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Treveil A, Sudhakar P, Matthews ZJ, Wrzesiński T, Jones EJ, Brooks J, Ölbei M, Hautefort I, Hall LJ, Carding SR, Mayer U, Powell PP, Wileman T, Di Palma F, Haerty W, Korcsmáros T. Regulatory network analysis of Paneth cell and goblet cell enriched gut organoids using transcriptomics approaches. Mol Omics 2021; 16:39-58. [PMID: 31819932 DOI: 10.1039/c9mo00130a] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The epithelial lining of the small intestine consists of multiple cell types, including Paneth cells and goblet cells, that work in cohort to maintain gut health. 3D in vitro cultures of human primary epithelial cells, called organoids, have become a key model to study the functions of Paneth cells and goblet cells in normal and diseased conditions. Advances in these models include the ability to skew differentiation to particular lineages, providing a useful tool to study cell type specific function/dysfunction in the context of the epithelium. Here, we use comprehensive profiling of mRNA, microRNA and long non-coding RNA expression to confirm that Paneth cell and goblet cell enrichment of murine small intestinal organoids (enteroids) establishes a physiologically accurate model. We employ network analysis to infer the regulatory landscape altered by skewing differentiation, and using knowledge of cell type specific markers, we predict key regulators of cell type specific functions: Cebpa, Jun, Nr1d1 and Rxra specific to Paneth cells, Gfi1b and Myc specific for goblet cells and Ets1, Nr3c1 and Vdr shared between them. Links identified between these regulators and cellular phenotypes of inflammatory bowel disease (IBD) suggest that global regulatory rewiring during or after differentiation of Paneth cells and goblet cells could contribute to IBD aetiology. Future application of cell type enriched enteroids combined with the presented computational workflow can be used to disentangle multifactorial mechanisms of these cell types and propose regulators whose pharmacological targeting could be advantageous in treating IBD patients with Crohn's disease or ulcerative colitis.
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Affiliation(s)
- A Treveil
- Earlham Institute, Norwich Research Park, Norwich, Norfolk NR4 7UZ, UK.
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Mayer U, Benditz A, Grässel S. miR-29b regulates expression of collagens I and III in chondrogenically differentiating BMSC in an osteoarthritic environment. Sci Rep 2017; 7:13297. [PMID: 29038440 PMCID: PMC5643533 DOI: 10.1038/s41598-017-13567-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/26/2017] [Indexed: 12/13/2022] Open
Abstract
Osteoarthritis (OA) is characterized by a slowly progressing, irreversible loss of articular cartilage. Tissue engineering approaches for cartilage regeneration include stem cell-based strategies but not much is known about their repair capacity in an OA microenvironment. The aim of the present study was to identify factors regulating collagen expression during chondrogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSC) in an OA microenvironment. Coculture with OA cartilage induced miR-29b expression in BMSC which inhibited collagen I and III expression. Elevated miR-29b expression resulted in higher caspase 3/7 activity and promoted apoptosis of BMSC in part by directly inhibiting the anti-apoptotic proteins Bcl-2 and Mcl-1. Stimulation with IFN-γ induced miR-29b expression in BMSC. Our results suggest that miR-29b affects BMSC-based OA cartilage regeneration because expression of collagen III, mainly produced by undifferentiated BMSC, and collagen I, a marker for dedifferentiated chondrocytes, are inhibited by miR-29b thus influencing composition of the newly formed ECM. This might be critical to avoid formation of inferior fibrocartilage instead of hyaline cartilage. Furthermore, higher miR-29b expression promotes apoptosis either preventing excessive cell growth or reducing the number of BMSC undergoing chondrogenesis. Thus, miR-29b has both supportive but possibly also unfavourable effects on BMSC-based OA cartilage regeneration.
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Affiliation(s)
- Ute Mayer
- Department Orthopaedic Surgery, Exp. Orthopaedics, ZMB/Biopark 1, University of Regensburg, Regensburg, Germany.,Department Orthopaedic Surgery, Asklepiosklinikum, Bad Abbach, Germany
| | - Achim Benditz
- Department Orthopaedic Surgery, Asklepiosklinikum, Bad Abbach, Germany
| | - Susanne Grässel
- Department Orthopaedic Surgery, Exp. Orthopaedics, ZMB/Biopark 1, University of Regensburg, Regensburg, Germany. .,Department Orthopaedic Surgery, Asklepiosklinikum, Bad Abbach, Germany.
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3
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Merker S, Reif A, Ziegler GC, Weber H, Mayer U, Ehlis AC, Conzelmann A, Johansson S, Müller-Reible C, Nanda I, Haaf T, Ullmann R, Romanos M, Fallgatter AJ, Pauli P, Strekalova T, Jansch C, Vasquez AA, Haavik J, Ribasés M, Ramos-Quiroga JA, Buitelaar JK, Franke B, Lesch KP. SLC2A3 single-nucleotide polymorphism and duplication influence cognitive processing and population-specific risk for attention-deficit/hyperactivity disorder. J Child Psychol Psychiatry 2017; 58:798-809. [PMID: 28224622 DOI: 10.1111/jcpp.12702] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/14/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) is a common, highly heritable neurodevelopmental disorder with profound cognitive, behavioral, and psychosocial impairments with persistence across the life cycle. Our initial genome-wide screening approach for copy number variants (CNVs) in ADHD implicated a duplication of SLC2A3, encoding glucose transporter-3 (GLUT3). GLUT3 plays a critical role in cerebral glucose metabolism, providing energy for the activity of neurons, which, in turn, moderates the excitatory-inhibitory balance impacting both brain development and activity-dependent neural plasticity. We therefore aimed to provide additional genetic and functional evidence for GLUT3 dysfunction in ADHD. METHODS Case-control association analyses of SLC2A3 single-nucleotide polymorphisms (SNPs) and CNVs were conducted in several European cohorts of patients with childhood and adult ADHD (SNP, n = 1,886 vs. 1,988; CNV, n = 1,692 vs. 1,721). These studies were complemented by SLC2A3 expression analyses in peripheral cells, functional EEG recordings during neurocognitive tasks, and ratings of food energy content. RESULTS Meta-analysis of all cohorts detected an association of SNP rs12842 with ADHD. While CNV analysis detected a population-specific enrichment of SLC2A3 duplications only in German ADHD patients, the CNV + rs12842 haplotype influenced ADHD risk in both the German and Spanish cohorts. Duplication carriers displayed elevated SLC2A3 mRNA expression in peripheral blood cells and altered event-related potentials reflecting deficits in working memory and cognitive response control, both endophenotypic traits of ADHD, and an underestimation of energy units of high-caloric food. CONCLUSIONS Taken together, our results indicate that both common and rare SLC2A3 variation impacting regulation of neuronal glucose utilization and energy homeostasis may result in neurocognitive deficits known to contribute to ADHD risk.
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Affiliation(s)
- Sören Merker
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany
| | - Andreas Reif
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Frankfurt, Frankfurt, Germany
| | - Georg C Ziegler
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany
| | - Heike Weber
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany.,Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Frankfurt, Frankfurt, Germany
| | - Ute Mayer
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany
| | - Ann-Christine Ehlis
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Annette Conzelmann
- Department of Psychology I, University of Würzburg, Würzburg, Germany.,Department of Child and Adolescent Psychiatry, University of Tübingen, Tübingen, Germany
| | - Stefan Johansson
- K.G. Jebsen Centre for Neuropsychiatric Disorders, Department of Clinical Science, University of Bergen, Bergen, Norway
| | | | - Indrajit Nanda
- Department of Human Genetics, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Thomas Haaf
- Department of Human Genetics, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Reinhard Ullmann
- Max-Planck Institute for Molecular Genetics, Berlin, Germany.,Bundeswehr Institute of Radiobiology, University of Ulm, Ulm, Germany
| | - Marcel Romanos
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Andreas J Fallgatter
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Paul Pauli
- Department of Psychology I, University of Würzburg, Würzburg, Germany
| | - Tatyana Strekalova
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany.,Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, I.M. Sechenov First Moscow State Medical University, Moscow, Russia.,Department of Translational Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Charline Jansch
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany
| | - Alejandro Arias Vasquez
- Departments of Human Genetics and Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jan Haavik
- Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.,Department of Biomedicine, K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - Marta Ribasés
- Psychiatric Genetics Unit, Institute Vall d'Hebron Research (VHIR), Universitat Autonoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Mental Health (CIBERSAM), Barcelona, Spain
| | - Josep Antoni Ramos-Quiroga
- Psychiatric Genetics Unit, Institute Vall d'Hebron Research (VHIR), Universitat Autonoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Mental Health (CIBERSAM), Barcelona, Spain.,Department of Psychiatry and Legal Medicine, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Jan K Buitelaar
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Barbara Franke
- Departments of Human Genetics and Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Klaus-Peter Lesch
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany.,Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, I.M. Sechenov First Moscow State Medical University, Moscow, Russia.,Department of Translational Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
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Zechner A, Stock M, Kellner D, Ziegler I, Keuschnigg P, Huber P, Mayer U, Sedlmayer F, Deutschmann H, Steininger P. Development and first use of a novel cylindrical ball bearing phantom for 9-DOF geometric calibrations of flat panel imaging devices used in image-guided ion beam therapy. Phys Med Biol 2016; 61:N592-N605. [DOI: 10.1088/0031-9155/61/22/n592] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Rosa Salva O, Mayer U, Vallortigara G. Roots of a social brain: Developmental models of emerging animacy-detection mechanisms. Neurosci Biobehav Rev 2015; 50:150-68. [DOI: 10.1016/j.neubiorev.2014.12.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 12/16/2014] [Accepted: 12/18/2014] [Indexed: 10/24/2022]
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Auweter H, Mayer U, Schmid D. Singlet-Exciton Energy Transfer in Naphthalene Doped with Anthracene Following Two-Photon Picosecond Excitation: Dependence on Dopant Concentration. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/zna-1978-0605] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The time dependence of the sensitized fluorescence of anthracene-doped naphthalene crystals following two-photon picosecond excitation was studied for various dopant concentrations. The experimental results indicate that the characteristic of the energy transfer rate is significantly different for different anthracene concentrations. This behaviour is discussed in terms of different transfer mechanisms taking place at low and high dopant concentrations.
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Affiliation(s)
- H. Auweter
- Physikalisches Institut, Teil 3, Universität Stuttgart
| | - U. Mayer
- Physikalisches Institut, Teil 3, Universität Stuttgart
| | - D. Schmid
- Physikalisches Institut, Teil 3, Universität Stuttgart
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Auweter H, Braun A, Mayer U, Schmid D. Dynamics of Energy Transfer by Singlet Excitons in Naphthalene Crystals as Studied by Time-Resolved Spectroscopy. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/zna-1979-0615] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The time-resolved sensitized fluorescence of anthracene-doped naphthalene crystals following picosecond-pulse excitation was investigated experimentally as a function of dopant concentration and temperature. The influence of the excitation intensity on the decay of pure naphthalene crystals is studied and yields an almost temperature-independent annihilation constant, yss ≈ 4 x 10-11 cm3 s-1 . The analysis of the time-resolved host and guest fluorescence shows that the energy transfer rate, kHG > changes its functional form with the guest concentration. The temperature dependence of the energy transfer rate is explained tentatively in terms of phonon relaxation and phonon promotion processes.
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Affiliation(s)
- H. Auweter
- Physikalisches Institut, Teil 3, Universität Stuttgart
- Present address: Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - A. Braun
- Physikalisches Institut, Teil 3, Universität Stuttgart
| | - U. Mayer
- Physikalisches Institut, Teil 3, Universität Stuttgart
| | - D. Schmid
- Physikalisches Institut, Teil 3, Universität Stuttgart
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8
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Gutknecht L, Araragi N, Merker S, Waider J, Sommerlandt FMJ, Mlinar B, Baccini G, Mayer U, Proft F, Hamon M, Schmitt AG, Corradetti R, Lanfumey L, Lesch KP. Impacts of brain serotonin deficiency following Tph2 inactivation on development and raphe neuron serotonergic specification. PLoS One 2012; 7:e43157. [PMID: 22912815 PMCID: PMC3422228 DOI: 10.1371/journal.pone.0043157] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [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: 02/05/2012] [Accepted: 07/17/2012] [Indexed: 11/21/2022] Open
Abstract
Brain serotonin (5-HT) is implicated in a wide range of functions from basic physiological mechanisms to complex behaviors, including neuropsychiatric conditions, as well as in developmental processes. Increasing evidence links 5-HT signaling alterations during development to emotional dysregulation and psychopathology in adult age. To further analyze the importance of brain 5-HT in somatic and brain development and function, and more specifically differentiation and specification of the serotonergic system itself, we generated a mouse model with brain-specific 5-HT deficiency resulting from a genetically driven constitutive inactivation of neuronal tryptophan hydroxylase-2 (Tph2). Tph2 inactivation (Tph2−/−) resulted in brain 5-HT deficiency leading to growth retardation and persistent leanness, whereas a sex- and age-dependent increase in body weight was observed in Tph2+/− mice. The conserved expression pattern of the 5-HT neuron-specific markers (except Tph2 and 5-HT) demonstrates that brain 5-HT synthesis is not a prerequisite for the proliferation, differentiation and survival of raphe neurons subjected to the developmental program of serotonergic specification. Furthermore, although these neurons are unable to synthesize 5-HT from the precursor tryptophan, they still display electrophysiological properties characteristic of 5-HT neurons. Moreover, 5-HT deficiency induces an up-regulation of 5-HT1A and 5-HT1B receptors across brain regions as well as a reduction of norepinephrine concentrations accompanied by a reduced number of noradrenergic neurons. Together, our results characterize developmental, neurochemical, neurobiological and electrophysiological consequences of brain-specific 5-HT deficiency, reveal a dual dose-dependent role of 5-HT in body weight regulation and show that differentiation of serotonergic neuron phenotype is independent from endogenous 5-HT synthesis.
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Affiliation(s)
- Lise Gutknecht
- Molecular Psychiatry, Laboratory of Translational Neuroscience, Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
- * E-mail: (LG); (KPL)
| | - Naozumi Araragi
- Molecular Psychiatry, Laboratory of Translational Neuroscience, Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
| | - Sören Merker
- Molecular Psychiatry, Laboratory of Translational Neuroscience, Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
| | - Jonas Waider
- Molecular Psychiatry, Laboratory of Translational Neuroscience, Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
| | - Frank M. J. Sommerlandt
- Molecular Psychiatry, Laboratory of Translational Neuroscience, Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
| | - Boris Mlinar
- Department of Preclinical and Clinical Pharmacology, University of Florence, Florence, Italy
| | - Gilda Baccini
- Department of Preclinical and Clinical Pharmacology, University of Florence, Florence, Italy
| | - Ute Mayer
- Molecular Psychiatry, Laboratory of Translational Neuroscience, Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
| | - Florian Proft
- Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
| | - Michel Hamon
- Center of Psychiatry and Neuroscience, National Institute for Health and Medical Research (INSERM U894), Medical Faculty Pierre and Marie Curie, Paris, France
| | - Angelika G. Schmitt
- Molecular Psychiatry, Laboratory of Translational Neuroscience, Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
- Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
| | - Renato Corradetti
- Department of Preclinical and Clinical Pharmacology, University of Florence, Florence, Italy
| | - Laurence Lanfumey
- Center of Psychiatry and Neuroscience, National Institute for Health and Medical Research (INSERM U894), Medical Faculty Pierre and Marie Curie, Paris, France
| | - Klaus-Peter Lesch
- Molecular Psychiatry, Laboratory of Translational Neuroscience, Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
- * E-mail: (LG); (KPL)
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Abstract
The treatment of emergencies in a hospital should be organized in a central interdisciplinary emergency department (ER). It is the main entrance for all patients with acute illness or injuries. There are multiple advantages of such a central unit. Quality of treatment and economic efficiency is improved. The interdisciplinary diagnostics and treatment at one place prevents time-consuming and unnecessary transport. The fact that more complex diseases and injuries need specialized doctors in specific disciplines should be considered in personnel planning of the ER. To reinsure that the entire medical staff of the hospital is familiar with the daily routine and clinical pathways of the ER, doctors from other departments of the hospital should always be part of the ER team.
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Affiliation(s)
- U Mayer
- Zentrale Notaufnahme, Universitätsklinikum Hamburg Eppendorf, Martinistrasse 52, Hamburg, Germany.
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10
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Ackroyd M, Whitmore C, Nikolic M, Mayer U, Muntoni F, Brown S. O17 Novel insight in muscle and brain involvement in dystroglycanopathies. Neuromuscul Disord 2011. [DOI: 10.1016/s0960-8966(11)70018-9] [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: 11/28/2022]
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13
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Klimmeck D, Mayer U, Ungerer N, Warnken U, Schnölzer M, Frings S, Möhrlen F. Calcium-signaling networks in olfactory receptor neurons. Neuroscience 2007; 151:901-12. [PMID: 18155848 DOI: 10.1016/j.neuroscience.2007.11.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 10/31/2007] [Accepted: 11/16/2007] [Indexed: 01/03/2023]
Abstract
The olfactory neuroepithelium represents a unique interface between the brain and the external environment. Olfactory function comprises a distinct set of molecular tasks: sensory signal transduction, cytoprotection and adult neurogenesis. A multitude of biochemical studies has revealed the central role of Ca(2+) signaling in the function of olfactory receptor neurons (ORNs). We set out to establish Ca(2+)-dependent signaling networks in ORN cilia by proteomic analysis. We subjected a ciliary membrane preparation to Ca(2+)/calmodulin-affinity chromatography using mild detergent conditions in order to maintain functional protein complexes involved in olfactory Ca(2+) signaling. Thus, calmodulin serves as a valuable tool to gain access to novel Ca(2+)-regulated protein complexes. Tandem mass spectrometry (nanoscale liquid-chromatography-electrospray injection) identified 123 distinct proteins. Ninety-seven proteins (79%) could be assigned to specific olfactory functions, including 32 to sensory signal transduction and 40 to cytoprotection. We point out novel perspectives for research on the Ca(2+)-signaling networks in the olfactory system of the rat.
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Affiliation(s)
- D Klimmeck
- Department of Molecular Physiology, Institute of Zoology, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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14
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Nadif-Savey R, Emerson M, Cartwright E, Mayer U, Neyses L. Alpha 7 integrin is essential for normal heart shape and function. J Mol Cell Cardiol 2006. [DOI: 10.1016/j.yjmcc.2006.03.242] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Smith NP, Losty PD, Connell MG, Mayer U, Jesudason EC. Abnormal lung development precedes oligohydramnios in a transgenic murine model of renal dysgenesis. J Urol 2006; 175:783-6. [PMID: 16407050 DOI: 10.1016/s0022-5347(05)00169-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [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] [Received: 04/19/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE Renal development regulates prenatal lung growth by maintaining fetal urine output and liquor volume. However, shared signaling pathways underpinning renal and lung morphogenesis indicate that lung hypoplasia in the presence of renal dysgenesis may not result from oligohydramnios alone. We used a transgenic model of renal agenesis/anuria to test whether lung hypoplasia precedes any possible influence of oligohydramnios. MATERIALS AND METHODS E12 lung primordia from normal and gamma1III4 deficient murine embryos (fetal anuria and renal agenesis-dysgenesis) were cultured for 72 hours. Morphological lung development was measured at 24, 48 and 78 hours by bud counting and tracings of lung epithelial contour using image analysis software and photomicrographs. Genotyping was performed by a separate blinded investigator. RESULTS E12 homozygous mutant lungs branched but had significant decreases in bud count, epithelial area and perimeter compared to heterozygous or WT controls. These changes presented prior to oligohydramnios and persisted in isolation from the developing renal tract throughout the 72-hour culture period. CONCLUSIONS Lethal lung hypoplasia seen at term in this model is present from the earliest stages of development, persists in vitro and, therefore, it is not consequent on renal dysfunction. These data implies that 1) fetal interventions for severe prenatal uropathies may have variable success for protecting future lung function and 2) patients with fetal uropathies may warrant greater scrutiny of prenatal lung growth and long-term postnatal lung function.
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Affiliation(s)
- N P Smith
- Division of Child Health, University of Liverpool, Liverpool, United Kingdom
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16
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Lopez MA, Mayer U, Hwang W, Taylor T, Hashmi MA, Jannapureddy SR, Boriek AM. Force transmission, compliance, and viscoelasticity are altered in the alpha7-integrin-null mouse diaphragm. Am J Physiol Cell Physiol 2005; 288:C282-9. [PMID: 15643051 DOI: 10.1152/ajpcell.00362.2003] [Citation(s) in RCA: 22] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Alpha7beta1 integrin is a transmembrane structural and receptor protein of skeletal muscles, and the absence of alpha7-integrin causes muscular dystrophy. We hypothesized that the absence of alpha7-integrin alters compliance and viscoelasticity and disrupts the mechanical coupling between passive transverse and axial contractile elements in the diaphragm. In vivo the diaphragm is loaded with pressure, and therefore axial and transverse length-tension relationships are important in assessing its function. We determined diaphragm passive length-tension relationships and the viscoelastic properties of its muscle in 1-month-old alpha7-integrin-null mice and age-matched controls. Furthermore, we measured the isometric contractile properties of the diaphragm from mutant and normal mice in the absence and presence of passive force applied in the transverse direction to fibers in 1-month-old and 5-month-old mutant mice. We found that compared with controls, the diaphragm direction of alpha7-integrin-null mutants showed 1) a significant decrease in muscle extensibility in 1-year-old mice, whereas muscle extensibility increased in the 1-month-old mice; 2) altered muscle viscoelasticity in the transverse direction of the muscle fibers of 1-month-old mice; 3) a significant increase in force-generating capacity in the diaphragms of 1-month-old mice, whereas in 5-month-old mice muscle contractility was depressed; and 4) significant reductions in mechanical coupling between longitudinal and transverse properties of the muscle fibers of 1-month-old mice. These findings suggest that alpha7-integrin serves an important mechanical function in the diaphragm by contributing to passive compliance, viscoelasticity, and modulation of its muscle contractile properties.
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Affiliation(s)
- M A Lopez
- Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA
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17
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Leemhuis J, Mayer U, Barth H, Schmidt G, Meyer DK. The small GTPase Rac is involved in clustering of hippocampal neurons and fasciculation of their neurites. Naunyn Schmiedebergs Arch Pharmacol 2004; 370:211-22. [PMID: 15338109 DOI: 10.1007/s00210-004-0965-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Accepted: 07/08/2004] [Indexed: 10/26/2022]
Abstract
In hippocampal neurons cultured from brains of newborn rats, the glutamate receptor agonist N-methyl-D-aspartate induced the clustering of neuronal perikarya and the fasciculation of neurites. In addition, N-methyl-D-aspartate activated the small GTPase Rac1. Other stimuli of Rac activity, such as the Rho kinase inhibitors Y-27632, H-1152, and H89, as well as the cytotoxic necrotizing factor-1 from Escherichia coli, also caused neuronal clustering and neurite bundling. In neurons transiently transfected with dominant negative Rac1N17 neither N-methyl-D-aspartate nor Y-27632 induced clustering and fasciculation. In addition, the PI3-kinase inhibitors wortmannin and LY-294002 prevented these effects, as did a dominant negative form of p110PI3-Kgamma. Time-lapse microscopy showed that lethal toxin from Clostridium sordellii, which inhibits Rac, and wortmannin blocked the neuronal migration induced by Y-27632. In contrast, only lethal toxin reversed the clustering and fasciculation induced by pre-treatment with Y-27632. This effect of the toxin may be due to inactivation of Ras, since FTI-277, which prevents the farnesylation of Ras and thereby inactivates the GTPase, also dissolved the preformed clusters. We suggest that active Rac and a PI3-kinase synergistically induce neuronal migration, whereas a Ras isoform is responsible for the lasting attachment of neurons necessary for clustering and neurite fasciculation.
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Affiliation(s)
- J Leemhuis
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Zentrum für Neurowissenschaften, Albert-Ludwigs-Universität, Albertstrasse 23, 79104 Freiburg, Germany
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18
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Affiliation(s)
- A Viestenz
- Augenklinik mit Poliklinik der Universität Erlangen-Nürnberg, Erlangen, Arne,
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19
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Previtali SC, Dina G, Nodari A, Fasolini M, Wrabetz L, Mayer U, Feltri ML, Quattrini A. Schwann cells synthesize alpha7beta1 integrin which is dispensable for peripheral nerve development and myelination. Mol Cell Neurosci 2003; 23:210-8. [PMID: 12812754 DOI: 10.1016/s1044-7431(03)00014-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [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: 02/07/2023] Open
Abstract
Defects in laminins or laminin receptors are responsible for various neuromuscular disorders, including peripheral neuropathies. Interactions between Schwann cells and their basal lamina are fundamental to peripheral nerve development and successful myelination. Selected laminins are expressed in the endoneurium, and their receptors are developmentally regulated during peripheral nerve formation. Loss-of-function mutations have confirmed the importance and the role of some of these molecules. Here we show for the first time that another laminin receptor, alpha7beta1 integrin, previously described only in neurons, is also expressed in Schwann cells. The expression of alpha7 appears postnatally, such that alpha7beta1 is the last laminin receptor expressed by differentiating Schwann cells. Genetic inactivation of the alpha7 subunit in mice does not affect peripheral nerve formation or the expression of other laminin receptors. Of note, alpha7beta1 is not necessary for basal lamina formation and myelination. Nonetheless, these data taken together with the previous demonstration of impaired axonal regrowth in alpha7-null mice suggest a possible Schwann cell-autonomous role for alpha7 in nerve regeneration.
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MESH Headings
- Animals
- Animals, Newborn
- Basement Membrane/metabolism
- Basement Membrane/pathology
- Basement Membrane/ultrastructure
- Cells, Cultured
- Gene Expression Regulation, Developmental/genetics
- Immunohistochemistry
- Integrins/biosynthesis
- Integrins/deficiency
- Integrins/genetics
- Laminin/genetics
- Laminin/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Electron
- Myelin Sheath/metabolism
- Myelin Sheath/ultrastructure
- Myopathies, Structural, Congenital/genetics
- Myopathies, Structural, Congenital/metabolism
- Myopathies, Structural, Congenital/pathology
- Nerve Fibers, Myelinated/metabolism
- Nerve Fibers, Myelinated/ultrastructure
- Nerve Regeneration/genetics
- Peripheral Nerves/growth & development
- Peripheral Nerves/metabolism
- Peripheral Nerves/ultrastructure
- Peripheral Nervous System Diseases/genetics
- Peripheral Nervous System Diseases/metabolism
- Peripheral Nervous System Diseases/physiopathology
- Rats
- Rats, Sprague-Dawley
- Schwann Cells/metabolism
- Schwann Cells/ultrastructure
- Spinal Nerve Roots/growth & development
- Spinal Nerve Roots/metabolism
- Spinal Nerve Roots/ultrastructure
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Affiliation(s)
- S C Previtali
- Neuropathology Unit, San Raffaele Scientific Institute, Milan, Italy.
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20
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Abstract
PURPOSE To report the ocular findings in cerebro-oculo-facial-skeletal syndrome or Pena-Shokeir-II syndrome. METHODS Case report. RESULTS A five-month-old male infant presented with bilateral posterior polar cataract, microphthalmos, nystagmus, and marked non-glaucomatous optic nerve atrophy. Systemic abnormalities such as microcephaly, micrognathia, flexion contractures of the elbows and knees, hypotonic musculature, and failure to thrive, with pronounced statomotor retardation, led to the diagnosis of cerebro-oculo-facial-skeletal syndrome or Pena-Shokeir-II syndrome. Cataract surgery did not improve the poor visual performance. CONCLUSIONS Cerebro-oculo-facial-skeletal syndrome (Pena-Shokeir-II syndrome) should be included in the differential diagnosis of bilateral microphthalmos, congenital cataract, nystagmus, and pronounced optic nerve atrophy, and cataract surgery does not markedly improve vision.
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Affiliation(s)
- J B Jonas
- Department of Ophthalmology, Eye Hospital, University Erlangen-Nürnberg, Germany.
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21
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22
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Abstract
KEULE is required for cytokinesis in Arabidopsis thaliana. We have positionally cloned the KEULE gene and shown that it encodes a Sec1 protein. KEULE is expressed throughout the plant, yet appears enriched in dividing tissues. Cytokinesis-defective mutant sectors were observed in all somatic tissues upon transformation of wild-type plants with a KEULE-green fluorescent protein gene fusion, suggesting that KEULE is required not only during embryogenesis, but at all stages of the plant's life cycle. KEULE is characteristic of a Sec1 protein in that it appears to exist in two forms: soluble or peripherally associated with membranes. More importantly, KEULE binds the cytokinesis-specific syntaxin KNOLLE. Sec1 proteins are key regulators of vesicle trafficking, capable of integrating a large number of intra- and/or intercellular signals. As a cytokinesis-related Sec1 protein, KEULE appears to represent a novel link between cell cycle progression and the membrane fusion apparatus.
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Affiliation(s)
- F F Assaad
- Genetics and Microbiology Institute, Ludwig Maximilians University, D-80638 Munich, Germany.
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23
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Waizenegger I, Lukowitz W, Assaad F, Schwarz H, Jürgens G, Mayer U. The Arabidopsis KNOLLE and KEULE genes interact to promote vesicle fusion during cytokinesis. Curr Biol 2000; 10:1371-4. [PMID: 11084337 DOI: 10.1016/s0960-9822(00)00775-2] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.6] [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: 11/23/2022]
Abstract
Partitioning of the cytoplasm during cytokinesis or cellularisation requires syntaxin-mediated membrane fusion [1-3]. Whereas in animals, membrane fusion promotes ingression of a cleavage furrow from the plasma membrane [4,5], somatic cells of higher plants form de novo a transient membrane compartment, the cell plate, which is initiated in the centre of the division plane and matures into a new cell wall and its flanking plasma membranes [6,7]. Cell plate formation results from the fusion of Golgi-derived vesicles delivered by a dynamic cytoskeletal array, the phragmoplast. Mutations in two Arabidopsis genes, KNOLLE (KN) and KEULE (KEU), cause abnormal seedlings with multinucleate cells and incomplete cell walls [1,8]. The KN gene encodes a cytokinesis-specific syntaxin which localises to the cell plate [9]. Here, we show that KN protein localisation is unaffected in keu mutant cells, which, like kn, display phragmoplast microtubules and accumulate ADL1 protein in the plane of cell division but vesicles fail to fuse with one another. Genetic interactions between KN and KEU were analysed in double mutant embryos. Whereas the haploid gametophytes gave rise to functional gametes, the embryos behaved like single cells displaying multiple, synchronously cycling nuclei, cell cycle-dependent microtubule arrays and ADL1 accumulation between pairs of daughter nuclei. This complete inhibition of cytokinesis from fertilisation indicates that KN and KEU, have partially redundant functions and interact specifically in vesicle fusion during cytokinesis of somatic cells.
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Affiliation(s)
- I Waizenegger
- ZMBP, Entwicklungsgenetik, Universität Tübingen, Auf der Morgenstelle 1, Tübingen, Germany
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24
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Kröger N, Zabelina T, Sonnenberg S, Krüger W, Renges H, Stute N, Finkenstein F, Mayer U, Holstein K, Fiedler W, Colberg H, Sonnen R, Kuse R, Braumann D, Metzner B, del Valle F, Erttmann R, Kabisch H, Zander AR. Dose-dependent effect of etoposide in combination with busulfan plus cyclophosphamide as conditioning for stem cell transplantation in patients with acute myeloid leukemia. Bone Marrow Transplant 2000; 26:711-6. [PMID: 11042650 DOI: 10.1038/sj.bmt.1702598] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [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: 11/09/2022]
Abstract
To evaluate the efficacy and toxicity of two different etoposide (VP-16) dosages (30 or 45 mg/kg) in combination with busulfan/cyclophosphamide as conditioning therapy followed by stem cell transplantation in acute myeloid leukemia (AML), 90 patients with AML received either 30 mg/kg (n = 60) or 45 mg/kg (n = 30) etoposide in combination with busulfan (16 mg/kg) and cyclophosphamide (120 mg/kg). The stem cell source was allogeneic related bone marrow (BM) (n = 53), allogeneic unrelated BM (n = 5), allogeneic unrelated peripheral blood (PBSC) (n = 2), syngeneic BM (n = 2), autologous BM purged (n = 9) or unpurged (n = 9), autologous PBSC (n = 10). Fifty-six patients (62%) were in first CR, 26 (29%) were > first CR, and eight (9%) were transplanted in relapse. Principal toxicities in both groups were mucositis and hepatotoxicity. Forty-five mg/kg etoposide resulted in greater hepatic toxicity (P = 0.03), and a higher incidence of VOD (23 vs 12%, P = 0.04) and acute GVHD grade III/IV (13 vs 5%, NS). The treatment-related mortality was 17% in the 30 mg/kg group and 33% in the 45 mg/kg group, mainly due to infections, intestinal pneumonia and GVHD. Hematological recovery of leukocytes 1/nl was comparable in both groups (17 vs 16 days). After a median follow-up of 16 months 19% in the 30 mg/kg group and 23% in the 45 mg/kg group relapsed. In patients who had undergone allogeneic related bone marrow transplantation in first CR no relapses occurred after a median follow-up of 3 years. For all patients the 3-year estimated disease-free survival was 62% in the 30 mg/kg group and 40% in the 45 mg/kg group (P = 0.03). For patients in first CR who underwent allogeneic related stem cell transplantation the 3 year disease-free survivals were 80% and 66%, respectively (P = 0.4). We conclude that etoposide 30 mg/kg or 45 mg/kg in combination with busulfan/cyclophosphamide is a highly active regimen for bone marrow transplantation of patients with AML with a low relapse rate. However, conditioning with 30 mg/kg rather than 45 mg/kg etoposide resulted in less toxicity and a better overall survival due to a lower transplant-related mortality. Bone Marrow Transplantation (2000) 26, 711-716.
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Affiliation(s)
- N Kröger
- Bone Marrow Transplantation, University Hospital Hamburg-Eppendorf, Hamburg, Germany
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25
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Abstract
Higher plants have evolved specific mechanisms for partitioning the cytoplasm of dividing cells. In the predominant mode of phragmoplast-assisted cytokinesis, a cell wall and flanking plasma membranes are made de novo from a transient membrane compartment, the cell plate. which in turn forms by vesicle fusion from the centre to the periphery of the dividing cell. Other modes of cytokinesis appear to occur in meiotic cells and developing gametophytes. Here we review recent progress in the analysis of plant cytokinesis, focusing on genetic studies in Arabidopsis which are beginning to identify structural and regulatory components of phragmoplast-assisted cytokinesis. Two classes of mutations have been described. In one class, the defects appear to be confined to cell plate formation, suggesting that the execution of cytokinesis is specifically affected. Mutations in the other class display more general defects in cell division. We also discuss possible roles of proteins that have been localised in cytokinetic cells but not characterised genetically. Finally, mutations affecting meiotic or gametophytic cell divisions suggest that mechanistically different modes of cytokinesis occur in higher plants.
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Affiliation(s)
- P Nacry
- ZMBP Entwicklungsgenetik, Universität Tübingen, Germany
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26
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Schrick K, Mayer U, Horrichs A, Kuhnt C, Bellini C, Dangl J, Schmidt J, Jürgens G. FACKEL is a sterol C-14 reductase required for organized cell division and expansion in Arabidopsis embryogenesis. Genes Dev 2000. [PMID: 10859166 DOI: 10.1016/j.fcr.2008.07.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [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: 04/27/2023]
Abstract
In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. We report that FK is required for cell division and expansion and is involved in proper organization of the embryo. We isolated FK by positional cloning. Expression analysis in embryos revealed that FK mRNA becomes localized to meristematic zones. FK encodes a predicted integral membrane protein related to the vertebrate lamin B receptor and sterol reductases across species, including yeast sterol C-14 reductase ERG24. We provide functional evidence that FK encodes a sterol C-14 reductase by complementation of erg24. GC/MS analysis confirmed that fk mutations lead to accumulation of intermediates in the biosynthetic pathway preceding the C-14 reductase step. Although fk represents a sterol biosynthetic mutant, the phenotype was not rescued by feeding with brassinosteroids (BRs), the only plant sterol signaling molecules known so far. We propose that synthesis of sterol signals in addition to BRs is important in mediating regulated cell growth and organization during embryonic development. Our results indicate a novel role for sterols in the embryogenesis of plants.
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Affiliation(s)
- K Schrick
- Zentrum f]ur Molekularbiologie der Pflanzen, Universit]at T]ubingen, D-72076 T]ubingen, Germany.
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27
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Schrick K, Mayer U, Horrichs A, Kuhnt C, Bellini C, Dangl J, Schmidt J, Jürgens G. FACKEL is a sterol C-14 reductase required for organized cell division and expansion in Arabidopsis embryogenesis. Genes Dev 2000; 14:1471-84. [PMID: 10859166 PMCID: PMC316688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2000] [Accepted: 04/17/2000] [Indexed: 02/16/2023]
Abstract
In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. We report that FK is required for cell division and expansion and is involved in proper organization of the embryo. We isolated FK by positional cloning. Expression analysis in embryos revealed that FK mRNA becomes localized to meristematic zones. FK encodes a predicted integral membrane protein related to the vertebrate lamin B receptor and sterol reductases across species, including yeast sterol C-14 reductase ERG24. We provide functional evidence that FK encodes a sterol C-14 reductase by complementation of erg24. GC/MS analysis confirmed that fk mutations lead to accumulation of intermediates in the biosynthetic pathway preceding the C-14 reductase step. Although fk represents a sterol biosynthetic mutant, the phenotype was not rescued by feeding with brassinosteroids (BRs), the only plant sterol signaling molecules known so far. We propose that synthesis of sterol signals in addition to BRs is important in mediating regulated cell growth and organization during embryonic development. Our results indicate a novel role for sterols in the embryogenesis of plants.
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Affiliation(s)
- K Schrick
- Zentrum f]ur Molekularbiologie der Pflanzen, Universit]at T]ubingen, D-72076 T]ubingen, Germany.
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28
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Schrick K, Mayer U, Horrichs A, Kuhnt C, Bellini C, Dangl J, Schmidt J, Jürgens G. FACKEL is a sterol C-14 reductase required for organized cell division and expansion in Arabidopsis embryogenesis. Genes Dev 2000. [PMID: 10859166 DOI: 10.1101/gad.14.2.1471] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. We report that FK is required for cell division and expansion and is involved in proper organization of the embryo. We isolated FK by positional cloning. Expression analysis in embryos revealed that FK mRNA becomes localized to meristematic zones. FK encodes a predicted integral membrane protein related to the vertebrate lamin B receptor and sterol reductases across species, including yeast sterol C-14 reductase ERG24. We provide functional evidence that FK encodes a sterol C-14 reductase by complementation of erg24. GC/MS analysis confirmed that fk mutations lead to accumulation of intermediates in the biosynthetic pathway preceding the C-14 reductase step. Although fk represents a sterol biosynthetic mutant, the phenotype was not rescued by feeding with brassinosteroids (BRs), the only plant sterol signaling molecules known so far. We propose that synthesis of sterol signals in addition to BRs is important in mediating regulated cell growth and organization during embryonic development. Our results indicate a novel role for sterols in the embryogenesis of plants.
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Affiliation(s)
- K Schrick
- Zentrum f]ur Molekularbiologie der Pflanzen, Universit]at T]ubingen, D-72076 T]ubingen, Germany.
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29
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Vallant T, Brunner H, Kattner J, Mayer U, Hoffmann H, Leitner T, Friedbacher G, Schügerl G, Svagera R, Ebel M. Monolayer-Controlled Deposition of Silicon Oxide Films on Gold, Silicon, and Mica Substrates by Room-Temperature Adsorption and Oxidation of Alkylsiloxane Monolayers. J Phys Chem B 2000. [DOI: 10.1021/jp000006a] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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30
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Werner A, Willem M, Jones LL, Kreutzberg GW, Mayer U, Raivich G. Impaired axonal regeneration in alpha7 integrin-deficient mice. J Neurosci 2000; 20:1822-30. [PMID: 10684883 PMCID: PMC6772931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
The interplay between growing axons and the extracellular substrate is pivotal for directing axonal outgrowth during development and regeneration. Here we show an important role for the neuronal cell adhesion molecule alpha7beta1 integrin during peripheral nerve regeneration. Axotomy led to a strong increase of this integrin on regenerating motor and sensory neurons, but not on the normally nonregenerating CNS neurons. alpha7 and beta1 subunits were present on the axons and their growth cones in the regenerating facial nerve. Transgenic deletion of the alpha7 subunit caused a significant reduction of axonal elongation. The associated delay in the reinnervation of the whiskerpad, a peripheral target of the facial motor neurons, points to an important role for this integrin in the successful execution of axonal regeneration.
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Affiliation(s)
- A Werner
- Department of Neuromorphology, Max-Planck-Institute of Neurobiology, 82152 Martinsried, Germany
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31
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Jonas JB, Budde WM, Bergua A, Mayer U, Bartz-Schmidt KU. Linear naevus sebaceous syndrome, optic disc staphyloma, and non-rhegmatogenous retinal detachment. Br J Ophthalmol 2000; 84:119-20. [PMID: 10691330 PMCID: PMC1723229 DOI: 10.1136/bjo.84.1.117c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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32
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Miosge N, Klenczar C, Herken R, Willem M, Mayer U. Organization of the myotendinous junction is dependent on the presence of alpha7beta1 integrin. J Transl Med 1999; 79:1591-9. [PMID: 10616209] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
The laminin receptor alpha7beta1 is enriched at the myotendinous junctions, and mice with a targeted inactivation of the alpha7 gene develop a form of muscular dystrophy that primarily affects this structure. By ultrastructural analysis of alpha7-deficient mice, in comparison with wild-type and mdx mice, we attempted to elucidate the role of alpha7 integrin for the integrity and function of the myotendinous junctions. Ultrastructurally, myotendinous junctions of alpha7-deficient myofibers lose their interdigitations and the myofilaments retract from the sarcolemmal membrane, whereas the lateral side of the myofibers remains morphologically normal. The basement membrane at the myotendinous junctions in alpha7 -/- mice is significantly broadened, and immunogold-histochemistry has demonstrated that the laminin alpha2 chain is not localized here but, instead, in the matrix of the neighboring tendon. In contrast, mdx mice have normal myotendinous junctions, with a matrix protein pattern also found in wild-type mice, however the lateral sides of the myofibers are severely damaged. These results suggest that the alpha7beta1 integrin is a major receptor connecting the muscle cell to the tendon and helps to organize the myotendinous junction, whereas the dystrophin-glycoprotein complex is necessary for the lateral integrity of the muscle cell.
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Affiliation(s)
- N Miosge
- Zentrum Anatomie, Abteilung Histologie, Universität Göttingen, Germany.
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33
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Peterbauer T, Mucha J, Mayer U, Popp M, Glössl J, Richter A. Stachyose synthesis in seeds of adzuki bean (Vigna angularis): molecular cloning and functional expression of stachyose synthase. Plant J 1999; 20:509-518. [PMID: 10652123 DOI: 10.1046/j.1365-313x.1999.00618.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Stachyose is the major soluble carbohydrate in seeds of a number of important crop species. It is synthesized from raffinose and galactinol by the action of stachyose synthase (EC 2.4.1.67). We report here on the identification of a cDNA encoding stachyose synthase from seeds of adzuki bean (Vigna angularis Ohwi et Ohashi). Based on internal amino acid sequences of the enzyme purified from adzuki bean, oligonucleotides were designed and used to amplify corresponding sequences from adzuki bean cDNA by RT-PCR, followed by rapid amplification of cDNA ends (RACE-PCR). The complete cDNA sequence comprised 3046 nucleotides and included an open reading frame which encoded a polypeptide of 857 amino acid residues. The entire coding region was amplified by PCR, engineered into the baculovirus expression vector pVL1393 and introduced into Spodoptera frugiperda (Sf21) insect cells for heterologous expression. The recombinant protein was immunologically reactive with polyclonal antibodies raised against stachyose synthase purified from adzuki bean and was shown to be a functional stachyose synthase with the same catalytic properties as its native counterpart. High levels of stachyose synthase mRNA were transiently accumulated midway through seed development, and the enzyme was also present in mature seeds and during germination.
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Affiliation(s)
- T Peterbauer
- Institute of Plant Physiology, University of Vienna, A-1091 Vienna, Austria
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34
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Vignier N, Moghadaszadeh B, Gary F, Beckmann J, Mayer U, Guicheney P. Structure, genetic localization, and identification of the cardiac and skeletal muscle transcripts of the human integrin alpha7 gene (ITGA7). Biochem Biophys Res Commun 1999; 260:357-64. [PMID: 10403775 DOI: 10.1006/bbrc.1999.0916] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [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: 11/22/2022]
Abstract
We have determined the structure and the exon size pattern of the human integrin alpha7 subunit gene (ITGA7), which has been shown to be affected in a form of congenital myopathy. The gene is composed of at least 27 exons spanning a region of about 22.5 kb. The sequence of all exon/intron boundaries was determined and conforms to the GT/AG splicing consensus. We investigated the different splicing forms previously described in human and rodents. The major cytoplasmic variants alpha7A and alpha7B, which are developmentally regulated and tissue specific, were identified in human tissues, as well as the extracellular isoforms X1 and X2. The recently described D variant was detected in adult tissues by RT-PCR but not the C variant. We localized ITGA7 on chromosome 12q13 by high-resolution radiation hybrid mapping between D12S312 and D12S90 and identified a new CA-repeat microsatellite in intron 1.
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Affiliation(s)
- N Vignier
- INSERM U153, Groupe Hospitalier Pitié-Salpêtrière, Paris Cedex 13, 75651, France
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35
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Brunner H, Vallant T, Mayer U, Hoffmann H. Formation of Ultrathin Films at the Solid-Liquid Interface Studied by In Situ Ellipsometry. J Colloid Interface Sci 1999; 212:545-552. [PMID: 10092386 DOI: 10.1006/jcis.1998.6062] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ellipsometric investigations of self-assembled monolayers (SAMs) of alkylsiloxanes on native silicon substrates and of organothiols on gold substrates were performed under in situ conditions with the substrate in direct contact with the adsorbate solution. Specially designed liquid cells matched for different incidence angles were used to carry out measurements in a range of organic solvents with different refractive indices as the ambient medium. The observed shifts in the ellipsometric phase angles Delta upon monolayer formation were found to depend very sensitively on the incidence angle and the refractive indices of the adsorbate film and the ambient solvent, from which a rather simple method for determining the refractive index of the adsorbate film, based on a variation of the ambient refractive index, was derived. Time-resolved in situ measurements of SAM formation in different solvents and onto different substrates yielded accurate kinetic information on the monolayer growth process and revealed hitherto unknown strong solvent effects on the growth rate. Copyright 1999 Academic Press.
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Affiliation(s)
- H Brunner
- Department of Inorganic Chemistry, Vienna University of Technology, Getreidemark 9, Wien, A-1060, Austria
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Hamann T, Mayer U, Jürgens G. The auxin-insensitive bodenlos mutation affects primary root formation and apical-basal patterning in the Arabidopsis embryo. Development 1999; 126:1387-95. [PMID: 10068632 DOI: 10.1242/dev.126.7.1387] [Citation(s) in RCA: 261] [Impact Index Per Article: 10.4] [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: 11/20/2022]
Abstract
In Arabidopsis embryogenesis, the primary root meristem originates from descendants of both the apical and the basal daughter cell of the zygote. We have isolated a mutant of a new gene named BODENLOS (BDL) in which the primary root meristem is not formed whereas post-embryonic roots develop and bdl seedlings give rise to fertile adult plants. Some bdl seedlings lacked not only the root but also the hypocotyl, thus resembling monopteros (mp) seedlings. In addition, bdl seedlings were insensitive to the auxin analogue 2,4-D, as determined by comparison with auxin resistant1 (axr1) seedlings. bdl embryos deviated from normal development as early as the two-cell stage at which the apical daughter cell of the zygote had divided horizontally instead of vertically. Subsequently, the uppermost derivative of the basal daughter cell, which is normally destined to become the hypophysis, divided abnormally and failed to generate the quiescent centre of the root meristem and the central root cap. We also analysed double mutants. bdl mp embryos closely resembled the two single mutants, bdl and mp, at early stages, while bdl mp seedlings essentially consisted of hypocotyl but did form primary leaves. bdl axr1 embryos approached the mp phenotype at later stages, and bdl axr1 seedlings resembled mp seedlings. Our results suggest that BDL is involved in auxin-mediated processes of apical-basal patterning in the Arabidopsis embryo.
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Affiliation(s)
- T Hamann
- Entwicklungsgenetik, ZMBP, Universität Tübingen, Auf der Morgenstelle 1, D-72076 Tübingen, Germany
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Cohn RD, Mayer U, Saher G, Herrmann R, van der Flier A, Sonnenberg A, Sorokin L, Voit T. Secondary reduction of alpha7B integrin in laminin alpha2 deficient congenital muscular dystrophy supports an additional transmembrane link in skeletal muscle. J Neurol Sci 1999; 163:140-52. [PMID: 10371075 DOI: 10.1016/s0022-510x(99)00012-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [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: 11/19/2022]
Abstract
The integrins are a large family of heterodimeric transmembrane cellular receptors which mediate the association between the extracellular matrix (ECM) and cytoskeletal proteins. The alpha7beta1 integrin is a major laminin binding integrin in skeletal and cardiac muscle and is thought to be involved in myogenic differentiation and migration processes. The main binding partners of the alpha7 integrin are laminin-1 (alpha1-beta1-gamma1), laminin-2 (alpha2-beta1-gamma1) and laminin-4 (alpha2-beta2-gamma1). Targeted deletion of the gene for the alpha7 integrin subunit (ITGA7) in mice leads to a novel form of muscular dystrophy. In the present study we have investigated the expression of two alternative splice variants, the alpha7B and beta1D integrin subunits, in normal human skeletal muscle, as well as in various forms of muscular dystrophy. In normal human skeletal muscle the expression of the alpha7 integrin subunit appeared to be developmentally regulated: it was first detected at 2 years of age. In contrast, the beta1D integrin could be detected in immature and mature muscle in the sarcolemma of normal fetal skeletal muscle at 18 weeks gestation. The expression of alpha7B integrin was significantly reduced at the sarcolemma in six patients with laminin alpha2 chain deficient congenital muscular dystrophy (CMD) (age >2 years). However, this reduction was not correlated with the amount of laminin alpha2 chain expressed. In contrast, the expression of the laminin alpha2 chain was not altered in the skeletal muscle of the alpha7 knock-out mice. These data argue in favor that there is not a tight correlation between the expression of the alpha7 integrin subunit and that of the laminin alpha2 chain in either human or murine dystrophic muscle. Interestingly, in dystrophinopathies (Duchenne and Becker muscular dystrophy; DMD/BMD) expression of alpha7B was upregulated irrespective of the level of dystrophin expression as shown by a strong sarcolemmal staining pattern even in young boys (age <2 years). The expression of the beta1D integrin subunit was not altered in any of our patients with different types of muscular dystrophy. In contrast, sarcolemmal expression of beta1D integrin was significantly reduced in the alpha7 integrin knock-out mice, whereas the expression of the components of the DGC was not altered. The secondary loss of alpha7B in laminin alpha2 chain deficiency defines a biochemical change in the composition of the plasma membrane resulting from a primary protein deficiency in the basal lamina. These findings, in addition to the occurrence of a muscular dystrophy in alpha7 deficient mice, implies that the alpha7B integrin is an important laminin receptor within the plasma membrane which plays a significant role in skeletal muscle function and stability.
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Affiliation(s)
- R D Cohn
- Department of Pediatrics, University of Essen, Germany
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Mayer U, Herzog U, Berger F, Inzé D, Jürgens G. Mutations in the pilz group genes disrupt the microtubule cytoskeleton and uncouple cell cycle progression from cell division in Arabidopsis embryo and endosperm. Eur J Cell Biol 1999; 78:100-8. [PMID: 10099932 DOI: 10.1016/s0171-9335(99)80011-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [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: 11/26/2022] Open
Abstract
Organised cell division and expansion play important roles in plant embryogenesis. To address their cellular basis, we have analysed Arabidopsis abnormal-embryo mutants which were isolated for their characteristic phenotype: mutant embryos are small, mushroom-shaped ("pilz") and consist of only one or few large cells each containing one or more variably enlarged nuclei and often cell wall stubs. These 23 mutants represent four genes, PFIFFERLING, HALLIMASCH, CHAMPIGNON, and PORCINO, which map to different chromosomes. All four genes have very similar mutant phenotypes although porcino embryos often consisted of only one large cell. The endosperm did not cellularise and contained a variably reduced number of highly enlarged nuclei. By contrast, genetic evidence suggests that these genes are not required for gametophyte development. Expression of cell cycle genes, Cdc2a, CyclinA2 and CyclinB1, and the cytokinesis-specific KNOLLE gene was not altered in mutant embryos. However, KNOLLE syntaxin accumulated in patches but no KNOLLE-positive structure resembling a forming cell plate occurred in mitotic cells. A general defect in microtubule assembly was observed in all mutants. Interphase cells lacked cortical microtubules, and spindles were absent from mitotic nuclei although in rare cases, short stubs of microtubules were attached to partially condensed chromosomes. Our results suggest that the cellular components affected by the pilz group mutations are necessary for continuous microtubule organisation, mitotic division and cytokinesis but do not mediate cell cycle progression.
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Affiliation(s)
- U Mayer
- Lehrstuhl für Entwicklungsgenetik, Universität Tübingen, Germany.
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Abstract
In phragmoplast-assisted cytokinesis of somatic cells, vesicle fusion generates a cell plate that matures into a new cell wall and its flanking plasma membranes. Insight into this dynamic process has been gained in the past few years and additional molecular components of the basic machinery of cytokinesis have been identified. Specialized modes of cytokinesis occur in meiosis and gametophyte development, and recent studies indicate that they are genetically distinct from somatic cytokinesis.
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Affiliation(s)
- M Heese
- Lehrstuhl für Entwicklungsgenetik, Universität Tübingen, Auf der Morgenstelle 1, D-72076 Tübingen, Federal Republic of Germany
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Abstract
High-affinity binding of nidogen to laminins involves a single binding site on the laminin gamma 1 chain and is thus a property shared by almost all laminin isoforms. This binding mediates the connection of laminins to the collagen IV network, perlecan and other proteins and is considered to be an essential step in the stabilization of basement membranes. Nidogen binding has been located to a single LE module (gamma 1III4) by recombinant analysis. Site-directed mutagenesis and X-ray crystallography demonstrated that three amino acids (Asp, Asn, Val) in loop a of gamma 1III4 are crucial for binding and are supported by some other residues. A restricted complementary binding region seems to exist on nidogen domain G3. A mutant laminin gamma 1 chain gene that lacks the region encoding gamma 1III4 was prepared in mouse embryonic stem (ES) cells by homologous recombination. ES cells homozygous for this defect were shown to assemble laminin-1 into a cruciform structure and to secrete it properly. Yet the mutant laminin failed to associate with nidogen. The mutant ES cells were still able to form embryoid bodies with a similar differentiated histology as the wild type. Immunofluorescence, however, indicated an impaired deposition of nidogen into basement membrane-like structures.
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Affiliation(s)
- U Mayer
- Max-Planck-Institut für Biochemie, Martinsried, Germany
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Vallant T, Brunner H, Mayer U, Hoffmann H, Leitner T, Resch R, Friedbacher G. Formation of Self-Assembled Octadecylsiloxane Monolayers on Mica and Silicon Surfaces Studied by Atomic Force Microscopy and Infrared Spectroscopy. J Phys Chem B 1998. [DOI: 10.1021/jp981282g] [Citation(s) in RCA: 151] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Smith AJ, Mayer U, Schinkel AH, Borst P. Availability of PSC833, a substrate and inhibitor of P-glycoproteins, in various concentrations of serum. J Natl Cancer Inst 1998; 90:1161-6. [PMID: 9701366 DOI: 10.1093/jnci/90.15.1161] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [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: 11/14/2022] Open
Abstract
BACKGROUND P-glycoproteins are membrane-associated transporters that can render cells resistant to a variety of chemotherapeutic drugs. Reversal agents are (preferably nontoxic) drugs that can inhibit these P-glycoproteins and thereby overcome multidrug resistance. PSC833, a cyclosporin A analog, is a reversal agent that has shown potential in in vitro experiments and in clinical trials. We tested PSC833 to determine whether it is a transported substrate of human and murine P-glycoproteins associated with multidrug resistance (encoded by the human MDR1 gene and its murine homolog, mdr1a) and whether it can completely inhibit these P-glycoproteins under simulated in vivo conditions. METHODS Monolayers of polarized LLC-PK1 pig kidney cells transfected with complementary DNA containing either MDR1 or mdr1a sequences were used to measure the directional transport of P-glycoprotein substrates under various serum conditions. RESULTS In contrast to two previous studies, we found that PSC833 is transported by both the MDR1 and the mdr1a P-glycoproteins, albeit at a low rate. PSC833 has a very high affinity for the MDR1 P-glycoprotein, and its Michaelis constant (Km) for transport is 50 nM, fourfold lower than for cyclosporin A. Inhibition of drug transport by PSC833 is approximately eightfold less effective in 100% fetal bovine serum than in tissue culture medium containing 10% serum. The concentration of PSC833 necessary to fully inhibit transport of digoxin and paclitaxel (Taxol) under complete (i.e., 100%) serum conditions is higher than the plasma concentrations achieved in clinical trials. CONCLUSIONS Although PSC833 binds efficiently to the MDR1 P-glycoprotein and is released only sluggishly, the high concentrations of PSC833 necessary to inhibit this P-glycoprotein under complete serum conditions in our in vitro system suggest that it may be difficult for PSC833 alone to produce total inhibition of P-glycoprotein activity in patients.
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Affiliation(s)
- A J Smith
- Division of Molecular Biology, The Netherlands Cancer Institute, Amsterdam
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Smith AJ, Mayer U, Schinkel AH, Borst P. Availability of PSC833, a Substrate and Inhibitor of P-glycoproteins, in Various Concentrations of Serum. J Natl Cancer Inst 1998. [DOI: 10.1093/jnci/90.15.1611] [Citation(s) in RCA: 2] [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: 11/12/2022] Open
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Abstract
Pattern formation in embryogenesis generates the basic body plan of flowering plants by establishing the diversity of position-dependent cell fates characteristic of the seedling. The concept of pattern formation, which was originally based on the analysis of Arabidopsis pattern mutants, is re-examined in the light of recent data that address the origin of the axis of polarity, the origin of the primary meristems as elements of the apical-basal pattern and the formation of the radial pattern of tissue layers. The available evidence from genetic, molecular and experimental approaches supports the notion that embryonic pattern formation occurs in steps involving communication between clonally unrelated cells.
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Affiliation(s)
- U Mayer
- Lehrstuhl für Entwicklungsgenetik, Universität Tübingen, Federal Republic of Germany
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Frischholz S, Beier F, Girkontaite I, Wagner K, Pöschl E, Turnay J, Mayer U, von der Mark K. Characterization of human type X procollagen and its NC-1 domain expressed as recombinant proteins in HEK293 cells. J Biol Chem 1998; 273:4547-55. [PMID: 9468510 DOI: 10.1074/jbc.273.8.4547] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [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: 02/06/2023] Open
Abstract
Type X collagen is a short-chain, network-forming collagen found in hypertrophic cartilage in the growth zones of long bones, vertebrae, and ribs. To obtain information about the structure and assembly of mammalian type X collagen, we generated recombinant human type collagen X by stable expression of full-length human alpha1(X) cDNA in the human embryonal kidney cell line HEK293 and the fibrosarcoma cell line HT1080. Stable clones were obtained secreting recombinant human type X collagen (hrColX) in amounts of 50 microg/ml with alpha1(X)-chains of apparent molecular mass of 75 kDa. Pepsin digestion converted the native protein to a molecule migrating as one band at 65 kDa, while bands of 55 and 43 kDa were generated by trypsin digestion. Polyclonal antibodies prepared against purified hrColX reacted specifically with type X collagen in sections of human fetal growth cartilage. Circular dichroism spectra and trypsin/chymotrypsin digestion experiments of hrColX at increasing temperatures indicated triple helical molecules with a reduced melting temperature of 31 degrees C as a result of partial underhydroxylation. Ultrastructural analysis of hrColX by rotary shadowing demonstrated rodlike molecules with a length of 130 nm, assembling into aggregates via the globular noncollagenous (NC)-1 domains as reported for chick type X collagen. NC-1 domains generated by collagenase digestion of hrColX migrated as multimers of apparent mass of 40 kDa on SDS-polyacrylamide gel electrophoresis, even after reduction and heat denaturation, and gave rise to monomers of 18-20 kDa after treatment with trichloroacetic acid. The NC-1 domains prepared by collagenase digestion comigrated with NC-1 domains prepared as recombinant protein in HEK293 cells, both in the multimeric and monomeric form. These studies demonstrate the potential of the pCMVsis expression system to produce recombinant triple helical type X collagens in amounts sufficient for further studies on its structural and functional domains.
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Affiliation(s)
- S Frischholz
- Institute of Experimental Medicine, Friedrich Alexander University, Erlangen, Germany
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Lauber MH, Waizenegger I, Steinmann T, Schwarz H, Mayer U, Hwang I, Lukowitz W, Jürgens G. The Arabidopsis KNOLLE protein is a cytokinesis-specific syntaxin. J Biophys Biochem Cytol 1997; 139:1485-93. [PMID: 9396754 PMCID: PMC2132613 DOI: 10.1083/jcb.139.6.1485] [Citation(s) in RCA: 400] [Impact Index Per Article: 14.8] [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] [Indexed: 02/05/2023] Open
Abstract
In higher plant cytokinesis, plasma membrane and cell wall originate by vesicle fusion in the plane of cell division. The Arabidopsis KNOLLE gene, which is required for cytokinesis, encodes a protein related to vesicle-docking syntaxins. We have raised specific rabbit antiserum against purified recombinant KNOLLE protein to show biochemically and by immunoelectron microscopy that KNOLLE protein is membrane associated. Using immunofluorescence microscopy, KNOLLE protein was found to be specifically expressed during mitosis and, unlike the plasma membrane H+-ATPase, to localize to the plane of division during cytokinesis. Arabidopsis dynamin-like protein ADL1 accumulates at the plane of cell plate formation in knolle mutant cells as in wild-type cells, suggesting that cytokinetic vesicle traffic is not affected. Furthermore, electron microscopic analysis indicates that vesicle fusion is impaired. KNOLLE protein was detected in mitotically dividing cells of various parts of the developing plant, including seedling root, inflorescence meristem, floral meristems and ovules, and the cellularizing endosperm, but not during cytokinesis after the male second meiotic division. Thus, KNOLLE is the first syntaxin-like protein that appears to be involved specifically in cytokinetic vesicle fusion.
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Affiliation(s)
- M H Lauber
- Lehrstuhl für Entwicklungsgenetik, Universität Tübingen, D-72076 Tübingen, Federal Republic of Germany
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Pfeiffer RA, Ulmer R, Rauch A, Trautmann U, Beinder E, Rupprecht T, Mayer U, Steinkirchner B, Wündisch GF. True fetal mosaicism of an isochromosome of the long arm of a chromosome 20: the dilemma persists. Prenat Diagn 1997; 17:1171-5. [PMID: 9467815 DOI: 10.1002/(sici)1097-0223(199712)17:12<1171::aid-pd181>3.0.co;2-k] [Citation(s) in RCA: 14] [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: 02/06/2023]
Abstract
We report the prenatal findings of mos 46,XY/46,XY,i(20q) after amniocentesis. The propositus presented with two epidermal scalp scars, retrobulbar orbital cysts, and dyssegmentation of the thoracic spine. The abnormal cell line was discovered in cells cultured from the proximal umbilical cord and--by fluorescence in situ hybridization (FISH)--in interphase nuclei from buccal epithelium and urinary sediment but not from the placenta, lymphocytes, or skin fibroblasts.
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Mayer U, Wagenaar E, Dorobek B, Beijnen JH, Borst P, Schinkel AH. Full blockade of intestinal P-glycoprotein and extensive inhibition of blood-brain barrier P-glycoprotein by oral treatment of mice with PSC833. J Clin Invest 1997; 100:2430-6. [PMID: 9366556 PMCID: PMC508442 DOI: 10.1172/jci119784] [Citation(s) in RCA: 195] [Impact Index Per Article: 7.2] [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: 02/05/2023] Open
Abstract
Mice lacking mdr1-type P-glycoproteins (mdr1a/1b [-/-] mice) display large changes in the pharmacokinetics of digoxin and other drugs. Using the kinetics of digoxin in mdr1a/1b (-/-) mice as a model representing a complete block of P-glycoprotein activity, we investigated the activity and specificity of the reversal agent SDZ PSC833 in inhibiting mdr1-type P-glycoproteins in vivo. Oral PSC833 was coadministered with intravenous [3H]digoxin to wild-type and mdr1a/1b (-/-) mice. The direct excretion of [3H]digoxin mediated by P-glycoprotein in the intestinal mucosa of wild-type mice was abolished by administration of PSC833. Hepatobiliary excretion of [3H]digoxin was markedly decreased in both wild-type and mdr1a/1b (-/-) mice by PSC833, the latter effect indicating that in vivo, PSC833 inhibits not only mdr1-type P-glycoproteins, but also other drug transporters. Upon coadministration of PSC833, brain levels of [3H]digoxin in wild-type mice showed a large increase, approaching (but not equaling) the levels found in brains of PSC833-treated mdr1a/1b (-/-) mice. Thus, orally administered PSC833 can inhibit blood-brain barrier P-glycoprotein extensively, and intestinal P-glycoprotein completely. These profound pharmacokinetic effects of PSC833 treatment imply potential risks, but also promising pharmacological applications of the use of effective reversal agents.
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Affiliation(s)
- U Mayer
- Division of Molecular Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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Mayer U, Saher G, Fässler R, Bornemann A, Echtermeyer F, von der Mark H, Miosge N, Pöschl E, von der Mark K. Absence of integrin alpha 7 causes a novel form of muscular dystrophy. Nat Genet 1997; 17:318-23. [PMID: 9354797 DOI: 10.1038/ng1197-318] [Citation(s) in RCA: 354] [Impact Index Per Article: 13.1] [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: 02/05/2023]
Abstract
Integrin alpha 7 beta 1 is a specific cellular receptor for the basement membrane protein laminin-1 (refs 1,2), as well as for the laminin isoforms -2 and -4 (ref. 3). The alpha 7 subunit is expressed mainly in skeletal and cardiac muscle and has been suggested to be involved in differentiation and migration processes during myogenesis. Three cytoplasmic and two extracellular splice variants that have been described are developmentally regulated and expressed in different sites in the muscle. In adult muscle, the alpha 7A and alpha 7B subunits are concentrated in myotendinous junctions but can also be detected in neuromuscular junctions and along the sarcolemmal membrane. To study the potential involvement of alpha 7 integrin, during myogenesis and its role in muscle integrity and function, we generated a null allele of the alpha 7 gene (Itga7) in the germline of mice by homologous recombination in embryonic stem (ES) cells. Surprisingly, mice homozygous for the mutation are viable and fertile, indicating that the alpha 7 beta 1 integrin is not essential for myogenesis. However, histological analysis of skeletal muscle revealed typical symptoms of a progressive muscular dystrophy starting soon after birth, but with a distinct variability in different muscle types. The observed histopathological changes strongly indicate an impairment of function of the myotendinous junctions. These findings demonstrate that alpha 7 beta 1 integrin represents an indispensable linkage between the muscle fibre and the extracellular matrix that is independent of the dystrophin-dystroglycan complex-mediated interaction of the cytoskeleton with the muscle basement membrane.
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Affiliation(s)
- U Mayer
- Max-Planck-Institute for Biochemistry, Martinsried, Germany.
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Wijnholds J, Evers R, van Leusden MR, Mol CA, Zaman GJ, Mayer U, Beijnen JH, van der Valk M, Krimpenfort P, Borst P. Increased sensitivity to anticancer drugs and decreased inflammatory response in mice lacking the multidrug resistance-associated protein. Nat Med 1997; 3:1275-9. [PMID: 9359705 DOI: 10.1038/nm1197-1275] [Citation(s) in RCA: 317] [Impact Index Per Article: 11.7] [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: 02/05/2023]
Abstract
The multidrug resistance-associated protein (MRP) mediates the cellular excretion of many drugs, glutathione S-conjugates (GS-X) of lipophilic xenobiotics and endogenous cysteinyl leukotrienes. Increased MRP levels in tumor cells can cause multidrug resistance (MDR) by decreasing the intracellular drug concentration. The physiological role or roles of MRP remain ill-defined, however. We have generated MRP-deficient mice by using embryonic stem cell technology. Mice homozygous for the mrp mutant allele, mrp-/-, are viable and fertile, but their response to an inflammatory stimulus is impaired. We attribute this defect to a decreased secretion of leukotriene C4 (LTC4) from leukotriene-synthesizing cells. Moreover, the mrp-/- mice are hypersensitive to the anticancer drug etoposide. The phenotype of mrp-/- mice is consistent with a role for MRP as the main LTC4-exporter in leukotriene-synthesizing cells, and as an important drug exporter in drug-sensitive cells. Our results suggest that this ubiquitous GS-X pump is dispensable in mice, making treatment of MDR with MRP-specific reversal agents potentially feasible.
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Affiliation(s)
- J Wijnholds
- Division of Molecular Biology, Netherlands Cancer Institute, Amsterdam
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