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Sherrard RM, Morellini N, Jourdan N, El-Esawi M, Arthaut LD, Niessner C, Rouyer F, Klarsfeld A, Doulazmi M, Witczak J, d’Harlingue A, Mariani J, Mclure I, Martino CF, Ahmad M. Low-intensity electromagnetic fields induce human cryptochrome to modulate intracellular reactive oxygen species. PLoS Biol 2018; 16:e2006229. [PMID: 30278045 PMCID: PMC6168118 DOI: 10.1371/journal.pbio.2006229] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/29/2018] [Indexed: 12/11/2022] Open
Abstract
Exposure to man-made electromagnetic fields (EMFs), which increasingly pollute our environment, have consequences for human health about which there is continuing ignorance and debate. Whereas there is considerable ongoing concern about their harmful effects, magnetic fields are at the same time being applied as therapeutic tools in regenerative medicine, oncology, orthopedics, and neurology. This paradox cannot be resolved until the cellular mechanisms underlying such effects are identified. Here, we show by biochemical and imaging experiments that exposure of mammalian cells to weak pulsed electromagnetic fields (PEMFs) stimulates rapid accumulation of reactive oxygen species (ROS), a potentially toxic metabolite with multiple roles in stress response and cellular ageing. Following exposure to PEMF, cell growth is slowed, and ROS-responsive genes are induced. These effects require the presence of cryptochrome, a putative magnetosensor that synthesizes ROS. We conclude that modulation of intracellular ROS via cryptochromes represents a general response to weak EMFs, which can account for either therapeutic or pathological effects depending on exposure. Clinically, our findings provide a rationale to optimize low field magnetic stimulation for novel therapeutic applications while warning against the possibility of harmful synergistic effects with environmental agents that further increase intracellular ROS. Repetitive low-intensity magnetic stimulation has been used in the treatment of disease for over 50 years. Associated benefits have included alleviation of depression, memory loss, and symptoms of Parkinson disease, as well as accelerated bone and wound healing and the treatment of certain cancers, independently of surgery or drugs. However, the cellular mechanisms underlying these effects remain unclear. Here, we demonstrate that repetitive magnetic field exposure in human cells stimulates production of biological stress response chemicals known as reactive oxygen species (ROS). At moderate doses, we find that reactive oxygen actively stimulates cellular repair and stress response pathways, which might account for the observed therapeutic effects to repetitive magnetic stimulation. We further show that this response requires the function of a well-characterized, evolutionarily conserved flavoprotein receptor known as cryptochrome, which has been implicated in magnetic sensing in organisms ranging from plants to flies, including migratory birds. We conclude that exposure to weak magnetic fields induces the production of ROS in human cells and that this process requires the presence of the cryptochrome receptor.
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Affiliation(s)
- Rachel M. Sherrard
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Team Repairing Neural Networks, Paris, France
| | - Natalie Morellini
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Team Repairing Neural Networks, Paris, France
| | - Nathalie Jourdan
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
| | - Mohamed El-Esawi
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
- Botany Department, Faculty of Science, Tanta University, Tanta, Egypt
| | - Louis-David Arthaut
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
| | - Christine Niessner
- Department of Earth and Environmental Sciences, Ludwig-Maximillians-Universität Munich, Theresienstraße, Munich, Germany
| | - Francois Rouyer
- Institut des Neurosciences Paris-Saclay, Université Paris Sud, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Andre Klarsfeld
- Brain Plasticity Unit, UMR 8249 (ESPCI Paris/CNRS), PSL Research University, Paris, France
| | - Mohamed Doulazmi
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Team Repairing Neural Networks, Paris, France
| | - Jacques Witczak
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
| | - Alain d’Harlingue
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
| | - Jean Mariani
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Team Repairing Neural Networks, Paris, France
| | - Ian Mclure
- Department of Biomedical Engineering, Florida Institute of Technology, Melbourne, Florida, United States of America
| | - Carlos F. Martino
- Department of Biomedical Engineering, Florida Institute of Technology, Melbourne, Florida, United States of America
| | - Margaret Ahmad
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
- Xavier University, Cincinnati, Ohio, United States of America
- * E-mail:
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2
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Zhang X, Lorenceau E, Basset P, Bourouina T, Rouyer F, Goyon J, Coussot P. Wall Slip of Soft-Jammed Systems: A Generic Simple Shear Process. Phys Rev Lett 2017; 119:208004. [PMID: 29219383 DOI: 10.1103/physrevlett.119.208004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Indexed: 06/07/2023]
Abstract
From well-controlled long creep tests, we show that the residual apparent yield stress observed with soft-jammed systems along smooth surfaces is an artifact due to edge effects. By removing these effects, we can determine the stress solely associated with steady-state wall slip below the material yield stress. This stress is found to vary linearly with the slip velocity for a wide range of materials whatever the structure, the interaction types between the elements and with the wall, and the concentration. Thus, wall slip results from the laminar flow of some given free liquid volume remaining between the (rough) jammed structure formed by the elements and the smooth wall. This phenomenon may be described by the simple shear flow in a Newtonian liquid layer of uniform thickness. For various systems, this equivalent thickness varies in a narrow range (35±15 nm).
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Affiliation(s)
- X Zhang
- Université Paris-Est, Laboratoire Navier (ENPC-IFSTTAR-CNRS), 2 Allée Kepler, 77420 Champs sur Marne, France
| | - E Lorenceau
- Université Grenoble-Alpes, CNRS, LIPhy, 38000 Grenoble, France
| | - P Basset
- Université Paris-Est, ESYCOM EA 2552, ESIEE Paris-CNAM-UPEM, 5 Boulevard Descartes, 77420 Champs sur Marne, France
| | - T Bourouina
- Université Paris-Est, ESYCOM EA 2552, ESIEE Paris-CNAM-UPEM, 5 Boulevard Descartes, 77420 Champs sur Marne, France
| | - F Rouyer
- Université Paris-Est, Laboratoire Navier (ENPC-IFSTTAR-CNRS), 2 Allée Kepler, 77420 Champs sur Marne, France
| | - J Goyon
- Université Paris-Est, Laboratoire Navier (ENPC-IFSTTAR-CNRS), 2 Allée Kepler, 77420 Champs sur Marne, France
| | - P Coussot
- Université Paris-Est, Laboratoire Navier (ENPC-IFSTTAR-CNRS), 2 Allée Kepler, 77420 Champs sur Marne, France
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3
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Abstract
To what extent are aqueous foams prone to clogging? Foam permeability is measured as a function of particulate loading (trapped hydrophilic particles) under conditions where the particle to bubble size ratio is allowed to increase when the number of particles per bubble is fixed. In addition to experiments performed on the foam scale, we investigated experimentally and numerically the hydrodynamic resistance of a single foam node loaded with one particle. It is shown that, with respect to solid porous media, aqueous foams clog more efficiently due to two reasons: (i) the deformation of interfaces allows for larger particles to be incorporated within the interstitial network and (ii) the interfacial mobility contributes to lowering of the reduced permeability.
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Affiliation(s)
- F Rouyer
- Université Paris Est, Laboratoire Navier, UMR 8205 CNRS - École des Ponts ParisTech - IFSTTAR 5 bd Descartes, 77454 Marne-la-Vallée Cedex 2, France
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Wiel E, Rouyer F. [From E-FAST to clinical echography]. Ann Fr Anesth Reanim 2014; 33:149-150. [PMID: 24613248 DOI: 10.1016/j.annfar.2014.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- E Wiel
- Pôle de l'urgence, Samu du Nord, CHRU de Lille, 5, avenue Oscar-Lambret, 59037 Lille cedex, France; EA 2694, laboratoire de santé publique, faculté d'ingénierie et de management de la santé, université Lille-Nord-de-France, 42, rue Ambroise-Paré, 59010 Loos, France.
| | - F Rouyer
- Unité de soins intensifs-surveillance continue, centre hospitalier de Seclin, rue d'Apolda, 59113 Seclin, France
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Assez N, Lemanski-Brulin C, Aboukais W, Sebilleau Q, Adriansen C, Rouyer F, Wiel E, Goldstein P. Défis de la prise en charge du syndrome coronaire aigu en pré-hospitalier. Archives of Cardiovascular Diseases Supplements 2012. [DOI: 10.1016/s1878-6480(12)70835-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Vieira J, Jones AR, Danon A, Sakuma M, Hoang N, Robles D, Tait S, Heyes DJ, Picot M, Yoshii T, Helfrich-Förster C, Soubigou G, Coppee JY, Klarsfeld A, Rouyer F, Scrutton NS, Ahmad M. Human cryptochrome-1 confers light independent biological activity in transgenic Drosophila correlated with flavin radical stability. PLoS One 2012; 7:e31867. [PMID: 22427812 PMCID: PMC3299647 DOI: 10.1371/journal.pone.0031867] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 01/13/2012] [Indexed: 01/11/2023] Open
Abstract
Cryptochromes are conserved flavoprotein receptors found throughout the biological kingdom with diversified roles in plant development and entrainment of the circadian clock in animals. Light perception is proposed to occur through flavin radical formation that correlates with biological activity in vivo in both plants and Drosophila. By contrast, mammalian (Type II) cryptochromes regulate the circadian clock independently of light, raising the fundamental question of whether mammalian cryptochromes have evolved entirely distinct signaling mechanisms. Here we show by developmental and transcriptome analysis that Homo sapiens cryptochrome--1 (HsCRY1) confers biological activity in transgenic expressing Drosophila in darkness, that can in some cases be further stimulated by light. In contrast to all other cryptochromes, purified recombinant HsCRY1 protein was stably isolated in the anionic radical flavin state, containing only a small proportion of oxidized flavin which could be reduced by illumination. We conclude that animal Type I and Type II cryptochromes may both have signaling mechanisms involving formation of a flavin radical signaling state, and that light independent activity of Type II cryptochromes is a consequence of dark accumulation of this redox form in vivo rather than of a fundamental difference in signaling mechanism.
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Affiliation(s)
| | - Alex R. Jones
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | | | - Michiyo Sakuma
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | | | | | - Shirley Tait
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Derren J. Heyes
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Marie Picot
- Institut de Neurobiologie Alfred Fessard, CNRS UPR 2216 (NGI), Gif-sur-Yvette, France
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | | | - Guillaume Soubigou
- Institut Pasteur, Transcriptome and Epigenome Platform, Genomes and Genetics Department, Paris, France
| | - Jean-Yves Coppee
- Institut Pasteur, Transcriptome and Epigenome Platform, Genomes and Genetics Department, Paris, France
| | - André Klarsfeld
- Institut de Neurobiologie Alfred Fessard, CNRS UPR 2216 (NGI), Gif-sur-Yvette, France
| | - Francois Rouyer
- Institut de Neurobiologie Alfred Fessard, CNRS UPR 2216 (NGI), Gif-sur-Yvette, France
| | - Nigel S. Scrutton
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Margaret Ahmad
- Université Paris VI, Paris, France
- Penn State University, Media, Pennsylvania, United States of America
- * E-mail:
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Rouyer F, Facon A, Adriansen C, Assez N, Auffray JL, Bauchart JJ, Ennezat PV, Asseman P, Wiel E, Goldstein P. 245 Improvement of ST Elevation Myocardial Infarction (STEMI) management. BMJ Qual Saf 2010. [DOI: 10.1136/qshc.2010.041624.58] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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9
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Johard HA, Yoishii T, Dircksen H, Cusumano P, Rouyer F, Helfrich-Förster C, Nässel DR. Peptidergic clock neurons inDrosophila: Ion transport peptide and short neuropeptide F in subsets of dorsal and ventral lateral neurons. J Comp Neurol 2009; 516:59-73. [DOI: 10.1002/cne.22099] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Pitois O, Louvet N, Rouyer F. Recirculation model for liquid flow in foam channels. Eur Phys J E Soft Matter 2009; 30:27-35. [PMID: 19756794 DOI: 10.1140/epje/i2009-10502-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 06/19/2009] [Accepted: 07/27/2009] [Indexed: 05/28/2023]
Abstract
Although extensively studied in the past, drainage of aqueous foams still offers major unaddressed issues. Among them, the behaviour of foam films during drainage has great significance as the thickness of the films is known to control the Ostwald ripening in foams, which in turn impacts liquid drainage. We propose a model relating the films' behavior to the liquid flow in foam channels. It is assumed that Marangoni-driven recirculation counterflows take place in the transitional region between the foam channel and the adjoining films, and the Gibbs elasticity is therefore introduced as a relevant parameter. The velocity of these counterflows is found to be proportional to the liquid velocity in the channel. The resulting channel permeability is determined and it is shown that Marangoni stresses do not contribute to rigidify the channel's surfaces, in strong contrast with the drainage of horizontal thin liquid films. New experimental data are provided and support the proposed model.
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Affiliation(s)
- O Pitois
- Laboratoire de Physique des Matériaux Divisés et des Interfaces, Université Paris-Est, UMR CNRS 8108, 5 bvd Descartes, 77454 Marne la Vallée Cedex 2, France.
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11
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Rieger D, Wülbeck C, Rouyer F, Helfrich-Förster C. Period Gene Expression in Four Neurons Is Sufficient for Rhythmic Activity of Drosophila melanogaster under Dim Light Conditions. J Biol Rhythms 2009; 24:271-82. [DOI: 10.1177/0748730409338508] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The clock gene expressing lateral neurons (LN) is crucial for Drosophila 's rhythmic locomotor activity under constant conditions. Among the LN, the PDF expressing small ventral lateral neurons (s-LNv) are thought to control the morning activity of the fly (M oscillators) and to drive rhythmic activity under constant darkness. In contrast, a 5th PDF-negative s-LN v and the dorsal lateral neurons (LNd) appeared to control the fly's evening activity (E oscillators) and to drive rhythmic activity under constant light. Here, the authors restricted period gene expression to 4 LN—the 5th s-LNv and 3 LNd— that are all thought to belong to the E oscillators and tested them in low light conditions. Interestingly, such flies showed rather normal bimodal activity patterns under light moonlight and constant moonlight conditions, except that the phase of M and E peaks was different. This suggests that these 4 neurons behave as ″M″ and ″E″ cells in these conditions. Indeed, they found by PER and TIM immunohistochemistry that 2 LNd advanced their phase upon moonlight as predicted for M oscillators, whereas the 5th s-LNv and 1 LNd delayed their activity upon moonlight as predicted for E oscillators. Their results suggest that the M or E characteristic of clock neurons is rather flexible. M and E oscillator function may not be restricted to certain anatomically defined groups of clock neurons but instead depends on the environmental conditions.
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Affiliation(s)
- Dirk Rieger
- Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Corinna Wülbeck
- Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Francois Rouyer
- Institut de Neurobiologie Alfred Fessard, CNRS UPR2216, Gif-sur-Yvette, France
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12
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Louvet N, Rouyer F, Pitois O. Ripening of a draining foam bubble. J Colloid Interface Sci 2009; 334:82-6. [DOI: 10.1016/j.jcis.2009.02.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2009] [Revised: 02/17/2009] [Accepted: 02/19/2009] [Indexed: 10/21/2022]
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13
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Lorenceau E, Louvet N, Rouyer F, Pitois O. Permeability of aqueous foams. Eur Phys J E Soft Matter 2009; 28:293-304. [PMID: 19190946 DOI: 10.1140/epje/i2008-10411-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 10/20/2008] [Accepted: 12/19/2008] [Indexed: 05/27/2023]
Abstract
We perform forced-drainage experiments in aqueous foams and compare the results with data available in the literature. We show that all the data can be accurately compared together if the dimensionless permeability of the foam is plotted as a function of liquid fraction. Using this set of coordinates highlights the fact that a large part of the published experimental results corresponds to relatively wet foams (epsilon approximately 0.1). Yet, most of the foam drainage models are based on geometrical considerations only valid for dry foams. We therefore discuss the range of validity of the different models in the literature and their comparison to experimental data. We propose extensions of these models considering the geometry of foam in the relatively wet-foam limit. We eventually show that if the foam geometry is correctly described, forced drainage experiments can be understood using a unique parameter --the Boussinesq number.
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Affiliation(s)
- E Lorenceau
- Université Paris-Est, Laboratoire de Physique des Matériaux Divisés et des Interfaces, UMR 8108 du CNRS, Marne-la-Vallée, France.
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14
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Abstract
Liquid foams were recognized early to be porous materials, as liquid flowed between the gas bubbles. Drainage theories have been established, and foam permeability has been modeled from the microscopic description of the equivalent pores geometry, emphasizing similarities with their solid counterparts. But to what extent can the theoretical work devoted to the permeability of solid porous materials be useful to liquid foams? In this article, the applicability of the Carman-Kozeny model on foam is investigated. We performed measurements of the permeability of foams with nonmobile surfactants, and we show that, in introducing an equivalent specific surface area for the foam, the model accurately describes the experimental data over two orders of magnitude for the foam liquid fraction, without any additional parameters. Finally, it is shown that this model includes the previous permeability models derived for foams in the dry foams limit.
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Affiliation(s)
- O Pitois
- Universite Paris-Est, Laboratoire de Physique des Materiaux Divises et des Interfaces, UMR CNRS 8108, 5 bvd Descartes, 77454 Marne la Vallee Cedex 2, France.
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16
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Pitois O, Louvet N, Lorenceau E, Rouyer F. Node contribution to the permeability of liquid foams. J Colloid Interface Sci 2008; 322:675-7. [DOI: 10.1016/j.jcis.2008.04.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 04/14/2008] [Accepted: 04/15/2008] [Indexed: 10/22/2022]
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Helfrich-Förster C, Yoshii T, Wülbeck C, Grieshaber E, Rieger D, Bachleitner W, Cusumano P, Rouyer F. The lateral and dorsal neurons of Drosophila melanogaster: new insights about their morphology and function. Cold Spring Harb Symp Quant Biol 2007; 72:517-525. [PMID: 18419311 DOI: 10.1101/sqb.2007.72.063] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This chapter summarizes our present knowledge about the master clock of the fruit fly at the neuronal level. The clock is organized in distinct groups of interconnected pacemaker neurons with different functions. All of these neurons appear to communicate with one another in order to produce the species-specific activity rhythm, which is organized in morning (M) and evening (E) activity bouts. These two activity components are differentially influenced by distinct groups of pacemaker neurons reminiscent of the Pittendrigh-Daan dual oscillator model. In the original work (Grima et al. 2004; Stoleru et al. 2004), the ventrolateral (LN(v)) and dorsolateral (LN(d)) plus some dorsal groups (DN) of clock neurons have been defined as M and E cells, respectively. We further specify that the clock neurons belong to the M and E oscillators and define a more complex picture of the Drosophila brain clock.
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Affiliation(s)
- C Helfrich-Förster
- University of Regensburg, Institute of Zoology, 93040 Regensburg, Germany
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18
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Easwar K, Rouyer F, Menon N. Speeding to a stop: the finite-time singularity of a spinning disk. Phys Rev E Stat Nonlin Soft Matter Phys 2002; 66:045102. [PMID: 12443243 DOI: 10.1103/physreve.66.045102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2001] [Revised: 08/09/2002] [Indexed: 05/24/2023]
Abstract
The final stages of a coin spinning on a flat surface have recently been proposed [H.K. Moffatt, Nature (London) 404, 833 (2000)] as an example of a finite-time singularity, wherein the precession rate of the symmetry axis of the coin diverges as it comes to a stop. We report measurements by high-speed video imaging of the rolling motion of disks and rings on a variety of surfaces. We find that the precession rate, Omega, diverges as a power law in time: Omega(t) proportional, variant (t-t(o))(-1/n), where t(o) is the instant the motion ceases. The exponent n varies between 2.7 and 3.2 under different experimental conditions. The value of n, as well as the systematic dependence of precession rate on coefficients of friction, establishes that the primary mechanism of energy dissipation is rolling friction rather than air drag, as previously suggested.
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Affiliation(s)
- K Easwar
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA
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Blanchardon E, Grima B, Klarsfeld A, Chélot E, Hardin PE, Préat T, Rouyer F. Defining the role of Drosophila lateral neurons in the control of circadian rhythms in motor activity and eclosion by targeted genetic ablation and PERIOD protein overexpression. Eur J Neurosci 2001; 13:871-88. [PMID: 11264660 DOI: 10.1046/j.0953-816x.2000.01450.x] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ventral lateral neurons (LNvs) of the Drosophila brain that express the period (per) and pigment dispersing factor (pdf) genes play a major role in the control of circadian activity rhythms. A new P-gal4 enhancer trap line is described that is mostly expressed in the LNvs This P-gal4 line was used to ablate the LNvs by using the pro-apoptosis gene bax, to stop PER protein oscillations by overexpressing per and to block synaptic transmission with the tetanus toxin light chain (TeTxLC). Genetic ablation of these clock cells leads to the loss of robust 24-h activity rhythms and reveals a phase advance in light-dark conditions as well as a weak short-period rhythm in constant darkness. This behavioural phenotype is similar to that described for disconnected1 (disco1) mutants, in which we show that the majority of the individuals have a reduced number of dorsally projecting lateral neurons which, however, fail to express PER. In both LNv-ablated and disco1 flies, PER cycles in the so-called dorsal neurons (DNs) of the superior protocerebrum, suggesting that the weak short-period rhythm could stem from these PDF-negative cells. The overexpression of per in LNs suppresses PER protein oscillations and leads to the disruption of both activity and eclosion rhythms, indicating that PER cycling in these cells is required for both of these rhythmic behaviours. Interestingly, flies overexpressing PER in the LNs do not show any weak short-period rhythms, although PER cycles in at least a fraction of the DNs, suggesting a dominant role of the LNs on the behavioural rhythms. Expression of TeTxLC in the LNvs does not impair activity rhythms, which indicates that the PDF-expressing neurons do not use synaptobrevin-dependent transmission to control these rhythms.
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Affiliation(s)
- E Blanchardon
- Institut de Neurobiologie Alfred Fessard, CNRS UPR 2216 (NGI), Av. de la terrasse, 91198 Gif-sur-Yvette, France
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Abstract
We have measured the spectrum of velocity fluctuations in a granular system confined to a vertical plane and driven into a homogeneous, steady state by strong vertical vibration. The distribution of horizontal velocities is not Maxwell-Boltzmann and is given by P(v) = Cexp[-beta(|v|/sigma)(alpha)] where alpha = 1.55+/-0.1 at all frequencies and amplitudes investigated, and also for varying boundary conditions. The deviation from Maxwell-Boltzmann statistics occurs in the absence of spatial clustering and does not result from an inhomogeneous average over regions of varying local density. Surprisingly, P(v) has the same shape over a wide range of densities.
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Affiliation(s)
- F Rouyer
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003-3720, USA
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21
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Fortin G, del Toro ED, Abadie V, Guimarães L, Foutz AS, Denavit-Saubié M, Rouyer F, Champagnat J. Genetic and developmental models for the neural control of breathing in vertebrates. Respir Physiol 2000; 122:247-57. [PMID: 10967348 DOI: 10.1016/s0034-5687(00)00163-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present paper reviews some of the possible mechanisms that may link gene function in the brainstem and breathing patterns in vertebrates. On one hand, adaptation and acclimatisation of mature breathing to environmental constraints such as hypoxia, involves complex regulation of the gene expression in precise cardiorespiratory sites of the brainstem. On the other hand, targeted inactivation of different genes suggests that postnatal respiratory variables at rest depend on genes controlling the prenatal development of the brainstem. During embryogenesis, neurotrophins (gdnf, bdnf) regulate the survival of specific cellular populations composing the respiratory neuronal network. The expression of developmental genes such as Hox and Krox-20 initiates hindbrain segmentation, the earliest sign of regionalisation in the brainstem. As shown in the chick embryo, segmental specifications allow the establishment of an active embryonic rhythmic network and later insertion of specific neuronal circuits increasing the primordial rhythm frequency to near mature values.
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Affiliation(s)
- G Fortin
- U.P.R. 2216, Neurobiologie Génétique et Intégrative, C.N.R.S., Avenue de la Terrasse, Bâtiment 33, 91198, Gif-sur-Yvette, France
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22
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Abstract
The pervasive occurrence of circadian clocks throughout the living world underlines their adaptive value. Nonetheless, there is surprisingly little evidence for a negative impact, on any animal species, of a constant discrepancy between the environmental and endogenous periods. Male Drosophila melanogaster per mutants with altered circadian periods were compared to the wild type in two different LD schedules. Life span was used as a global index of physiological adaptation. The life span of the mutants was significantly reduced by up to 15% for the flies whose period differs most from that of the wild type. A reduction was observed even when flies were kept in an LD schedule fitting a mutant period. The LD schedule made no significant difference on its own, but the authors found evidence for an interaction between genotype and LD schedule in determining life span. These results are consistent with the importance of the circadian clock in maintaining internal temporal order independent of environmental cycles. Nonetheless, a large difference between the environmental and endogenous periods has a measurable impact.
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Affiliation(s)
- A Klarsfeld
- Institut Alfred Fessard, CNRS UPR 2212, Gif-sur-Yvette, France
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23
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Rouyer F. Chez la drosophile, les horloges circadiennes ont leurs propres yeux. Med Sci (Paris) 1998. [DOI: 10.4267/10608/1060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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24
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Abstract
The expression of the period (per) gene of Drosophila melanogaster has been studied by in situ hybridization in the adult's head, where it is required for the fly to exhibit behavioral circadian rhythms. We have used non-radioactive in situ hybridization to obtain a high sensitivity and specificity on head sections, with single cell resolution. Consistent with previous per protein- or per reporter gene-expression, per-expressing cells were detected in the optic lobes and the central brain, as well as in the head sensory organs: eyes, ocelli, maxillary palps and proboscis. In the brain and the eyes, circadian fluctuations of the per mRNA abundance were observed in different per expressing cells.
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Affiliation(s)
- M Rachidi
- Dépt. de Biologie Moléculaire, Institut Pasteur, Paris, France
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25
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Abstract
Circadian rhythms of locomotor activity and eclosion in Drosophila depend upon the reciprocal autoregulation of the period (per) and timeless (tim) genes. As part of this regulatory loop, per and tim mRNA levels oscillate in a circadian fashion. Other cycling transcripts may participate in this central pacemaker mechanism or represent outputs of the clock. In this paper, we report the isolation of Crg-1, a new circadianly regulated gene. Like per and tim transcript levels, Crg-1 transcript levels oscillate with a 24 h period in light:dark (LD) conditions, with a maximal abundance at the beginning of the night. These oscillations persist in complete darkness and depend upon per and tim proteins. The putative CRG-1 proteins show some sequence similarity with the DNA-binding domain of the HNF3/fork head family of transcription factors. In the adult head, in situ hybridization analysis reveals that per and Crg-1 have similar expression patterns in the eyes and optic lobes.
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Affiliation(s)
- F Rouyer
- HHMI and Department of Biology, Brandeis University, Waltham, MA 02254, USA.
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26
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Pikielny CW, Hasan G, Rouyer F, Rosbash M. Members of a family of Drosophila putative odorant-binding proteins are expressed in different subsets of olfactory hairs. Neuron 1994; 12:35-49. [PMID: 7545907 DOI: 10.1016/0896-6273(94)90150-3] [Citation(s) in RCA: 250] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A polymerase chain reaction-based method was used to generate a Drosophila melanogaster antennal cDNA library from which head cDNAs were subtracted. We identified five cDNAs that code for antennal proteins containing six cysteines in a conserved pattern shared with known moth antennal proteins, including pheromone-binding proteins. Another cDNA codes for a protein related to vertebrate brain proteins that bind hydrophobic ligands. In all, we describe seven antennal proteins which contain potential signal peptides, suggesting that, like pheromone-binding proteins, they may be secreted in the lumen of olfactory hairs. The expression patterns of these putative odorant-binding proteins define at least four different subsets of olfactory hairs and suggest that the Drosophila olfactory apparatus is functionally segregated.
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Affiliation(s)
- C W Pikielny
- Howard Hughes Institute, Brandeis University, Waltham, Massachusetts 02254
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27
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Petit C, Levilliers J, Rouyer F, Simmler MC, Herouin E, Weissenbach J. Isolation of sequences from Xp22.3 and deletion mapping using sex chromosome rearrangements from human X-Y interchange sex reversals. Genomics 1990; 6:651-8. [PMID: 2341154 DOI: 10.1016/0888-7543(90)90500-t] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A repeated DNA element (STIR) interspersed in Xp22.3 and on the Y chromosome has been used as a tag to isolate seven single-copy probes from the human sex chromosomes. The seven probes detect X-specific loci located in Xp22.3. Using a panel of X-chromosomal deletions from X-Y interchange sex reversals (XX males and XY females), these X-specific loci and some additional ones were mapped to four contiguous intervals of Xp22.3, proximal to the pseudoautosomal region and distal to STS. The construction of this deletion map of the terminal part of the human X chromosome can serve as a starting point for a long-range physical map of Xp22.3 and for a more accurate mapping of genetic diseases located in Xp22.3.
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Affiliation(s)
- C Petit
- Unité de Recombinaison et Expression Génétique, INSERM U 163, CNRS UA 271, Institut Pasteur, Paris, France
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28
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Affiliation(s)
- F Rouyer
- Unité de recombinaison et d'expression génétique, INSERM U163, CNRS LA271, Institut Pasteur, Paris, France
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29
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Rouyer F, de la Chapelle A, Weissenbach J. A polymorphic DNA sequence from the terminal part of chromosome 12q [D12S37]. Nucleic Acids Res 1990; 18:1664. [PMID: 1691488 PMCID: PMC330573 DOI: 10.1093/nar/18.6.1664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- F Rouyer
- Unité de recombinaison et d'expression génétique, INSERM U163, CNRS LA271, Institut Pasteur, Paris, France
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30
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Rouyer F, de la Chapelle A, Weissenbach J. A polymorphic DNA sequence from the terminal part of chromosome 5p [D5S109]. Nucleic Acids Res 1990; 18:1663. [PMID: 1970176 PMCID: PMC330571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- F Rouyer
- Unité de recombinaíson et d'expression, génétique, INSERM U163, CNRS LA271, Institut Paris, France
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31
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Affiliation(s)
- F Rouyer
- Unité de recombinaison et d'expression, génétique, INSERM U163, CNRS LA271, Institut Pasteur, Paris, France
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32
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Rouyer F, de la Chapelle A, Weissenbach J. A polymorphic DNA sequence from the terminal part of chromosome 21q [D21S154]. Nucleic Acids Res 1990; 18:1663. [PMID: 1970175 PMCID: PMC330572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- F Rouyer
- Unité de recombinaison et d'expression génétique, INSERM U163, CNRS LA271, Institut Pasteur, Paris, France
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33
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Abstract
A family of DNA loci (DNF28) from the pseudoautosomal region of the human sex chromosomes is characterized by a repeated element (STIR: subtelomeric interspersed repeat) which detects homologous sequences in the telomeric regions of human autosomes by in situ hybridization. Several STIR elements from both the pseudoautosomal region and terminal parts of autosomes were cloned and sequenced. A conserved 350 bp sequence and some characteristic structural differences between the autosomal and pseudoautosomal STIRs were observed. Screening of the DNA sequence databases with a consensus sequence revealed the presence of STIRs in several human loci localized in the terminal parts of different chromosomes. We mapped single copy probes flanking the cloned autosomal STIRs to the subtelomeric parts of six different chromosomes by in situ hybridization and genetic linkage analysis. The linkage data show a greatly increased recombination frequency in the subtelomeric regions of the chromosomes, especially in male meiosis. The STIR elements, specifically located in subtelomeric regions, could play a role in the peculiar recombination properties of these chromosomal regions, e.g. by promoting initiation of pairing at meiosis.
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Affiliation(s)
- F Rouyer
- Unité de Recombinaison et Expression Génétique, INSERM U163, CNRS UA271, Institut Pasteur, Paris, France
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34
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Abstract
Human XX maleness is often due to the presence of Y-specific DNA, resulting from abnormal interchange of terminal parts of the short arms of the X and Y chromosomes. In an XX male, a rearrangement is observed at locus DXYS5, the most proximal Yp locus detected in this patient. Cloning and analysis of the rearranged DNA fragment revealed pseudoautosomal sequences located beyond the breakpoint. We propose that this XX male arose by abnormal crossing over between DXYS5 on the Y chromosome and a pseudoautosomal locus on the X chromosome during paternal meiosis. Sequence analysis of the junction shows that homologous recombination occurred between two Alu sequences from these otherwise nonhomologous regions. The site of recombination is localized to the putative transcription promoter region of the Alu sequences.
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Affiliation(s)
- F Rouyer
- Unité de Recombinaison et Expression Génétique, INSERM U163, CNRS UA 271, Institut Pasteur, Paris, France
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35
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Simmler MC, Johnsson C, Petit C, Rouyer F, Vergnaud G, Weissenbach J. Two highly polymorphic minisatellites from the pseudoautosomal region of the human sex chromosomes. EMBO J 1987; 6:963-9. [PMID: 3595565 PMCID: PMC553490 DOI: 10.1002/j.1460-2075.1987.tb04846.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two pseudoautosomal loci DXYS15 and DXYS17 from the pairing region of the human sex chromosomes display a high variability with at least eight alleles each. The structural elements responsible for the polymorphisms have been isolated and sequenced. In both cases the variations result from DNA rearrangements occurring in tandemly repeated sequences (minisatellites) of 21-29 nucleotides for DXYS15 and 28-33 nucleotides for DXYS17. At reduced stringency, the DXYS15 minisatellite detects other hypervariable sequences located in other parts of the genome and hence represents a new family of minisatellites. In contrast to most other known hypervariable families, the DXYS15 hypervariable sequence displays a very high AT content.
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36
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Vergnaud G, Page DC, Simmler MC, Brown L, Rouyer F, Noel B, Botstein D, de la Chapelle A, Weissenbach J. A deletion map of the human Y chromosome based on DNA hybridization. Am J Hum Genet 1986; 38:109-24. [PMID: 3004206 PMCID: PMC1684749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The genomes of 27 individuals (19 XX males, two XX hermaphrodites, and six persons with microscopically detectable anomalies of the Y chromosome) were analyzed by hybridization for the presence or absence of 23 Y-specific DNA restriction fragments. Y-specific DNA was detected in 12 of the XX males and in all six individuals with microscopic anomalies. The results are consistent with each of these individuals carrying a single contiguous portion of the Y chromosome; that is, the results suggest a deletion map of the Y chromosome, in which each of the 23 Y-specific restriction fragments tested can be assigned to one of seven intervals. We have established the polarity of this map with respect to the long and short arms of the Y chromosome. On the short arm, there is a large cluster of sequences homologous to the X chromosome. The testis determinant(s) map to one of the intervals on the short arm.
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Rouyer F, Simmler MC, Johnsson C, Vergnaud G, Cooke HJ, Weissenbach J. A gradient of sex linkage in the pseudoautosomal region of the human sex chromosomes. Nature 1986; 319:291-5. [PMID: 3941746 DOI: 10.1038/319291a0] [Citation(s) in RCA: 209] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Three independent pseudoautosomal loci are linked to sex determination at frequencies which define a gradient of linkage. The segregation patterns of these loci indicate that X/Y recombination results from a single obligatory meiotic crossing-over in the pseudoautosomal region. Recombination in male germ cells in the terminal regions of the short arms of the X and Y chromosomes in 10-fold greater than between the same regions of the X chromosomes in female germ cells.
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38
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Rouyer F, Simmler MC, Vergnaud G, Johnsson C, Levilliers J, Petit C, Weissenbach J. The pseudoautosomal region of the human sex chromosomes. Cold Spring Harb Symp Quant Biol 1986; 51 Pt 1:221-8. [PMID: 3472718 DOI: 10.1101/sqb.1986.051.01.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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39
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Simmler MC, Rouyer F, Vergnaud G, Nyström-Lahti M, Ngo KY, de la Chapelle A, Weissenbach J. Pseudoautosomal DNA sequences in the pairing region of the human sex chromosomes. Nature 1985; 317:692-7. [PMID: 2997620 DOI: 10.1038/317692a0] [Citation(s) in RCA: 132] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A DNA probe from a human Y chromosome-derived cosmid detects a single-copy genomic DNA fragment which can appear in different allelic forms shared by both sex chromosomes. Variants at this DNA locus show an autosomal pattern of inheritance, undergo recombination with sexual phenotype and can therefore be described as 'pseudoautosomal'. Another probe from the same cosmid detects a sequence repeated 15-20 times per haploid genome. These repeats also appear pseudoautosomal and map exclusively to the short-arm terminal region of each sex chromosome.
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