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Morgan GT. Isolation and Analysis of Xenopus Germinal Vesicles. Cold Spring Harb Protoc 2018; 2018:pdb.prot096958. [PMID: 29382810 DOI: 10.1101/pdb.prot096958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The giant nucleus or germinal vesicle (GV) of Xenopus oocytes provides an unusual opportunity to analyze nuclear structure and function in exquisite detail by light microscopy. Detailed here are two rapid procedures for using manually isolated GVs in combination with fluorescent reporter proteins to investigate the lampbrush chromosomes and nuclear bodies of oocytes. One procedure provides spreads of nuclear components in an unfixed and life-like, although not living, form. The other describes the isolation of intact, functional GVs directly into mineral oil offering possibilities for direct observation of nuclear dynamics.
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Affiliation(s)
- Garry T Morgan
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
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Sellés J, Penrad-Mobayed M, Guillaume C, Fuger A, Auvray L, Faklaris O, Montel F. Nuclear pore complex plasticity during developmental process as revealed by super-resolution microscopy. Sci Rep 2017; 7:14732. [PMID: 29116248 PMCID: PMC5677124 DOI: 10.1038/s41598-017-15433-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 10/26/2017] [Indexed: 02/08/2023] Open
Abstract
Nuclear Pore Complex (NPC) is of paramount importance for cellular processes since it is the unique gateway for molecular exchange through the nucleus. Unraveling the modifications of the NPC structure in response to physiological cues, also called nuclear pore plasticity, is key to the understanding of the selectivity of this molecular machinery. As a step towards this goal, we use the optical super-resolution microscopy method called direct Stochastic Optical Reconstruction Microscopy (dSTORM), to analyze oocyte development impact on the internal structure and large-scale organization of the NPC. Staining of the FG-Nups proteins and the gp210 proteins allowed us to pinpoint a decrease of the global diameter by measuring the mean diameter of the central channel and the luminal ring of the NPC via autocorrelation image processing. Moreover, by using an angular and radial density function we show that development of the Xenopus laevis oocyte is correlated with a progressive decrease of the density of NPC and an ordering on a square lattice.
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Affiliation(s)
- Julien Sellés
- Matière et Systèmes Complexes, Université Paris Diderot/CNRS (UMR 7057), 75205, Paris, Cedex 13, France
- Institut Jacques Monod, Université Paris Diderot/CNRS, UMR 7592, 15 rue Hélène Brion, 75205, Paris, CEDEX 13, France
| | - May Penrad-Mobayed
- Institut Jacques Monod, Université Paris Diderot/CNRS, UMR 7592, 15 rue Hélène Brion, 75205, Paris, CEDEX 13, France
| | - Cyndélia Guillaume
- Matière et Systèmes Complexes, Université Paris Diderot/CNRS (UMR 7057), 75205, Paris, Cedex 13, France
| | - Alica Fuger
- Matière et Systèmes Complexes, Université Paris Diderot/CNRS (UMR 7057), 75205, Paris, Cedex 13, France
| | - Loïc Auvray
- Matière et Systèmes Complexes, Université Paris Diderot/CNRS (UMR 7057), 75205, Paris, Cedex 13, France
| | - Orestis Faklaris
- ImagoSeine core facility, Institut Jacques Monod, Université Paris Diderot/CNRS, UMR 7592, 15 rue Hélène Brion, 75205, Paris, CEDEX 13, France
| | - Fabien Montel
- Matière et Systèmes Complexes, Université Paris Diderot/CNRS (UMR 7057), 75205, Paris, Cedex 13, France.
- Univ Lyon, Ens de Lyon, Univ Claude Bernard, CNRS, Laboratoire de Physique, F-69342, Lyon, France.
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How does chromatin package DNA within nucleus and regulate gene expression? Int J Biol Macromol 2017; 101:862-881. [PMID: 28366861 DOI: 10.1016/j.ijbiomac.2017.03.165] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 01/26/2023]
Abstract
The human body is made up of 60 trillion cells, each cell containing 2 millions of genomic DNA in its nucleus. How is this genomic deoxyribonucleic acid [DNA] organised into nuclei? Around 1880, W. Flemming discovered a nuclear substance that was clearly visible on staining under primitive light microscopes and named it 'chromatin'; this is now thought to be the basic unit of genomic DNA organization. Since long before DNA was known to carry genetic information, chromatin has fascinated biologists. DNA has a negatively charged phosphate backbone that produces electrostatic repulsion between adjacent DNA regions, making it difficult for DNA to fold upon itself. In this article, we will try to shed light on how does chromatin package DNA within nucleus and regulate gene expression?
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Ladomery M, Sommerville J. The Scd6/Lsm14 protein xRAPB has properties different from RAP55 in selecting mRNA for early translation or intracellular distribution in Xenopus oocytes. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:1363-73. [PMID: 26455898 DOI: 10.1016/j.bbagrm.2015.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 10/03/2015] [Accepted: 10/05/2015] [Indexed: 11/17/2022]
Abstract
Oocytes accumulate mRNAs in the form of maternal ribonucleoprotein (RNP) particles, the protein components of which determine the location and stability of individual mRNAs prior to translation. Scd6/Lsm14 proteins, typified by RAP55, function in a wide range of eukaryotes in repressing translation and relocating mRNPs to processing bodies and stress granules. In Xenopus laevis, the RAP55 orthologue xRAPA fulfils these functions. Here we describe the properties of a variant of xRAPA, xRAPB, which is a member of the Lsm14B group. xRAPB differs from xRAPA in various respects: it is expressed at high concentration earlier in oogenesis; it interacts specifically with the DDX6 helicase Xp54; it is detected in polysomes and stalled translation initiation complexes; its over-expression leads to selective binding to translatable mRNA species without evidence of translation repression or mRNA degradation. Since both Xp54 and xRAPA are repressors of translation, activation appears to be effected through targeting of xRAPB/Xp54.
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Affiliation(s)
- Michael Ladomery
- Biomedical Sciences Research Complex, Biomolecular Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9TS, UK
| | - John Sommerville
- Biomedical Sciences Research Complex, Biomolecular Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9TS, UK.
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Abstract
The oocytes of the African clawed frog (Xenopus laevis) comprise one of the most widely used membrane protein expression systems. While frequently used for studies of transporters and ion channels, the application of this system to the study of mechanosensitive ion channels has been overlooked, perhaps due to a relative abundance of native expression systems. Recent advances, however, have illustrated the advantages of the oocyte system for studying plant and bacterial mechanosensitive channels. Here we describe in detail the methods used for heterologous expression and characterization of bacterial and plant mechanosensitive channels in Xenopus oocytes.
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Affiliation(s)
- Grigory Maksaev
- Department of Biology, Washington University in Saint Louis, One Brookings Drive, Mail Code 1137, Saint Louis, MO, 63130, USA
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Precocious detection on amphibian oocyte lampbrush chromosomes of subtle changes in the cellular localisation of the Ro52 protein induced by in vitro culture. Chromosome Res 2013; 20:1033-44. [PMID: 23149575 DOI: 10.1007/s10577-012-9325-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Subterminal lampbrush loops of one of the 12 bivalents of the oocyte karyotype of Pleurodeles waltl (Amphibian, Urodele) underwent prominent morphological changes upon in vitro culture. These loops exhibited a fine ribonucleoprotein (RNP) granular matrix, which evolved during culture into huge structures that we have named 'chaussons' (slippers). This phenomenon involved progressive accumulation of proteins in the RNP matrix without protein neosynthesis. One of these proteins, which translocated into the nucleus during the culture, was identified as a homolog of the human Ro52 E3 ubiquitin ligase. RNA polymerase III was also found to accumulate on the same loops. These results suggest that the subterminal loops of bivalent XII act as a storage site for the components of a nuclear machinery involved in the quality control of RNA synthesis and maturation in response to cellular stress. They also emphasise the considerable value of the lampbrush chromosome system for a direct visualisation of modifications in gene expression and open the question of a nuclear accumulation of Ro52 in human or animal oocytes cultured in vitro for assisted reproductive technologies (ART).
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Krasikova A, Khodyuchenko T, Maslova A, Vasilevskaya E. Three-dimensional organisation of RNA-processing machinery in avian growing oocyte nucleus. Chromosome Res 2012; 20:979-94. [DOI: 10.1007/s10577-012-9327-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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