drew K. Systematic Discovery of Endogenous Human Ribonucleoprotein Complexes. Cell Rep 2019; 29:1351-1368.e5. [PMID: 31665645 PMCID: PMC6873818 DOI: 10.1016/j.celrep.2019.09.060] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 08/30/2019] [Accepted: 09/18/2019] [Indexed: 12/16/2022] Open
Abstract
RNA-binding proteins (RBPs) play essential roles in biology and are frequently associated with human disease. Although recent studies have systematically identified individual RNA-binding proteins, their higher-order assembly into ribonucleoprotein (RNP) complexes has not been systematically investigated. Here, we describe a proteomics method for systematic identification of RNP complexes in human cells. We identify 1,428 protein complexes that associate with RNA, indicating that more than 20% of known human protein complexes contain RNA. To explore the role of RNA in the assembly of each complex, we identify complexes that dissociate, change composition, or form stable protein-only complexes in the absence of RNA. We use our method to systematically identify cell-type-specific RNA-associated proteins in mouse embryonic stem cells and finally, distribute our resource, rna.MAP, in an easy-to-use online interface (rna.proteincomplexes.org). Our system thus provides a methodology for explorations across human tissues, disease states, and throughout all domains of life.
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Affiliation(s)
- Anna L Mallam
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
| | - Wisath Sae-Lee
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey M Schaub
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Fan Tu
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Anna Battenhouse
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Yu Jin Jang
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Jonghwan Kim
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - John B Wallingford
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Edward M Marcotte
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
| | - Kevin Drew
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
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16
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King SA, Liu H, Wu X. Biomedical potential of mammalian spectraplakin proteins: Progress and prospect. Exp Biol Med (Maywood) 2019; 244:1313-1322. [PMID: 31398993 DOI: 10.1177/1535370219864920] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The cytoskeleton is an essential element of a eukaryotic cell which informs both form and function and ultimately has physiological consequences for the organism. Equally as important as the major cytoskeletal networks are crosslinkers which coordinate and regulate their activities. One such category of crosslinker is the spectraplakins, a family of giant, evolutionarily conserved crosslinking proteins with the rare ability to interact with each of the three major cytoskeletal networks. In particular, a mammalian spectraplakin isotype called MACF1 (microtubule actin crosslinking factor 1), also known as ACF7 (actin crosslinking factor 7), has been of particular interest in the years since its discovery; MACF1 has come under such scrutiny due to the mounting list of biological phenomena in which it has been implicated. This review is an overview of the current knowledge on the structure and function of the known spectraplakin isotypes with an emphasis on MACF1, recent studies on MACF1, and finally, an analysis of the potential of MACF1 to advance medicine. Impact statement Spectraplakins are a highly conserved group of proteins which have the rare ability to bind to each of the three major cytoskeletal networks. The mammalian spectraplakin MACF1/ACF7 has proven to be instrumental in many cellular processes (e.g. signaling and cell migration) since its identification and, as such, has been the focus of various research studies. This review is a synthesis of scientific reports on the structure, confirmed functions, and implicated roles of MACF1/ACF7 as of 2019. Based on what has been revealed thus far in terms of MACF1/ACF7’s role in complex pathologies such as metastatic cancers and inflammatory bowel disease, it appears that MACF1/ACF7 and the continued study thereof hold great potential to both enhance the design of future therapies for various diseases and vastly expand scientific understanding of organismal physiology as a whole.
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Affiliation(s)
- Sarah A King
- Ben May Department for Cancer Research, the University of Chicago, Chicago, IL 60637, USA
| | - Han Liu
- Ben May Department for Cancer Research, the University of Chicago, Chicago, IL 60637, USA
- Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiaoyang Wu
- Ben May Department for Cancer Research, the University of Chicago, Chicago, IL 60637, USA
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17
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Jamieson-Lucy A, Mullins MC. Isolation of Zebrafish Balbiani Bodies for Proteomic Analysis. Methods Mol Biol 2019; 1920:295-302. [PMID: 30737698 DOI: 10.1007/978-1-4939-9009-2_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Proteomic characterization of isolated organelles can provide insight into the functional components of the structure and novel targets for further testing. Germplasm in developing oocytes is difficult to isolate for protein identification because not all types of germplasm are stable outside of the cytoplasm. In zebrafish, the Balbiani body forms a proteinaceous aggregate that contains the germplasm and we found is stable outside of the oocyte. Here we present a manual isolation protocol that collects intact Balbiani bodies from stage I zebrafish oocytes. We lysed oocytes by passing them through a syringe, and then used a fine injection needle to wick up Balbiani bodies by capillary action with minimal buffer solution. Using this protocol we collected sufficient material for proteomic analysis of the zebrafish Balbiani body.
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Affiliation(s)
- Allison Jamieson-Lucy
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mary C Mullins
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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18
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Jamieson-Lucy A, Mullins MC. The vertebrate Balbiani body, germ plasm, and oocyte polarity. Curr Top Dev Biol 2019; 135:1-34. [DOI: 10.1016/bs.ctdb.2019.04.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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19
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Fuentes R, Mullins MC, Fernández J. Formation and dynamics of cytoplasmic domains and their genetic regulation during the zebrafish oocyte-to-embryo transition. Mech Dev 2018; 154:259-269. [PMID: 30077623 DOI: 10.1016/j.mod.2018.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/01/2018] [Indexed: 12/13/2022]
Abstract
Establishment and movement of cytoplasmic domains is of great importance for the emergence of cell polarity, germline segregation, embryonic axis specification and correct sorting of organelles and macromolecules into different embryonic cells. The zebrafish oocyte, egg and zygote are valuable material for the study of cytoplasmic domains formation and dynamics during development. In this review we examined how cytoplasmic domains form and are relocated during zebrafish early embryogenesis. Distinct cortical cytoplasmic domains (also referred to as ectoplasm domains) form first during early oogenesis by the localization of mRNAs to the vegetal or animal poles of the oocyte or radially throughout the cortex. Cytoplasmic segregation in the late oocyte relocates non-cortical cytoplasm (endoplasm) into the preblastodisc and yolk cell. The preblastodisc is a precursor to the blastodisc, which gives rise to the blastoderm and most the future embryo. After egg activation, the blastodisc enlarges by transport of cytoplasm from the yolk cell to the animal pole, along defined pathways or streamers that include a complex cytoskeletal meshwork and cytoplasmic movement at different speeds. A powerful actin ring, assembled at the margin of the blastodisc, appears to drive the massive streaming of cytoplasm. The fact that the mechanism(s) leading to the formation and relocation of cytoplasmic domains are affected in maternal-effect mutants indicates that these processes are under maternal control. Here, we also discuss why these mutants represent outstanding genetic entry points to investigate the genetic basis of cytoplasmic segregation. Functional studies, combined with the analysis of zebrafish mutants, generated by forward and reverse genetic strategies, are expected to decipher the molecular mechanism(s) by which the maternal factors regulate cytoplasmic movements during early vertebrate development.
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Affiliation(s)
- Ricardo Fuentes
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mary C Mullins
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Juan Fernández
- Department of Biology, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
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20
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Elkouby YM, Mullins MC. Coordination of cellular differentiation, polarity, mitosis and meiosis - New findings from early vertebrate oogenesis. Dev Biol 2017; 430:275-287. [PMID: 28666956 DOI: 10.1016/j.ydbio.2017.06.029] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 06/23/2017] [Accepted: 06/26/2017] [Indexed: 12/21/2022]
Abstract
A mechanistic dissection of early oocyte differentiation in vertebrates is key to advancing our knowledge of germline development, reproductive biology, the regulation of meiosis, and all of their associated disorders. Recent advances in the field include breakthroughs in the identification of germline stem cells in Medaka, in the cellular architecture of the germline cyst in mice, in a mechanistic dissection of chromosomal pairing and bouquet formation in meiosis in mice, in tracing oocyte symmetry breaking to the chromosomal bouquet of meiosis in zebrafish, and in the biology of the Balbiani body, a universal oocyte granule. Many of the major events in early oogenesis are universally conserved, and some are co-opted for species-specific needs. The chromosomal events of meiosis are of tremendous consequence to gamete formation and have been extensively studied. New light is now being shed on other aspects of early oocyte differentiation, which were traditionally considered outside the scope of meiosis, and their coordination with meiotic events. The emerging theme is of meiosis as a common groundwork for coordinating multifaceted processes of oocyte differentiation. In an accompanying manuscript we describe methods that allowed for investigations in the zebrafish ovary to contribute to these breakthroughs. Here, we review these advances mostly from the zebrafish and mouse. We discuss oogenesis concepts across established model organisms, and construct an inclusive paradigm for early oocyte differentiation in vertebrates.
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Affiliation(s)
- Yaniv M Elkouby
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Mary C Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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21
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Methods for the analysis of early oogenesis in Zebrafish. Dev Biol 2016; 430:310-324. [PMID: 27988227 DOI: 10.1016/j.ydbio.2016.12.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 11/03/2016] [Accepted: 12/07/2016] [Indexed: 12/22/2022]
Abstract
Oocyte differentiation is a highly dynamic and intricate developmental process whose mechanistic understanding advances female reproduction, fertility, and ovarian cancer biology. Despite the many attributes of the zebrafish model, it has yet to be fully exploited for the investigation of early oocyte differentiation and ovarian development. This is partly because the properties of the adult zebrafish ovary make it technically challenging to access early stage oocytes. As a result, characterization of these stages has been lacking and tools for their analysis have been insufficient. To overcome these technical hurdles, we took advantage of the juvenile zebrafish ovary, where early stage oocytes can readily be found in high numbers and progress in a predictable manner. We characterized the earliest stages of oocyte differentiation and ovarian development and defined accurate staging criteria. We further developed protocols for quantitative microscopy, live time-lapse imaging, ovarian culture, and isolation of stage-specific oocytes for biochemical analysis. These methods have recently provided us with an unprecedented view of early oogenesis, allowing us to study formation of the Balbiani body, a universal oocyte granule that is associated with oocyte survival in mice and required for oocyte and egg polarity in fish and frogs. Despite its tremendous developmental significance, the Bb has been little investigated and how it forms was unknown in any species for over two centuries. We were able to trace Balbiani body formation and oocyte symmetry breaking to the onset of meiosis. Through this investigation we revealed novel cytoskeletal structures in oocytes and the contribution of specialized cellular organization to differentiation. Overall, the juvenile zebrafish ovary arises as an exciting model for studies of cell and developmental biology. We review these and other recent advances in vertebrate oogenesis in an accompanying manuscript in this issue of Developmental Biology. Here, we describe the protocols for ovarian investigation that we developed in the zebrafish, including all experimental steps that will easily allow others to reproduce such analysis. This juvenile ovary toolbox also contributes to establishing the zebrafish as a model for post-larval developmental stages.
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