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Konduktorova VV, Luchinskaya NN, Belyavsky AV. Expression of the Germes Germ Plasm Gene in Follicular Cells of X. laevis Oocytes. Russ J Dev Biol 2022. [DOI: 10.1134/s1062360422050034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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2
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Paraiso KD, Blitz IL, Coley M, Cheung J, Sudou N, Taira M, Cho KWY. Endodermal Maternal Transcription Factors Establish Super-Enhancers during Zygotic Genome Activation. Cell Rep 2020; 27:2962-2977.e5. [PMID: 31167141 PMCID: PMC6610736 DOI: 10.1016/j.celrep.2019.05.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 03/30/2019] [Accepted: 05/01/2019] [Indexed: 01/06/2023] Open
Abstract
Elucidation of the sequence of events underlying the dynamic interaction
between transcription factors and chromatin states is essential. Maternal
transcription factors function at the top of the regulatory hierarchy to specify
the primary germ layers at the onset of zygotic genome activation (ZGA). We
focus on the formation of endoderm progenitor cells and examine the interactions
between maternal transcription factors and chromatin state changes underlying
the cell specification process. Endoderm-specific factors Otx1 and Vegt together
with Foxh1 orchestrate endoderm formation by coordinated binding to select
regulatory regions. These interactions occur before the deposition of enhancer
histone marks around the regulatory regions, and these TFs recruit RNA
polymerase II, regulate enhancer activity, and establish super-enhancers
associated with important endodermal genes. Therefore, maternal transcription
factors Otx1, Vegt, and Foxh1 combinatorially regulate the activity of
super-enhancers, which in turn activate key lineage-specifying genes during
ZGA. How do maternal transcription factors interact with chromatin regions to
coordinate the endodermal gene regulatory program? Paraiso et al. demonstrate
that combinatorial binding of maternal Otx1, Vegt, and Foxh1 to select enhancers
and super-enhancers in the genome controls endodermal cell fate specification
during zygotic gene activation.
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Affiliation(s)
- Kitt D Paraiso
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA; Center for Complex Biological Systems, University of California, Irvine, CA, USA
| | - Ira L Blitz
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Masani Coley
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Jessica Cheung
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Norihiro Sudou
- Department of Anatomy, Tokyo Women's Medical University, Tokyo, Japan
| | - Masanori Taira
- Department of Biological Sciences, Chuo University, Tokyo, Japan
| | - Ken W Y Cho
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA; Center for Complex Biological Systems, University of California, Irvine, CA, USA.
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Paraiso KD, Cho JS, Yong J, Cho KWY. Early Xenopus gene regulatory programs, chromatin states, and the role of maternal transcription factors. Curr Top Dev Biol 2020; 139:35-60. [PMID: 32450966 PMCID: PMC11344482 DOI: 10.1016/bs.ctdb.2020.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
For decades, the early development of the Xenopus embryo has been an essential model system to study the gene regulatory mechanisms that govern cellular specification. At the top of the hierarchy of gene regulatory networks, maternally deposited transcription factors initiate this process and regulate the expression of zygotic genes that give rise to three distinctive germ layer cell types (ectoderm, mesoderm, and endoderm), and subsequent generation of organ precursors. The onset of germ layer specification is also closely coupled with changes associated with chromatin modifications. This review will examine the timing of maternal transcription factors initiating the zygotic genome activation, the epigenetic landscape of embryonic chromatin, and the network structure that governs the process.
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Affiliation(s)
- Kitt D Paraiso
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States; Center for Complex Biological Systems, University of California, Irvine, CA, United States
| | - Jin S Cho
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States
| | - Junseok Yong
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States
| | - Ken W Y Cho
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States; Center for Complex Biological Systems, University of California, Irvine, CA, United States.
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4
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Regulation of cell polarity and RNA localization in vertebrate oocytes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:127-85. [PMID: 24016525 DOI: 10.1016/b978-0-12-407694-5.00004-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
It has long been appreciated that the inheritance of maternal cytoplasmic determinants from different regions of the egg can lead to differential specification of blastomeres during cleavage. Localized RNAs are important determinants of cell fate in eggs and embryos but are also recognized as fundamental regulators of cell structure and function. This chapter summarizes recent molecular and genetic experiments regarding: (1) mechanisms that regulate polarity during different stages of vertebrate oogenesis, (2) pathways that localize presumptive protein and RNA determinants within the polarized oocyte and egg, and (3) how these determinants act in the embryo to determine the ultimate cell fates. Emphasis is placed on studies done in Xenopus, where extensive work has been done in these areas, and comparisons are drawn with fish and mammals. The prospects for future work using in vivo genome manipulation and other postgenomic approaches are also discussed.
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King ML, Messitt TJ, Mowry KL. Putting RNAs in the right place at the right time: RNA localization in the frog oocyte. Biol Cell 2012; 97:19-33. [PMID: 15601255 DOI: 10.1042/bc20040067] [Citation(s) in RCA: 243] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Localization of maternal mRNAs in many developing organisms provides the basis for both initial polarity during oogenesis and patterning during embryogenesis. Prominent examples of this phenomenon are found in Xenopus laevis, where localized maternal mRNAs generate developmental polarity along the animal/vegetal axis. Targeting of mRNA molecules to specific subcellular regions is a fundamental mechanism for spatial regulation of gene expression, and considerable progress has been made in defining the underlying molecular pathways.
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Affiliation(s)
- Mary Lou King
- Department of Cell Biology and Anatomy, University of Miami School of Medicine, 1011 NW 15th St., Miami, FL 33136, USA.
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6
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Schisa JA. New insights into the regulation of RNP granule assembly in oocytes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 295:233-89. [PMID: 22449492 DOI: 10.1016/b978-0-12-394306-4.00013-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In a variety of cell types in plants, animals, and fungi, ribonucleoprotein (RNP) complexes play critical roles in regulating RNA metabolism. These RNP granules include processing bodies and stress granules that are found broadly across cell types, as well as RNP granules unique to the germline, such as P granules, polar granules, sponge bodies, and germinal granules. This review focuses on RNP granules localized in oocytes of the major model systems, Caenorhabditis elegans, Drosophila, Xenopus, mouse, and zebrafish. The signature families of proteins within oocyte RNPs include Vasa and other RNA-binding proteins, decapping activators and enzymes, Argonaute family proteins, and translation initiation complex proteins. This review describes the many recent insights into the dynamics and functions of RNP granules, including their roles in mRNA degradation, mRNA localization, translational regulation, and fertility. The roles of the cytoskeleton and cell organelles in regulating RNP granule assembly are also discussed.
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Affiliation(s)
- Jennifer A Schisa
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan, USA
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7
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Cuykendall TN, Houston DW. Identification of germ plasm-associated transcripts by microarray analysis of Xenopus vegetal cortex RNA. Dev Dyn 2010; 239:1838-48. [PMID: 20503379 DOI: 10.1002/dvdy.22304] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
RNA localization is a common mechanism for regulating cell structure and function. Localized RNAs in Xenopus oocytes are critical for early development, including germline specification by the germ plasm. Despite the importance of these localized RNAs, only approximately 25 have been identified and fewer are functionally characterized. Using microarrays, we identified a large set of localized RNAs from the vegetal cortex. Overall, our results indicate a minimum of 275 localized RNAs in oocytes, or 2-3% of maternal transcripts, which are in general agreement with previous findings. We further validated vegetal localization for 24 candidates and further characterized three genes expressed in the germ plasm. We identified novel germ plasm expression for reticulon 3.1, exd2 (a novel exonuclease-domain encoding gene), and a putative noncoding RNA. Further analysis of these and other localized RNAs will likely identify new functions of germ plasm and facilitate the identification of cis-acting RNA localization elements.
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Affiliation(s)
- Tawny N Cuykendall
- The University of Iowa, Department of Biology, Iowa City, Iowa 52242-1324, USA
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8
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Arthur PK, Claussen M, Koch S, Tarbashevich K, Jahn O, Pieler T. Participation of Xenopus Elr-type proteins in vegetal mRNA localization during oogenesis. J Biol Chem 2009; 284:19982-92. [PMID: 19458392 DOI: 10.1074/jbc.m109.009928] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Directional transport of specific mRNAs is of primary biological relevance. In Xenopus oocytes, mRNA localization to the vegetal pole is important for germ layer formation and germ cell development. Using a biochemical approach, we identified Xenopus Elr-type proteins, homologs of the Hu/ELAV proteins, as novel components of the vegetal mRNA localization machinery. They bind specifically to the localization elements of several different vegetally localizing Xenopus mRNAs, and they are part of one RNP together with other localization proteins, such as Vg1RBP and XStaufen 1. Blocking Elr-type protein binding by either localization element mutagenesis or antisense morpholino oligonucleotide-mediated masking of their target RNA structures, as well as overexpression of wild type and mutant ElrB proteins, interferes with vegetal localization in Xenopus oocytes.
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Affiliation(s)
- Patrick K Arthur
- Department of Developmental Biochemistry, Göttingen Center for Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
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9
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Suda Y, Kurokawa D, Takeuchi M, Kajikawa E, Kuratani S, Amemiya C, Aizawa S. Evolution of Otx paralogue usages in early patterning of the vertebrate head. Dev Biol 2008; 325:282-95. [PMID: 18848537 DOI: 10.1016/j.ydbio.2008.09.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 09/10/2008] [Accepted: 09/12/2008] [Indexed: 11/17/2022]
Abstract
To assess evolutional changes in the expression pattern of Otx paralogues, expression analyses were undertaken in fugu, bichir, skate and lamprey. Together with those in model vertebrates, the comparison suggested that a gnathostome ancestor would have utilized all of Otx1, Otx2 and Otx5 paralogues in organizer and anterior mesendoderm for head development. In this animal, Otx1 and Otx2 would have also functioned in specification of the anterior neuroectoderm at presomite stage and subsequent development of forebrain/midbrain at somite stage, while Otx5 expression would have already been specialized in epiphysis and eyes. Otx1 and Otx2 functions in anterior neuroectoderm and brain of the gnathostome ancestor would have been differentially maintained by Otx1 in a basal actinopterygian and by Otx2 in a basal sarcopterygian. Otx5 expression in head organizer and anterior mesendoderm seems to have been lost in the teleost lineage after divergence of bichir, and also from the amniotes after divergence of amphibians as independent events. Otx1 expression was lost from the organizer in the tetrapod lineage. In contrast, in a teleost ancestor prior to whole genome duplication, Otx1 and Otx2 would have both been expressed in the dorsal margin of blastoderm, embryonic shield, anterior mesendoderm, anterior neuroectoderm and forebrain/midbrain, at respective stages of head development. Subsequent whole genome duplication and the following genome changes would have caused different Otx paralogue usages in each teleost lineage. Lampreys also have three Otx paralogues; their sequences are highly diverged from gnathostome cognates, but their expression pattern is well related to those of skate Otx cognates.
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Affiliation(s)
- Yoko Suda
- Laboratory for Vertebrate Body Plan, Center for Developmental Biology, RIKEN Kobe, Chuo-ku, Kobe 650-0047, Japan
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10
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Kataoka K, Tazaki A, Kitayama A, Ueno N, Watanabe K, Mochii M. Identification of asymmetrically localized transcripts along the animal-vegetal axis of the Xenopus egg. Dev Growth Differ 2008; 47:511-21. [PMID: 16287483 DOI: 10.1111/j.1440-169x.2005.00826.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In many organisms, proper embryo development depends on the asymmetrical distribution of mRNA in the cytoplasm of the egg. Here we report comprehensive screening of RNA localized in the animal or vegetal hemisphere of the Xenopus egg. Macroarrays including over 40,000 independent embryonic cDNA clones, representing at least 17,000 unigenes, were differentially hybridized with labeled probes synthesized from the mRNA of animal or vegetal blastomeres. After two rounds of screening, we identified 33 clones of transcripts that may be preferentially distributed in the vegetal region of the early stage embryo, but transcripts localized in the animal region were not found. To assess the array results, we performed northern blot and quantitative real-time reverse transcription-polymerase chain reaction analysis. As a result, 21 transcripts of the 33 were confirmed to be localized in the vegetal region of the early stage embryo. Whole-mount in situ hybridization analysis revealed that 11 transcripts, including 7 previously reported genes, were localized in the vegetal hemisphere of the egg. These 11 transcripts were categorized into three groups according to their expression patterns in the egg. The first group, which contained four transcripts, showed uniform expression in the vegetal hemisphere, similar to VegT. The second group, which contained three transcripts, showed gradual expression from the vegetal pole to the equator, similar to Vg1. The last group, which contained three transcripts, was expressed at the germ plasm, similar to Xdazl. One transcript, Xwnt11, showed both the second and the third expression patterns.
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Affiliation(s)
- Kensuke Kataoka
- Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Akou 678-1297, Japan.
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11
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Freeman SD, Moore WM, Guiral EC, Holme AD, Turnbull JE, Pownall ME. Extracellular regulation of developmental cell signaling by XtSulf1. Dev Biol 2008; 320:436-45. [PMID: 18617162 DOI: 10.1016/j.ydbio.2008.05.554] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Revised: 05/28/2008] [Accepted: 05/28/2008] [Indexed: 02/06/2023]
Abstract
Heparan sulfate proteoglycans (HSPGs) are synthesised and modified in the Golgi before they are presented at the cell surface. Modifications include the addition of sulfate groups at specific positions on sugar residues along the heparan sulfate (HS) chain which results in a structural heterogeneity that underpins the ability of HSPGs to bind with high affinity to many different proteins, including growth factors and their receptors. Sulf1 codes for a 6-0-endosulfatase that is present and active extracellularly, providing a further mechanism to generate structural diversity through the post-synthetic remodelling of HS. Here we use Xenopus embryos to demonstrate in vivo that Xtsulf1 plays an important role in modulating cell signaling during development. We show that while XtSulf1 can enhance the axis-inducing activity of Wnt11, XtSulf1 acts during embryogenesis to restrict BMP and FGF signaling.
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12
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Abstract
Developmental biology teachers use the example of the frog embryo to introduce young scientists to the wonders of vertebrate development, and to pose the crucial question, 'How does a ball of cells become an exquisitely patterned embryo?'. Classical embryologists also recognized the power of the amphibian model and used extirpation and explant studies to explore early embryo polarity and to define signaling centers in blastula and gastrula stage embryos. This review revisits these early stages of Xenopus development and summarizes the recent explosion of information on the intrinsic and extrinsic factors that are responsible for the first phases of embryonic patterning.
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Affiliation(s)
- Janet Heasman
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, OH 45229-3039, USA.
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13
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Abstract
How important is the contribution of mRNAs and proteins stored in the oocyte for determining the body plan of the Xenopus embryo? Here we review the current understanding of the roles of maternally supplied transcription factors, signaling molecules, and signaling regulators in establishing the ectoderm, mesoderm, and endoderm germ layers and the embryonic axes. Key essential asymmetries of VegT, Wnt11, and Ectodermin are described, as well as the complexity of maternal transcription factors that are involved in the initial expression of early zygotic genes.
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Affiliation(s)
- Janet Heasman
- Division of Developmental Biology ML7007, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA.
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14
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Berekelya LA, Ponomarev MB, Mikryukov AA, Luchinskaya NN, Belyavsky AV. Molecular Mechanisms of Germ Line Cell Determination in Animals. Mol Biol 2005. [DOI: 10.1007/s11008-005-0073-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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15
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Affiliation(s)
- Malgorzata Kloc
- Department of Molecular Genetics, M. D. Anderson Cancer Center, University of Texas, Houston, Texas 77030, USA
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Palacios IM, St Johnston D. Getting the message across: the intracellular localization of mRNAs in higher eukaryotes. Annu Rev Cell Dev Biol 2002; 17:569-614. [PMID: 11687499 DOI: 10.1146/annurev.cellbio.17.1.569] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The intracellular localization of mRNA, a common mechanism for targeting proteins to specific regions of the cell, probably occurs in most if not all polarized cell types. Many of the best characterized localized mRNAs are found in oocytes and early embryos, where they function as localized determinants that control axis formation and the development of the germline. However, mRNA localization has also been shown to play an important role in somatic cells, such as neurons, where it may be involved in learning and memory. mRNAs can be localized by a variety of mechanisms including local protection from degradation, diffusion to a localized anchor, and active transport, and we consider the evidence for each of these processes, before discussing the cis-acting elements that direct the localization of specific mRNAs and the trans-acting factors that bind them.
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Affiliation(s)
- I M Palacios
- Wellcome/CRC Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR United Kingdom.
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Sardet C, Prodon F, Dumollard R, Chang P, Chênevert J. Structure and function of the egg cortex from oogenesis through fertilization. Dev Biol 2002; 241:1-23. [PMID: 11784091 DOI: 10.1006/dbio.2001.0474] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Christian Sardet
- BioMarCell, UMR 7009 Biologie du Developpement, Villefranche sur Mer, 06230, France.
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Heasman J, Wessely O, Langland R, Craig EJ, Kessler DS. Vegetal localization of maternal mRNAs is disrupted by VegT depletion. Dev Biol 2001; 240:377-86. [PMID: 11784070 DOI: 10.1006/dbio.2001.0495] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
VegT is an essential maternal regulator of germ layer specification in Xenopus. The localization of VegT mRNA to the vegetal cortex of the oocyte during oogenesis ensures its inheritance by vegetal and not animal cells, and directs the differentiation of vegetal cells into endoderm. Similarly localized mRNAs, Vg1 and Bicaudal-C, are also inherited by vegetal cells, while germ plasm-associated mRNAs, such as Xcat2, become incorporated into vegetally derived primordial germ cells. Although mRNA localization is clearly important for tissue specification, the mechanism of mRNA anchoring to the oocyte vegetal cortex is not understood. Here, we examine the role of VegT in cortical localization. We report that depletion of VegT mRNA caused the release of Vg1 mRNA from the vegetal cortex and a reduction of Vg1 protein, without affecting the total amount of Vg1 transcript. Furthermore, we found that Bicaudal-C and Wnt11 mRNAs were also dispersed, but not degraded, by VegT depletion, while the localization of Xcat2 and Xotx1 mRNAs was unaffected. This effect was specific to the loss of VegT mRNA and not VegT protein, since a morpholino oligo against VegT, that blocked translation without degrading mRNA, did not disperse the vegetally localized mRNAs. Therefore, a subset of localized mRNAs is dependent on VegT mRNA for anchoring to the vegetal cortex, indicating a novel function for maternal VegT mRNA.
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Affiliation(s)
- J Heasman
- Division of Developmental Biology, Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
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Nakamura A, Amikura R, Hanyu K, Kobayashi S. Me31B silences translation of oocyte-localizing RNAs through the formation of cytoplasmic RNP complex duringDrosophilaoogenesis. Development 2001; 128:3233-42. [PMID: 11546740 DOI: 10.1242/dev.128.17.3233] [Citation(s) in RCA: 228] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Embryonic patterning in Drosophila is regulated by maternal factors. Many such factors become localized as mRNAs within the oocyte during oogenesis and are translated in a spatio-temporally regulated manner. These processes are controlled by trans-acting proteins, which bind to the target RNAs to form a ribonucleoprotein (RNP) complex. We report that a DEAD-box protein, Me31B, forms a cytoplasmic RNP complex with oocyte-localizing RNAs and Exuperantia, a protein involved in RNA localization. During early oogenesis, loss of Me31B causes premature translation of oocyte-localizing RNAs within nurse cells, without affecting their transport to the oocyte. These results suggest that Me31B mediates translational silencing of RNAs during their transport to the oocyte. Our data provide evidence that RNA transport and translational control are linked through the assembly of RNP complex.
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Affiliation(s)
- A Nakamura
- Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
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Kloc M, Bilinski S, Chan AP, Allen LH, Zearfoss NR, Etkin LD. RNA localization and germ cell determination in Xenopus. INTERNATIONAL REVIEW OF CYTOLOGY 2001; 203:63-91. [PMID: 11131528 DOI: 10.1016/s0074-7696(01)03004-2] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
In many organisms the proper development of the embryo depends on the asymmetrical distribution of maternal RNAs and proteins in the egg. Although the Xenopus oocyte is radially symmetrical it contains distinct populations of maternal RNAs that are localized either in the animal or vegetal pole. The process of localization of RNAs in Xenopus oocytes occurs during the long period of oocyte differentiation and growth that is accompanied by the elaboration of oocyte polarity. Some of the vegetally localized RNAs, such as Vg1, VegT, and Xwnt11, are involved in axial patterning and germ layer specification. Others, such as Xdazl and Xcat2, which are located in the germ plasm, are likely to play a role in the specification of germ cell fate. We will discuss the different aspects of RNA localization in Xenopus in the context of the differentiation of the germ cells and the development of the oocyte polarity.
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Affiliation(s)
- M Kloc
- Department of Molecular Genetics, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA
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