1
|
Niemeyer P, Schweigler K, Grotejohann B, Maurer J, Angele P, Aurich M, Becher C, Fay J, Feil R, Fickert S, Fritz J, Hoburg A, Kreuz P, Kolombe T, Laskowski J, Lützner J, Marlovits S, Müller P, Niethammer T, Pietschmann M, Ruhnau K, Spahn G, Tischer T, Zinser W, Albrecht D. Das KnorpelRegister DGOU zur Erfassung von Behandlungsergebnissen nach Knorpeloperationen: Erfahrungen nach 6 Monaten und erste epidemiologische Daten. Z Orthop Unfall 2015; 153:67-74. [DOI: 10.1055/s-0034-1383222] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- P. Niemeyer
- Department für Orthopädie und Traumatologie, Universitätsklinikum Freiburg
| | - K. Schweigler
- Department für Orthopädie und Traumatologie, Universitätsklinikum Freiburg
| | | | - J. Maurer
- Studienzentrum, Universitätsklinikum Freiburg
| | - P. Angele
- Sportorthopaedicum Regensburg/Straubing, Straubing
| | - M. Aurich
- Klinik für Orthopädische Chirurgie, Unfall- und Handchirurgie, Kliniken Leipziger Land, Borna
| | - C. Becher
- Orthopädische Klinik im Annastift, Medizinische Hochschule Hannover
| | - J. Fay
- Unfall- und Arthroskopische Chirurgie, Lubinus-Clinicum Kiel
| | - R. Feil
- Klinik für Unfallchirurgie, Orthopädie und Handchirurgie, Kath. Marienkrankenhaus, Hamburg
| | - S. Fickert
- Sportorthopaedicum Regensburg/Straubing, Straubing
| | - J. Fritz
- Orthopädisch-Chirurgisches Zentrum, Tübingen, Deutschland
| | - A. Hoburg
- Charité Berlin, Klinik für Orthopädische, Unfall- und Wiederherstellungschirurgie
| | - P. Kreuz
- Universitätskllinikum Rostock, Orthopädische Klinik und Poliklinik
| | - T. Kolombe
- Klinik für Orthopädie und Unfallchirurgie, DRK Krankenhaus Luckenwalde
| | - J. Laskowski
- Klinik für Unfallchirurgie, Orthopädie und Handchirurgie, Kath. Marienkrankenhaus, Hamburg
| | - J. Lützner
- UniversitätsCentrum für Orthopädie und Unfallchirurgie, Universitätsklinikum Dresden, Deutschland
| | - S. Marlovits
- Klinik für Unfallchirurgie, Medizinische Universität Wien, Österreich
| | - P. Müller
- Klinik und Poliklinik für Orthopädie, Physikalische Medizin und Rehabilitation, Ludwig-Maximilians-Universität, München
| | - T. Niethammer
- Klinik und Poliklinik für Orthopädie, Physikalische Medizin und Rehabilitation, Ludwig-Maximilians-Universität, München
| | - M. Pietschmann
- Klinik und Poliklinik für Orthopädie, Physikalische Medizin und Rehabilitation, Ludwig-Maximilians-Universität, München
| | - K. Ruhnau
- Fachklinik für Orthopädie und Orthopädische Chirurgie, Viktoriaklinik Bochum
| | - G. Spahn
- Praxisklinik für Orthopädie und Unfallchirurgie, Eisenach
| | - T. Tischer
- Universitätskllinikum Rostock, Orthopädische Klinik und Poliklinik
| | - W. Zinser
- Klinik für Orthopädie und Unfallchirurgie mit Sportmedizin und Alterstraumatologie, St. Vinzenz Hospital, Dinslaken
| | - D. Albrecht
- Chirurgie, Klinik im Kronprinzenbau, Reutlingen
| |
Collapse
|
2
|
Abstract
The mercuric EDTA dehydrogenation of the isomeric 1,2- and 2,1-(phenyl-pyrrolidino)-ethanols yields with two electron removal the corresponding oxazolidines. The analogous 1,2- and 2,1-(amino-phenyl)pyrrolidines by double dehydrogenation produce the amidines resp. by subsequent hydrolysis the lactams. An explanation for the different course of the reaction is given
Collapse
Affiliation(s)
- H. Möhrle
- Institut für Pharmazie der Freien Universität Berlin
| | - Chr. Kamper
- Institut für Pharmazie der Freien Universität Berlin
| | - R. Feil
- Institut für Pharmazie der Freien Universität Berlin
| |
Collapse
|
3
|
Takenouchi K, Shrestha B, Yamakuchi M, Yoshinaga N, Arimura N, Kawaguchi H, Nagasato T, Feil R, Kawahara K, Sakamoto T, Maruyama I, Hashiguchi T. Upregulation of non-β cell-derived vascular endothelial growth factor A increases small clusters of insulin-producing cells in the pancreas. Exp Clin Endocrinol Diabetes 2014; 122:308-15. [PMID: 24839224 DOI: 10.1055/s-0034-1371811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Pancreatic β cell-derived vascular endothelial growth factor A (VEGF-A) contributes to normal β cell function. We therefore hypothesized that non-β cell-derived VEGF-A may affect its properties in adult mice.We generated transgenic mice expressing human VEGF-A (hVEGF-A) in a visceral smooth muscle cell (SMC)-dominant manner under the control of the transgelin (Tagln/SM22α) promoter via a tamoxifen-induced Cre/loxP recombination system (SM-CreER(T2)/hVEGF mice).SM-CreER(T2)/hVEGF mice received tamoxifen orally followed by microscopic examination of their pancreas 4 weeks after the hVEGF-A induction. The number of clusters of insulin-producing cells (IPCs) in islets, pancreatic ducts, and individual IPCs were counted.The number of small IPC clusters (100-215 μm(2)) in the pancreas increased significantly in SM-CreER(T2)/hVEGF mice compared with SM-CreER(T2)(Ki) mice (473 out of 1 992 counts vs. 199 out of 976 counts, p<0.05), although total IPC area and the number of pancreatic duct IPCs, in proportion to exocrine area, were similar between the 2 groups. Although most small IPC clusters observed in SM-CreER(T2)/hVEGF mice were not accompanied by α and/or δ cells, some were attached to a single or a few α cells. An STZ-induced diabetic state in SM-CreER(T2)/hVEGF mice was slightly ameliorated, with only one point of significance 12 weeks after STZ administration, compared with SM-CreER(T2)(Ki) mice.Upregulation of non-β cell-derived VEGF-A may alter the composition of pancreatic IPCs by increasing the number of small IPC clusters. These findings provide new information on the role of non-β cell-derived VEGF-A to IPC regeneration and insulin production.
Collapse
Affiliation(s)
- K Takenouchi
- Department of Laboratory and Vascular Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan
| | - B Shrestha
- Department of Laboratory and Vascular Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan
| | - M Yamakuchi
- Department of Laboratory and Vascular Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan
| | - N Yoshinaga
- Department of Ophthalmology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan
| | - N Arimura
- Department of Ophthalmology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan
| | - H Kawaguchi
- Department of Veterinary Experimental Animal Science, Faculty of Agriculture, Kagoshima University, Korimoto, Kagoshima, Japan
| | - T Nagasato
- Systems Biology in Thromboregulation, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan
| | - R Feil
- Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany
| | - K Kawahara
- Laboratory of Functional Foods, Department of Biomedical Engineering Osaka Institute of Technology, Osaka, Japan
| | - T Sakamoto
- Department of Ophthalmology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan
| | - I Maruyama
- Systems Biology in Thromboregulation, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan
| | - T Hashiguchi
- Department of Laboratory and Vascular Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan
| |
Collapse
|
4
|
Wolf JB, Oakey RJ, Feil R. Imprinted gene expression in hybrids: perturbed mechanisms and evolutionary implications. Heredity (Edinb) 2014; 113:167-75. [PMID: 24619185 DOI: 10.1038/hdy.2014.11] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 01/24/2014] [Accepted: 01/28/2014] [Indexed: 01/21/2023] Open
Abstract
Diverse mechanisms contribute to the evolution of reproductive barriers, a process that is critical in speciation. Amongst these are alterations in gene products and in gene dosage that affect development and reproductive success in hybrid offspring. Because of its strict parent-of-origin dependence, genomic imprinting is thought to contribute to the aberrant phenotypes observed in interspecies hybrids in mammals and flowering plants, when the abnormalities depend on the directionality of the cross. In different groups of mammals, hybrid incompatibility has indeed been linked to loss of imprinting. Aberrant expression levels have been reported as well, including imprinted genes involved in development and growth. Recent studies in humans emphasize that genetic diversity within a species can readily perturb imprinted gene expression and phenotype as well. Despite novel insights into the underlying mechanisms, the full extent of imprinted gene perturbation still remains to be determined in the different hybrid systems. Here we review imprinted gene expression in intra- and interspecies hybrids and examine the evolutionary scenarios under which imprinting could contribute to hybrid incompatibilities. We discuss effects on development and reproduction and possible evolutionary implications.
Collapse
Affiliation(s)
- J B Wolf
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, UK
| | - R J Oakey
- Division of Genetics and Molecular Medicine, King's College London, London, UK
| | - R Feil
- Institute of Molecular Genetics (IGMM), CNRS, UMR-5535 and University of Montpellier, Montpellier, France
| |
Collapse
|
5
|
Welter H, Kampfer C, Lauf S, Feil R, Schwarzer JU, Köhn FM, Mayerhofer A. Partial loss of contractile marker proteins in human testicular peritubular cells in infertility patients. Andrology 2013; 1:318-24. [PMID: 23413143 DOI: 10.1111/j.2047-2927.2012.00030.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 09/20/2012] [Accepted: 09/24/2012] [Indexed: 12/16/2023]
Abstract
Fibrotic remodelling of the testicular tubular wall is common in human male infertility caused by impaired spermatogenesis. We hypothesized that this morphological change bears witness of an underlying fundamentally altered state of the cells building this wall, that is, peritubular smooth muscle-like cells. This could include a loss of the contractile abilities of these cells and thus be a factor in male infertility. Immune cells are increased in the tubular wall in these cases, hence local immune cell-related factors, including a prostaglandin (PG) metabolite may be involved. To explore these points in the human, we used testicular biopsies, in which tubules with normal spermatogenesis and impaired spermatogenesis are next to each other [mixed atrophy (MA)], normal biopsies and cultured human testicular peritubular cells. Proteins essential for contraction, myosin heavy chain (MYH11), calponin (Cal) and relaxation, cGMP-dependent protein kinase 1 (cGKI), were readily detected by immunohistochemistry and were equally distributed in all peritubular cells of biopsies with normal spermatogenesis. In all biopsies, vascular smooth muscle cells also stained and served as important intrinsic controls, which showed that in MA samples when spermatogenesis was impaired, staining was restricted to only few peritubular cells or was absent. When spermatogenesis was normal, regular peritubular staining became obvious. This pattern suggests complex regulatory influences, which in face of the identical systemic hormonal situation in MA patients, are likely caused by the local testicular micromilieu. The PG metabolite 15dPGJ2 may represent such a factor and it reduced Cal protein levels in peritubular cells from patients with/without impaired spermatogenesis. The documented phenotypic switch of peritubular, smooth muscle-like cells in MA patients may impair the abilities of the afflicted seminiferous tubules to contract and relax and must now be considered as a part of the complex events in male infertility.
Collapse
Affiliation(s)
- H Welter
- Anatomy III - Cell Biology, Ludwig Maximilian University, Munich, Germany
| | | | | | | | | | | | | |
Collapse
|
6
|
Hochberg Z, Feil R, Constancia M, Fraga M, Junien C, Carel JC, Boileau P, Le Bouc Y, Deal CL, Lillycrop K, Scharfmann R, Sheppard A, Skinner M, Szyf M, Waterland RA, Waxman DJ, Whitelaw E, Ong K, Albertsson-Wikland K. Child health, developmental plasticity, and epigenetic programming. Endocr Rev 2011; 32:159-224. [PMID: 20971919 PMCID: PMC3365792 DOI: 10.1210/er.2009-0039] [Citation(s) in RCA: 401] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 08/27/2010] [Indexed: 11/19/2022]
Abstract
Plasticity in developmental programming has evolved in order to provide the best chances of survival and reproductive success to the organism under changing environments. Environmental conditions that are experienced in early life can profoundly influence human biology and long-term health. Developmental origins of health and disease and life-history transitions are purported to use placental, nutritional, and endocrine cues for setting long-term biological, mental, and behavioral strategies in response to local ecological and/or social conditions. The window of developmental plasticity extends from preconception to early childhood and involves epigenetic responses to environmental changes, which exert their effects during life-history phase transitions. These epigenetic responses influence development, cell- and tissue-specific gene expression, and sexual dimorphism, and, in exceptional cases, could be transmitted transgenerationally. Translational epigenetic research in child health is a reiterative process that ranges from research in the basic sciences, preclinical research, and pediatric clinical research. Identifying the epigenetic consequences of fetal programming creates potential applications in clinical practice: the development of epigenetic biomarkers for early diagnosis of disease, the ability to identify susceptible individuals at risk for adult diseases, and the development of novel preventive and curative measures that are based on diet and/or novel epigenetic drugs.
Collapse
Affiliation(s)
- Z Hochberg
- Rambam Medical Center, Rappaport Faculty of Medicine and Research Institute, Technion–Israel Institute of Technology, Haifa, Israel.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Abstract
To further our understanding of genomic imprinting it will be essential to identify key control elements, and to investigate their regulation by both epigenetic modifications (such as DNA methylation) and trans-acting factors. So far, sequence elements that regulate parental allele-specific gene expression have been identified in a number of imprinted loci, either because of their differential DNA methylation or through functional studies in transgenic mice (1,2). A systematic search for allele-specific chromatin features constitutes an alternative strategy to identify elements that regulate imprinting. The validity of such an in vivo chromatin approach derives from the fact that in several known imprinting control-elements, a specialized organization of chromatin characterized by nuclease hypersensitivity is present on only one of the two parental chromosome (3). For example, the differentially methylated 5 -portion of the human SNRPN gene-a sequence element that controls imprinting in the Prader-Willi and Angelman syndromes' domain on chromosome 15q11- q13-has strong DNase-I hypersensitive sites on the unmethylated paternal chromosome (4). A differentially methylated region that regulates the imprinting of H19 and that of the neighboring insulin-like growth factor-2 gene on mouse chromosome 7 was also found to have parental chromosome-specific hypersensitive sites (5,6). The precise nature of the allelic nuclease hypersensitivity in these and other imprinted loci remains to be determined in more detail, for example, by applying complementary chromatin methodologies (7,8). However, it is commonly observed that a nuclease hypersensitive site corresponds to a small region where nucleosomes are absent or partially disrupted.
Collapse
Affiliation(s)
- R I Gregory
- Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
| | | | | |
Collapse
|
8
|
Jawien J, Bian Z, Sheikine Y, Olofsson PS, Pang Y, Edholm T, Dou Y, Metzger D, Hellström PM, Feil R, Hansson GK. Abrogation of mitochondrial transcription in smooth muscle cells impairs smooth muscle contractility and vascular tone. J Physiol Pharmacol 2008; 59:239-252. [PMID: 18622043] [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] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 04/25/2008] [Indexed: 05/26/2023]
Abstract
BACKGROUND Smooth muscle cells (SMC) constitute the major contractile cell population of blood vessels and inner organs. SMC contraction depends on energy provided by adenosine triphosphate (ATP) catabolism, which can be generated through oxidative phosphorylation in mitochondria or by anaerobic glycolysis. Mitochondrial activity may also modulate smooth muscle tone by biotransformation of vasoactive mediators. Here, we study the role of mitochondrial DNA gene expression for vascular function in vivo. METHODS Since loss of functional mitochondria in SMC may not be compatible with normal development, we generated mice with inducible SMC-specific abrogation of the mitochondrial transcription factor A (Tfam). Deletion of this gene leads to dysfunctional mitochondria and prevents aerobic ATP production in affected cells. RESULTS Invasive blood pressure monitoring in live animals demonstrated that SMC specific Tfam deletion results in lower blood pressure and a defective blood-pressure response to stress, changes that were not compensated by increased heart rate. The contractility to agonists was reduced in arterial and gastric fundus strips from Tfam-deficient mice. Endothelium-dependent relaxation of arterial strips in response to ACh was also blunted. CONCLUSION Our data show that mitochondrial function is needed for normal gastric contraction, vascular tone, and maintenance of normal blood pressure.
Collapse
Affiliation(s)
- J Jawien
- Department of Medicine; Karolinska Institute, Stockholm, Sweden
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Lutz SZ, Hennige AM, Feil S, Feil R, Häring HU. Analyse der Insulinsignaltransduktion in einer cGMP-abhängigen Proteinkinase Typ I (cGKI)-defizienten Mauslinie. DIABETOL STOFFWECHS 2008. [DOI: 10.1055/s-2008-1076267] [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: 10/21/2022]
|
10
|
Abstract
In the last decade, site-specific recombinases (SSRs), such as Cre and Flp, have emerged as indispensable tools for the precise in vivo manipulation of the mouse genome. It is now feasible to control, in space and time, the onset of gene knockouts in almost any tissue of the mouse, thus greatly facilitating the creation of sophisticated animal models for human disease and drug development. This review describes the basic principles and current status of the SSR technology, with a focus on strategies for conditional somatic mutagenesis using the Cre/lox system and ligand-activated Cre recombinases. Practical hints for generating and analysing conditional mouse mutants will be given and exciting novel applications of the SSR technology will be discussed, such as cell fate mapping and the combined use of Cre, Flp and other biotechnological tools. It will be shown how genetic manipulation of the mouse by site-specific recombination can provide new solutions to old problems in the analysis of human physiology and pathophysiology and how it can be employed for drug discovery and development.
Collapse
Affiliation(s)
- R Feil
- Interfakultäres Institut für Biochemie, Universität Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany.
| |
Collapse
|
11
|
Rübberdt A, Feil R, Stengel D, Spranger N, Mutze S, Wich M, Ekkernkamp A. [The clinical use of the ISO-C(3D) imaging system in calcaneus fracture surgery]. Unfallchirurg 2006; 109:112-8. [PMID: 16437245 DOI: 10.1007/s00113-005-1015-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [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: 11/24/2022]
Abstract
We compared in a prospective study including 82 patients treated with ORIF of an intraarticular calcaneus fracture the quality of fluoroscopy, intraoperatively Iso-C(3D) and postoperative CT-scans. Therefore the posterior facet of the calcaneus (PFOC) was divided into three sectors. Joint steps and fracture gaps were detected by two independent investigators and statistically analysed. Another focus was to evaluate if the findings due to intraoperatively Iso-C(3D) assessment performed by the surgeon were correct and subsequently influenced the surgical procedure. There were no statistically differences between the Iso-C(3D)- and CT findings concerning joint steps or fracture gaps in PFOC sectors I-III. With fluoroscopy an assessment of the PFOC sectors I and II was not possible. In six cases (7.3%), intraoperative reduction was redone after performing an Iso-C(3D) scan. In ten cases, 12 malpositioned screws were replaced (12.2%/14.6%). These results suggest that intraoperative 3D Iso-C(3D) imaging provides a high diagnostic reliability. By careful assessment of the images the surgeons receive information which could lead to a change of the operative strategy.
Collapse
Affiliation(s)
- A Rübberdt
- Klinik für Unfall- und Wiederherstellungschirurgie, Unfallkrankenhaus, Berlin.
| | | | | | | | | | | | | |
Collapse
|
12
|
Boesten LSM, Zadelaar SM, De Clercq S, Francoz S, van Nieuwkoop A, Biessen EAL, Hofmann F, Feil S, Feil R, Jochemsen AG, Zurcher C, Havekes LM, van Vlijmen BJM, Marine JC. Mdm2, but not Mdm4, protects terminally differentiated smooth muscle cells from p53-mediated caspase-3-independent cell death. Cell Death Differ 2006; 13:2089-98. [PMID: 16729027 DOI: 10.1038/sj.cdd.4401973] [Citation(s) in RCA: 48] [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: 11/08/2022] Open
Abstract
p53 is a potent inhibitor of cell growth and an inducer of apoptosis. During embryonic development, Mdm2 and Mdm4 inhibit the growth suppressive activities of p53. However, whether tight surveillance of p53 activity is required in quiescent cells is unknown. To test this, conditional inactivation of mdm2 and mdm4 was carried out in smooth muscle cells (SMCs). Upon SMC-specific inactivation of mdm2, and not of mdm4, mice rapidly became ill and died. Necropsy showed small intestinal dilation, and histological analyses indicated a severe reduction in the number of intestinal SMCs. Increased p53 levels and activity were detected in the remaining SMCs, and the phenotype was completely rescued on a p53-null background. Interestingly, intestinal SMCs are caspase-3-negative and therefore did not undergo caspase-3-dependent apoptotic cell death. Together, Mdm2, but not Mdm4, prevents accumulation of active p53 in quiescent SMCs and thereby the induction of p53-mediated caspase-3-independent cell death.
Collapse
Affiliation(s)
- L S M Boesten
- Department of General Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Monk D, Arnaud P, Apostolidou S, Hills FA, Kelsey G, Stanier P, Feil R, Moore GE. Limited evolutionary conservation of imprinting in the human placenta. Proc Natl Acad Sci U S A 2006; 103:6623-8. [PMID: 16614068 PMCID: PMC1564202 DOI: 10.1073/pnas.0511031103] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.2] [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: 02/04/2023] Open
Abstract
The epigenetic phenomenon of genomic imprinting provides an additional level of gene regulation that is confined to a limited number of genes, frequently, but not exclusively, important for embryonic development. The evolution and maintenance of imprinting has been linked to the balance between the allocation of maternal resources to the developing fetus and the mother's well being. Genes that are imprinted in both the embryo and extraembryonic tissues show extensive conservation between a mouse and a human. Here we examine the human orthologues of mouse genes imprinted only in the placenta, assaying allele-specific expression and epigenetic modifications. The genes from the KCNQ1 domain and the isolated human orthologues of the imprinted genes Gatm and Dcn all are expressed biallelically in the human, from first-trimester trophoblast through to term. This lack of imprinting is independent of promoter CpG methylation and correlates with the absence of the allelic histone modifications dimethylation of lysine-9 residue of H3 (H3K9me2) and trimethylation of lysine-27 residue of H3 (H3K27me3). These specific histone modifications are thought to contribute toward regulation of imprinting in the mouse. Genes from the IGF2R domain show polymorphic concordant expression in the placenta, with imprinting demonstrated in only a minority of samples. Together these findings have important implications for understanding the evolution of mammalian genomic imprinting. Because most human pregnancies are singletons, this absence of competition might explain the comparatively relaxed need in the human for placental-specific imprinting.
Collapse
Affiliation(s)
- D Monk
- Institute of Reproductive and Developmental Biology, Imperial College London, London W12 0NN, United Kingdom.
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Abstract
Genomic imprinting is an epigenetic mechanism that is important for the development and function of the extra-embryonic tissues in the mouse. Remarkably all the autosomal genes which were found to be imprinted in the trophoblast (placenta) only are active on the maternal and repressed on the paternal allele. It was shown for several of these genes that their paternal silencing is not dependent on DNA methylation, at least not in its somatic maintenance. Rather, recent studies in the mouse suggest that placenta-specific imprinting involves repressive histone modifications and non-coding RNAs. This mechanism of autosomal imprinting is similar to imprinted X chromosome inactivation in the placenta. Although the underlying reasons remain to be explored, this suggests that imprinting in the placenta and imprinted X inactivation are evolutionarily related.
Collapse
Affiliation(s)
- A Wagschal
- Institute of Molecular Genetics, CNRS and University of Montpellier II, Montpellier, France
| | | |
Collapse
|
15
|
Abstract
Over the past few years, a wealth of biochemical and functional data have been gathered on mammalian cGMP-dependent protein kinases (cGKs). In mammals, three different kinases are encoded by two genes. Mutant and chimeric cGK proteins generated by molecular biology techniques yielded important biochemical knowledge, such as the function of the NH2-terminal domains of cGKI and cGKII, the identity of the cGMP-binding sites of cGKI, and the substrate specificity of the enzymes. Genetic approaches have proven especially useful for the analysis of the biological functions of cGKs. Recently, some of the in vivo targets and mechanisms leading to changes in neuronal adaptation, smooth muscle relaxation and growth, intestinal water secretion, bone growth, renin secretion, and other important functions have been identified. These data show that cGKs are signaling molecules involved in many biological functions.
Collapse
Affiliation(s)
- F Hofmann
- Institut für Pharmakologie und Toxicologie, Technische Universität München, Biedersteiner Strasse 29, D-80802 Munich, Germany.
| | | | | | | |
Collapse
|
16
|
Feil S, Zimmermann P, Knorn A, Brummer S, Schlossmann J, Hofmann F, Feil R. Distribution of cGMP-dependent protein kinase type I and its isoforms in the mouse brain and retina. Neuroscience 2005; 135:863-8. [PMID: 16154279 DOI: 10.1016/j.neuroscience.2005.06.051] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [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: 04/17/2005] [Revised: 06/19/2005] [Accepted: 06/22/2005] [Indexed: 11/22/2022]
Abstract
Nitric oxide (NO) modulates a variety of processes in the mammalian brain, but the mechanisms of neuronal NO signaling are poorly understood. In the periphery, many effects of NO are mediated via the generation of the second messenger cyclic guanosine-3',5'-monophosphate (cGMP) and activation of the cGMP-dependent protein kinase type I (cGKI). However, previous studies suggested that the expression of cGKI in the nervous system is rather restricted, thus, questioning the functional significance of the cGMP/cGKI pathway as a mediator of NO signaling in the brain. Here we have performed a detailed immunohistochemical study to elucidate the distribution of cGKI in the CNS and eye of the mouse. Expression of cGKI protein was detected not only in the previously described areas (cerebellum, hippocampus, dorsomedial hypothalamus) but also in a number of additional regions, such as medulla, subcommissural organ, cerebral cortex, amygdala, habenulae, various hypothalamic regions, olfactory bulb, pituitary gland, and retina. Immunoblotting with isoform-specific antibodies indicated that the cGKIalpha isoform is prominent in the cerebellum and medulla, whereas the cGKIbeta isoform is predominant in the cortex, hippocampus, hypothalamus, and olfactory bulb. Similar levels of the isoforms were detected in the pituitary gland and eye. Thus, it appears that distinct brain regions express distinct cGKI isoforms that signal via distinct pathways. Together, these results improve our understanding of the cellular and molecular mechanisms of NO/cGMP/cGKI signaling and indicate that the distribution and functional relevance of this pathway in the mammalian brain is broader than previously thought.
Collapse
Affiliation(s)
- S Feil
- Institut für Pharmakologie und Toxikologie der Technischen Universität München, Biedersteiner Strasse 29, 80802 München, Germany.
| | | | | | | | | | | | | |
Collapse
|
17
|
Sausbier M, Hu H, Arntz C, Feil S, Kamm S, Adelsberger H, Sausbier U, Sailer CA, Feil R, Hofmann F, Korth M, Shipston MJ, Knaus HG, Wolfer DP, Pedroarena CM, Storm JF, Ruth P. Cerebellar ataxia and Purkinje cell dysfunction caused by Ca2+-activated K+ channel deficiency. Proc Natl Acad Sci U S A 2004; 101:9474-8. [PMID: 15194823 PMCID: PMC439001 DOI: 10.1073/pnas.0401702101] [Citation(s) in RCA: 317] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Accepted: 05/11/2004] [Indexed: 11/18/2022] Open
Abstract
Malfunctions of potassium channels are increasingly implicated as causes of neurological disorders. However, the functional roles of the large-conductance voltage- and Ca(2+)-activated K(+) channel (BK channel), a unique calcium, and voltage-activated potassium channel type have remained elusive. Here we report that mice lacking BK channels (BK(-/-)) show cerebellar dysfunction in the form of abnormal conditioned eye-blink reflex, abnormal locomotion and pronounced deficiency in motor coordination, which are likely consequences of cerebellar learning deficiency. At the cellular level, the BK(-/-) mice showed a dramatic reduction in spontaneous activity of the BK(-/-) cerebellar Purkinje neurons, which generate the sole output of the cerebellar cortex and, in addition, enhanced short-term depression at the only output synapses of the cerebellar cortex, in the deep cerebellar nuclei. The impairing cellular effects caused by the lack of postsynaptic BK channels were found to be due to depolarization-induced inactivation of the action potential mechanism. These results identify previously unknown roles of potassium channels in mammalian cerebellar function and motor control. In addition, they provide a previously undescribed animal model of cerebellar ataxia.
Collapse
Affiliation(s)
- M Sausbier
- Pharmakologie und Toxikologie, Pharmazeutisches Institut, Universitat Tübingen, D-72076 Tuebingen, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Goto Y, Gomez M, Brockdorff N, Feil R. Differential patterns of histone methylation and acetylation distinguish active and repressed alleles at X-linked genes. Cytogenet Genome Res 2004; 99:66-74. [PMID: 12900547 DOI: 10.1159/000071576] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [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: 11/20/2002] [Accepted: 02/06/2003] [Indexed: 11/19/2022] Open
Abstract
In female mammals, one of the two X chromosomes is inactivated to compensate for the difference in dosage of X-linked genes between males and females. X inactivation involves sequential alterations to the chromatin that ultimately lead to the transcriptional repression of genes on the X chromosome. Here, histone methylation and acetylation along X-linked genes are investigated by chromatin immunoprecipitation (ChIP) of adult fibroblast cell lines. At PGK1 and HPRT, chromatin on the active X chromosome reveals H3 lysine 4 methylation and acetylation of histones H3 and H4. These modifications are absent on the repressed allele, which is marked by H3 lysine 9 methylation. On the expressed allele of XIST (on the inactive X chromosome), we found that H3 acetylation is confined to the promoter, whereas H3 lysine 4 methylation and H4 acetylation are present along the entire gene. On the repressed XIST allele, in contrast, the promoter and gene exhibit H3 lysine 9 methylation. At only 1.5 kb upstream of the XIST gene, chromatin on the inactive X chromosome has strongly reduced levels of H4 acetylation and is marked by both H3 lysine 9 and H3 lysine 4 methylation. These data demonstrate that patterns of histone methylation and acetylation are distinct along and upstream of XIST and suggest that the inactive X chromatin configuration occurs at a region close to the 5' end of the gene.
Collapse
Affiliation(s)
- Y Goto
- Institute of Molecular Genetics, CNRS, Montpellier, France
| | | | | | | |
Collapse
|
19
|
Reik W, Murrell A, Lewis A, Mitsuya K, Umlauf D, Dean W, Higgins M, Feil R. Chromosome loops, insulators, and histone methylation: new insights into regulation of imprinting in clusters. Cold Spring Harb Symp Quant Biol 2004; 69:29-37. [PMID: 16117630 DOI: 10.1101/sqb.2004.69.29] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- W Reik
- Laboratory of Developmental Genetics and Imprinting, The Babraham Institute, Cambridge CB2 4AT, United Kingdom.
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Gregory RI, Randall TE, Johnson CA, Khosla S, Hatada I, O'Neill LP, Turner BM, Feil R. DNA methylation is linked to deacetylation of histone H3, but not H4, on the imprinted genes Snrpn and U2af1-rs1. Mol Cell Biol 2001; 21:5426-36. [PMID: 11463825 PMCID: PMC87265 DOI: 10.1128/mcb.21.16.5426-5436.2001] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [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: 11/20/2022] Open
Abstract
The relationship between DNA methylation and histone acetylation at the imprinted mouse genes U2af1-rs1 and Snrpn is explored by chromatin immunoprecipitation (ChIP) and resolution of parental alleles using single-strand conformational polymorphisms. The U2af1-rs1 gene lies within a differentially methylated region (DMR), while Snrpn has a 5' DMR (DMR1) with sequences homologous to the imprinting control center of the Prader-Willi/Angelman region. For both DMR1 of Snrpn and the 5' untranslated region (5'-UTR) and 3'-UTR of U2af1-rs1, the methylated and nonexpressed maternal allele was underacetylated, relative to the paternal allele, at all H3 lysines tested (K14, K9, and K18). For H4, underacetylation of the maternal allele was exclusively (U2af1-rs1) or predominantly (Snrpn) at lysine 5. Essentially the same patterns of differential acetylation were found in embryonic stem (ES) cells, embryo fibroblasts, and adult liver from F1 mice and in ES cells from mice that were dipaternal or dimaternal for U2af1-rs1. In contrast, in a region within Snrpn that has biallelic methylation in the cells and tissues analyzed, the paternal (expressed) allele showed relatively increased acetylation of H4 but not of H3. The methyl-CpG-binding-domain (MBD) protein MeCP2 was found, by ChIP, to be associated exclusively with the maternal U2af1-rs1 allele. To ask whether DNA methylation is associated with histone deacetylation, we produced mice with transgene-induced methylation at the paternal allele of U2af1-rs1. In these mice, H3 was underacetylated across both the parental U2af1-rs1 alleles whereas H4 acetylation was unaltered. Collectively, these data are consistent with the hypothesis that CpG methylation leads to deacetylation of histone H3, but not H4, through a process that involves selective binding of MBD proteins.
Collapse
Affiliation(s)
- R I Gregory
- Programme in Developmental Genetics, The Babraham Institute, Cambridge CB2 4AT, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Abstract
A growing number of medical, scientific and biotechnological procedures rely on culture of mammalian preimplantation embryos. This review presents currently available data on aberrant offspring development that sometimes arises from commonly applied in-vitro procedures in humans, ruminant species and mice. Comparison between mammalian species reveals similarities in the phenotypic abnormalities that are observed at fetal and perinatal stages of development. In particular, aberrant effects on fetal growth have been observed in multiple studies in which serum complemented the preimplantation culture medium. Although it remains to be determined whether there is a common causal mechanism(s) involved, several hypotheses have been put forward to account for the variety of the observed developmental abnormalities. One of these postulates that culture can result in the epigenetic deregulation of developmentally important genes, and that such epigenetic alterations would affect in particular the expression of genes that are subject to genomic imprinting. Imprinted genes play key roles in the control of fetal growth, and altered imprinting can cause growth defects. Some recent in-vitro culture studies on mice and ruminant species now lend support to this hypothesis.
Collapse
Affiliation(s)
- S Khosla
- Programme in Developmental Genetics, The Babraham Institute, Cambridge, UK
| | | | | | | |
Collapse
|
22
|
|
23
|
Abstract
Genomic imprinting is an epigenetic marking mechanism by which certain genes become repressed on one of the two parental alleles. Imprinting plays important roles in mammalian development, and in humans its deregulation may result in disease and carcinogenesis. During different medical, technological and scientific interventions, pre-implantation embryos and cells are taken from their natural environment and subjected to culture in artificial media. Studies in the mouse demonstrate that environmental stress, such as in vitro culture, can affect the somatic maintenance of epigenetic marks at imprinted loci. These effects are associated with aberrant growth and morphology at fetal and perinatal stages of development.
Collapse
Affiliation(s)
- S L Thompson
- Programme in Developmental Genetics, The Babraham Institute, CB2 4AT, Cambridge, UK
| | | | | | | | | | | |
Collapse
|
24
|
Khosla S, Dean W, Brown D, Reik W, Feil R. Culture of preimplantation mouse embryos affects fetal development and the expression of imprinted genes. Biol Reprod 2001; 64:918-26. [PMID: 11207209 DOI: 10.1095/biolreprod64.3.918] [Citation(s) in RCA: 447] [Impact Index Per Article: 19.4] [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: 11/01/2022] Open
Abstract
Culture of preimplantation mammalian embryos and cells can influence their subsequent growth and differentiation. Previously, we reported that culture of mouse embryonic stem cells is associated with deregulation of genomic imprinting and affects the potential for these cells to develop into normal fetuses. The purpose of our current study was to determine whether culture of preimplantation mouse embryos in a chemically defined medium (M16) with or without fetal calf serum (FCS) can affect their subsequent development and imprinted gene expression. Only one third of the blastocysts that had been cultured from two-cell embryos in M16 medium complemented with FCS developed into viable Day 14 fetuses after transfer into recipients. These M16 + FCS fetuses were reduced in weight as compared with controls and M16 fetuses and had decreased expression of the imprinted H19 and insulin-like growth factor 2 genes associated with a gain of DNA methylation at an imprinting control region upstream of H19. They also displayed increased expression of the imprinted gene Grb10. The growth factor receptor binding gene Grb7, in contrast, was strongly reduced in its expression in most of the M16 + FCS fetuses. No alterations were detected for the imprinted gene MEST: Preimplantation culture in the presence of serum can influence the regulation of multiple growth-related imprinted genes, thus leading to aberrant fetal growth and development.
Collapse
Affiliation(s)
- S Khosla
- Laboratory of Developmental Genetics and Imprinting and Laboratory of Computational Neuroscience, The Babraham Institute, Babraham, Cambridge CB2 4AT, United Kingdom
| | | | | | | | | |
Collapse
|
25
|
Seisenberger C, Specht V, Welling A, Platzer J, Pfeifer A, Kühbandner S, Striessnig J, Klugbauer N, Feil R, Hofmann F. Functional embryonic cardiomyocytes after disruption of the L-type alpha1C (Cav1.2) calcium channel gene in the mouse. J Biol Chem 2000; 275:39193-9. [PMID: 10973973 DOI: 10.1074/jbc.m006467200] [Citation(s) in RCA: 198] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The L-type alpha(1C) (Ca(v)1.2) calcium channel is the major calcium entry pathway in cardiac and smooth muscle. We inactivated the Ca(v)1.2 gene in two independent mouse lines that had indistinguishable phenotypes. Homozygous knockout embryos (Ca(v)1. 2-/-) died before day 14.5 postcoitum (p.c.). At day 12.5 p.c., the embryonic heart contracted with identical frequency in wild type (+/+), heterozygous (+/-), and homozygous (-/-) Ca(v)1.2 embryos. Beating of isolated embryonic cardiomyocytes depended on extracellular calcium and was blocked by 1 microm nisoldipine. In (+/+), (+/-), and (-/-) cardiomyocytes, an L-type Ba(2+) inward current (I(Ba)) was present that was stimulated by Bay K 8644 in all genotypes. At a holding potential of -80 mV, nisoldipine blocked I(Ba) of day 12.5 p.c. (+/+) and (+/-) cells with two IC(50) values of approximately 0.1 and approximately 1 microm. Inhibition of I(Ba) of (-/-) cardiomyocytes was monophasic with an IC(50) of approximately 1 microm. The low affinity I(Ba) was also present in cardiomyocytes of homozygous alpha(1D) (Ca(v)1.3) knockout embryos at day 12.5 p.c. These results indicate that, up to day 14 p.c., contraction of murine embryonic hearts requires an unidentified, low affinity L-type like calcium channel.
Collapse
MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Barium/metabolism
- Calcium Channel Agonists/pharmacology
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/physiology
- Cell Line
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Electrophysiology
- Exons
- Genetic Vectors
- Genotype
- Heart/embryology
- Homozygote
- Inhibitory Concentration 50
- Ions
- Kinetics
- Mice
- Mice, Knockout
- Models, Genetic
- Myocardium/cytology
- Nisoldipine/pharmacology
- Phenotype
- RNA/metabolism
- Time Factors
Collapse
Affiliation(s)
- C Seisenberger
- Institut für Pharmakologie und Toxikologie, TU München, Biedersteiner Strasse 29, D-80802 München, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Hansen RS, Stöger R, Wijmenga C, Stanek AM, Canfield TK, Luo P, Matarazzo MR, D'Esposito M, Feil R, Gimelli G, Weemaes CM, Laird CD, Gartler SM. Escape from gene silencing in ICF syndrome: evidence for advanced replication time as a major determinant. Hum Mol Genet 2000; 9:2575-87. [PMID: 11063717 DOI: 10.1093/hmg/9.18.2575] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.7] [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: 11/14/2022] Open
Abstract
Chromosomal abnormalities associated with hypomethylation of classical satellite regions are characteristic for the ICF immunodeficiency syndrome. We, as well as others, have found that these effects derive from mutations in the DNMT3B DNA methyltransferase gene. Here we examine further the molecular phenotype of ICF cells and report several examples of extensive hypomethylation that are associated with advanced replication time, nuclease hypersensitivity and a variable escape from silencing for genes on the inactive X and Y chromosomes. Our analysis suggests that all genes on the inactive X chromosome may be extremely hypomethylated at their 5' CpG islands. Our studies of G6PD in one ICF female and SYBL1 in another ICF female provide the first examples of abnormal escape from X chromosome inactivation in untransformed human fibroblasts. XIST RNA localization is normal in these cells, arguing against an independent silencing role for this RNA in somatic cells. SYBL1 silencing is also disrupted on the Y chromosome in ICF male cells. Increased chromatin sensitivity to nuclease was found at all hypomethylated promoters examined, including those of silenced genes. The persistence of inactivation in these latter cases appears to depend critically on delayed replication of DNA because escape from silencing was only seen when replication was advanced to an active X-like pattern.
Collapse
Affiliation(s)
- R S Hansen
- Department of Medicine, Box 357360, University of Washington, Seattle, WA 98195, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Schurr U, Heckenberger U, Herdel K, Walter A, Feil R. Leaf development in Ricinus communis during drought stress: dynamics of growth processes, of cellular structure and of sink-source transition. J Exp Bot 2000; 51:1515-1529. [PMID: 11006303 DOI: 10.1093/jexbot/51.350.1515] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [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
Dicot leaf growth is characterized by partly transient tip-to-base gradients of growth processes, structure and function. These gradients develop dynamically and interact with dynamically developing stress conditions like drought. In Ricinus communis plants growing under well-watered and drought conditions growth rates peaked during the late night and minimal values occurred in the late afternoon. During this diurnal course the leaf base always showed much higher rates than the leaf tip. The amplitude of this diurnal course decreased when leaves approached maturity and during drought stress without any significant alteration of the diurnal pattern and it increased during the first days after rewatering. Unique relationships between leaf size and cytological structure were observed. This provided the framework for the analysis of changes in assimilation, transpiration and dark respiration, chlorophyll, protein, carbohydrate, and amino acid concentrations, and of activities of sink-source-related enzymes at the leaf tip and base during leaf development in well-watered and drought-stressed plants. Gas exchange was dominated by physiological rather than by anatomical properties (stomatal density). Tip-to-base gradients in carbohydrate concentrations per dry weight and sink-source-related enzymes were absent, whereas significant gradients were found in amino acid concentrations per dry weight. During drought stress, growing leaves developed source function at smaller leaf size, before specific physiological adaptations to drought occurred. The relevance of the developmental status of individual leaves for the drought-stress response and of the structural changes for the biochemical composition changes is discussed.
Collapse
Affiliation(s)
- U Schurr
- Department of Botany, University of Heidelberg, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany.
| | | | | | | | | |
Collapse
|
28
|
Abstract
Ligand-dependent site-specific recombinases are powerful tools to engineer the mouse genome in specific somatic cell types at selected times during pre- and postnatal development. Current efforts are primarily directed towards increasing the efficiency of this recombination system in mice. We have generated transgenic mouse lines expressing a tamoxifen-activated Cre recombinase, CreER(T2), under the control of the smooth muscle-specific SM22 promoter. Both a randomly integrated transgene [SM-CreER(T2)(tg)] and a transgene that has been "knocked in" into the endogenous SM22 locus [SM-CreER(T2)(ki)] were expressed in smooth muscle-containing tissues. The level of CreER(T2) expression and tamoxifen-induced recombination was lower in SM-CreER(T2)(tg) mice compared with SM-CreER(T2)(ki) mice. Whereas no recombinase activity could be detected in vehicle-treated SM-CreER(T2)(ki) mice, administration of tamoxifen induced the excision of a loxP-flanked reporter transgene in up to 100% of smooth muscle cells. The recombined genome persisted for at least four months after tamoxifen treatment. SM-CreER(T2)(ki) transgenic mice should be useful to study the effects of various somatic mutations in smooth muscle.
Collapse
MESH Headings
- Animals
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/genetics
- Gene Targeting
- Injections, Intraperitoneal
- Integrases/biosynthesis
- Integrases/genetics
- Integrases/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Microfilament Proteins
- Muscle Proteins/genetics
- Muscle, Smooth/drug effects
- Muscle, Smooth/physiology
- Mutagenesis, Insertional/drug effects
- Mutagenesis, Insertional/genetics
- Organ Specificity/genetics
- Promoter Regions, Genetic/physiology
- RNA, Messenger/biosynthesis
- Receptors, Estrogen/genetics
- Receptors, Estrogen/physiology
- Recombination, Genetic/drug effects
- Tamoxifen/administration & dosage
- Transgenes/drug effects
- Transgenes/physiology
- Viral Proteins
Collapse
Affiliation(s)
- S Kühbandner
- Institut für Pharmakologie und Toxikologie, Technische Universität München, München, Germany
| | | | | | | | | | | |
Collapse
|
29
|
Reik W, Constancia M, Dean W, Davies K, Bowden L, Murrell A, Feil R, Walter J, Kelsey G. Igf2 imprinting in development and disease. Int J Dev Biol 2000; 44:145-50. [PMID: 10761859] [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] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Igf2 is one of the first imprinted genes discovered and occupies a centre stage in the study of imprinting. This is because it has dramatic effects on the control of fetal growth, it is involved in growth disorders and in cancer, it interacts with products of other imprinted genes, and its imprinting status is under complex regulation in a cluster of tightly linked imprinted genes. Here we review briefly the key features of Igf2 imprinting in normal development and in disease, and hope to show what a fascinating subject of study this gene and its biology provides.
Collapse
Affiliation(s)
- W Reik
- Developmental Genetics Programme, The Babraham Institute, Cambridge, United Kingdom.
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Abstract
Chromatin can be analysed by assaying its sensitivity to DNase I or other nucleases in purified nuclei. Usually, this is performed by Southern analysis of genomic DNA extracted from nuclease-treated nuclei, a methodology that requires many cells. Applying restriction fragment length polymorphisms (RFLPs), this methodology has been used for parental allele-specific chromatin studies on imprinted mammalian genes. However, such allelic studies are limited by the availability of suitable RFLPs. We therefore developed an alternative, PCR and single strand conformation polymorphism (SSCP)-based assay with which allelic sensitivity to nucleases can be determined in virtually all localised regions that have nucleotide polymorphisms. We also demonstrate that analysis of DNase I sensitivity can be performed on permeabilised cells. Combining the two approaches, in the imprinted mouse U2af1-rs1 gene we analysed parental allele-specific chromatin conformation in limited numbers of cultured cells. We also applied the PCR-SSCP approach to assay allelic DNA methylation at specific restriction enzyme sites. In summary, we developed an allele-specific assay that should be useful for biochemical and developmental investigation of chromatin, in particular for studies on genomic imprinting and X-chromosome inactivation.
Collapse
Affiliation(s)
- R I Gregory
- Programme in Developmental Genetics, The Babraham Institute, Cambridge CB2 4AT, UK
| | | |
Collapse
|
31
|
Abstract
Most imprinted loci have key regulatory elements that are methylated on only one of the parental chromosomes. For several of these 'differentially methylated regions', recent studies establish that the unmethylated chromosome has a specialized chromatin organization that is characterized by nuclease hypersensitivity. The novel data raise the question of whether specific proteins and associated chromatin features regulate the allele-specificity of DNA methylation at these imprinting control elements.
Collapse
Affiliation(s)
- R Feil
- Programme in Developmental Genetics, The Babraham Institute, Cambridge, UK CB2 4AT.
| | | |
Collapse
|
32
|
Gregory RI, Feil R. Analysis of chromatin in limited numbers of cells: a PCR-SSCP based assay of allele-specific nuclease sensitivity. Nucleic Acids Res 1999. [DOI: 10.1093/nar/27.22.e32-i] [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: 11/13/2022] Open
|
33
|
Abstract
Site-specific recombination systems are powerful tools for introducing predetermined modifications into eukaryotic genomes. Recent advances allow the manipulation of chromosomal DNA in a spatially and temporally controlled manner in mice, offering unprecedented possibilities for studying mammalian genome function and for generating animal models for human diseases.
Collapse
Affiliation(s)
- D Metzger
- Institut de Génétique et de Biologie Moléculaire et Cellulaire CNRS/INSERM/ULP Collége de France BP 163, 67404, Illkirch Cedex, CU de Strasbourg, France.
| | | |
Collapse
|
34
|
Khosla S, Aitchison A, Gregory R, Allen ND, Feil R. Parental allele-specific chromatin configuration in a boundary-imprinting-control element upstream of the mouse H19 gene. Mol Cell Biol 1999; 19:2556-66. [PMID: 10082521 PMCID: PMC84048 DOI: 10.1128/mcb.19.4.2556] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [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] Open
Abstract
The mouse H19 gene is expressed from the maternal chromosome exclusively. A 2-kb region at 2 to 4 kb upstream of H19 is paternally methylated throughout development, and these sequences are necessary for the imprinted expression of both H19 and the 5'-neighboring Igf2 gene. In particular, on the maternal chromosome this element appears to insulate the Igf2 gene from enhancers located downstream of H19. We analyzed the chromatin organization of this element by assaying its sensitivity to nucleases in nuclei. Six DNase I hypersensitive sites (HS sites) were detected on the unmethylated maternal chromosome exclusively, the two most prominent of which mapped 2.25 and 2.75 kb 5' to the H19 transcription initiation site. Five of the maternal HS sites were present in expressing and nonexpressing tissues and in embryonic stem (ES) cells. They seem, therefore, to reflect the maternal origin of the chromosome rather than the expression of H19. A sixth maternal HS site, at 3.45 kb upstream of H19, was detected in ES cells only. The nucleosomal organization of this element was analyzed in tissues and ES cells by micrococcal nuclease digestion. Specifically on the maternal chromosome, an unusual and strong banding pattern was obtained, suggestive of a nonnucleosomal organization. From our studies, it appears that the unusual chromatin organization with the presence of HS sites (maternal chromosome) and DNA methylation (paternal chromosome) in this element are mutually exclusive and reflect alternate epigenetic states. In addition, our data suggest that nonhistone proteins are associated with the maternal chromosome and that these might be involved in its boundary function.
Collapse
Affiliation(s)
- S Khosla
- Programme in Developmental Genetics, The Babraham Institute, Cambridge CB2 4AT, United Kingdom
| | | | | | | | | |
Collapse
|
35
|
Abstract
Studies in the mouse have established that both parental genomes are essential for normal embryonic development. Parthenogenetic mouse embryos (which have two maternal genomes and no paternal genome), for example, are growth-retarded and die at early postimplantation stages. The distinct maternal and paternal contributions are mediated by genomic imprinting, an epigenetic mechanism by which the expression of certain genes is dependent on whether they are inherited from mother or father. Although comparative studies have established that many imprinted mouse (and rat) genes are allele-specifically expressed in humans as well (and vice versa), so far imprinting studies have not been performed in other mammalian species. When considering evolutionary theories of genomic imprinting, it would be important to know how widely it is conserved among placental mammals. We have investigated its conservation in a bovid ruminant, the domestic sheep, by comparing parthenogenetic and normal control embryos. Our study establishes that, like in the mouse, parthenogenetic development in sheep is associated with growth-retardation and does not proceed beyond early fetal stages. These developmental abnormalities are most likely caused by imprinted genes. We demonstrate that, indeed, like in mice and humans, the growth-related PEG1/MEST and Insulin-like Growth Factor 2 (IGF2) genes are expressed from the paternal chromosome in sheep. These observations suggest that genomic imprinting is conserved in a third, evolutionarily rather diverged group of placental mammals, the ruminants.
Collapse
Affiliation(s)
- R Feil
- Programme in Developmental Genetics, The Babraham Institute, Cambridge CB2 4AT, United Kingdom
| | | | | | | |
Collapse
|
36
|
Brocard J, Feil R, Chambon P, Metzger D. A chimeric Cre recombinase inducible by synthetic,but not by natural ligands of the glucocorticoid receptor. Nucleic Acids Res 1998; 26:4086-90. [PMID: 9705523 PMCID: PMC147795 DOI: 10.1093/nar/26.17.4086] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [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: 11/12/2022] Open
Abstract
We have developed a new ligand-dependent chimeric recombinase (Cre-GRdex) by fusing the site-specific Cre recombinase to the ligand binding domain (LBD) of a mutant human glucocorticoid receptor (GRdex). The synthetic glucocorticoid receptor (GR) ligands dexamethasone, triamcinolone acetonide and RU38486efficiently induce recombinase activity in F9 murine embryonal carcinoma cells expressing constitutively Cre-GRdex. In contrast, no recombinase activity was detected in the absence of ligand or in the presence of the natural GR ligands corticosterone, cortisol or aldosterone. Moreover, physiological concentrations of these natural GR ligands do not affect Cre-GRdexrecombinase activity induced by dexamethasone. Thus, as previously shown using Cre-oestrogen receptor (ER) fusion proteins, Cre-GRdexmight be useful for achieving loxP site-directed mutagenesis in cultured cells and spatio-temporally controlled somatic cell mutagenesis in transgenic mice.
Collapse
Affiliation(s)
- J Brocard
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Collège de France, BP 163,67404 Illkirch Cedex, C. U. de Strasbourg, France
| | | | | | | |
Collapse
|
37
|
Dean W, Bowden L, Aitchison A, Klose J, Moore T, Meneses JJ, Reik W, Feil R. Altered imprinted gene methylation and expression in completely ES cell-derived mouse fetuses: association with aberrant phenotypes. Development 1998; 125:2273-82. [PMID: 9584126 DOI: 10.1242/dev.125.12.2273] [Citation(s) in RCA: 286] [Impact Index Per Article: 11.0] [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: 11/20/2022]
Abstract
In vitro manipulation of preimplantation mammalian embryos can influence differentiation and growth at later stages of development. In the mouse, culture of embryonic stem (ES) cells affects their totipotency and may give rise to fetal abnormalities. To investigate whether this is associated with epigenetic alterations in imprinted genes, we analysed two maternally expressed genes (Igf2r, H19) and two paternally expressed genes (Igf2, U2af1-rs1) in ES cells and in completely ES cell-derived fetuses. Altered allelic methylation patterns were detected in all four genes, and these were consistently associated with allelic changes in gene expression. All the methylation changes that had arisen in the ES cells persisted on in vivo differentiation to fetal stages. Alterations included loss of methylation with biallelic expression of U2af1-rs1, maternal methylation and predominantly maternal expression of Igf2, and biallelic methylation and expression of Igf2r. In many of the ES fetuses, the levels of H19 expression were strongly reduced, and this biallelic repression was associated with biallellic methylation of the H19 upstream region. Surprisingly, biallelic H19 repression was not associated with equal levels of Igf2 expression from both parental chromosomes, but rather with a strong activation of the maternal Igf2 allele. ES fetuses derived from two of the four ES lines appeared developmentally compromised, with polyhydramnios, poor mandible development and interstitial bleeding and, in chimeric fetuses, the degree of chimerism correlated with increased fetal mass. Our study establishes a model for how early embryonic epigenetic alterations in imprinted genes persist to later developmental stages, and are associated with aberrant phenotypes.
Collapse
Affiliation(s)
- W Dean
- Laboratory of Developmental Genetics Programme, The Babraham Institute, Babraham Hall, Cambridge CB2 4AT, UK
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Affiliation(s)
- R Feil
- Department of Development and Genetics, Babraham Institute, Cambridge, United Kingdom.
| | | |
Collapse
|
39
|
Moore T, Constancia M, Zubair M, Bailleul B, Feil R, Sasaki H, Reik W. Multiple imprinted sense and antisense transcripts, differential methylation and tandem repeats in a putative imprinting control region upstream of mouse Igf2. Proc Natl Acad Sci U S A 1997; 94:12509-14. [PMID: 9356480 PMCID: PMC25020 DOI: 10.1073/pnas.94.23.12509] [Citation(s) in RCA: 204] [Impact Index Per Article: 7.6] [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: 02/05/2023] Open
Abstract
The mouse insulin-like growth factor 2 (Igf2) locus is a complex genomic region that produces multiple transcripts from alternative promoters. Expression at this locus is regulated by parental imprinting. However, despite the existence of putative imprinting control elements in the Igf2 upstream region, imprinted transcriptional repression is abolished by null mutations at the linked H19 locus. To clarify the extent to which the Igf2 upstream region contains autonomous imprinting control elements we have performed functional and comparative analyses of the region in the mouse and human. Here we report the existence of multiple, overlapping imprinted (maternally repressed) sense and antisense transcripts that are associated with a tandem repeat in the mouse Igf2 upstream region. Regions flanking the repeat exhibit tissue-specific parental allelic methylation patterns, suggesting the existence of tissue-specific control elements in the upstream region. Studies in H19 null mice indicate that both parental allelic methylation and monoallelic expression of the upstream transcripts depends on an intact H19 gene acting in cis. The homologous region in human IGF2 is structurally conserved, with the significant exception that it does not contain a tandem repeat. Our results support the proposal that tandem repeats act to target methylation to imprinted genetic loci.
Collapse
Affiliation(s)
- T Moore
- Department of Development and Genetics, The Babraham Institute, Cambridge CB2 4AT, United Kingdom.
| | | | | | | | | | | | | |
Collapse
|
40
|
Abstract
Ligand-dependent chimeric Cre recombinases are powerful tools to induce specific DNA rearrangements in cultured cells and in mice. We report here the construction and characterization of a series of chimeric recombinases, each consisting of Cre fused to a mutated human oestrogen receptor (ER) ligand-binding domain (LBD). Two new ligand-dependent recombinases which contain either the G400V/M543A/L544A or the G400V/L539A/L540A triple mutation of the human ER LBD are efficiently induced by the synthetic ER antagonists 4-hydroxytamoxifen (OHT) and ICI 182,780 (ICI), respectively, but are insensitive to 17 beta-oestradiol (E2). Both chimeric recombinases should be useful for efficient spatio-temporally controlled site-directed somatic mutagenesis.
Collapse
Affiliation(s)
- R Feil
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Collège de France, Illkirch, C.U. de Strasbourg, France
| | | | | | | |
Collapse
|
41
|
Abstract
The imprinted U2af1-rs1 gene on mouse chromosome 11 is expressed exclusively from the paternal allele. We found that U2af1-rs1 resides in a chromosomal domain that displays marked differences in chromatin conformation and DNA methylation between the parental chromosomes. Chromatin conformation was assayed in brain and liver, in fetuses, and in embryonic stem cells by sensitivity to nucleases in nuclei. In all these tissues, the unmethylated paternal chromosome is sensitive to DNase-I and MspI and has two DNase-I hypersensitive sites in the 5'-untranslated region. In brain and in differentiated stem cells, which display high levels of U2af1-rs1 expression, a paternal DNase-I hypersensitive site is also readily apparent in the promoter region. On the maternal chromosome, in contrast, the entire U2af1-rs1 gene and its promoter are highly resistant to DNase-I and MspI in all tissues analyzed and are fully methylated. No differential MNase sensitivity was detected in this imprinted domain. The parental chromosome-specific DNA methylation and chromatin conformation were also present in parthenogenetic and androgenetic cells and in tissues from animals maternally or paternally disomic for chromosome 11. This demonstrates that these parental chromosome-specific epigenotypes are independently established and maintained and provides no evidence for interallelic trans-sensing and counting mechanisms in U2af1-rs1.
Collapse
Affiliation(s)
- R Feil
- Department of Development and Genetics, the Babraham Institute, Cambridge CB2 4AT, United Kingdom.
| | | | | | | |
Collapse
|
42
|
Forné T, Feil R. Dérèglement de la voie des facteurs de croissance de type insuline dans les syndromes d'anomalie de croissance. Med Sci (Paris) 1997. [DOI: 10.4267/10608/443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
43
|
Sasaki H, Shimozaki K, Zubair M, Aoki N, Ohta K, Hatano N, Moore T, Feil R, Constancia M, Reik W, Rotwein P. Nucleotide sequence of a 28-kb mouse genomic region comprising the imprinted Igf2 gene. DNA Res 1996; 3:331-5. [PMID: 9039503 DOI: 10.1093/dnares/3.5.331] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [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: 02/03/2023] Open
Abstract
The mouse insulin-like growth factor II gene (Igf2) is physically linked to the insulin II gene (Ins2) and both are subject to tissue-specific genomic imprinting. The paternal-specific expression of Igf2 has been associated with hypermethylation of some CpG sites in the 5' flanking region and in the body of the gene. As a first step in analyzing the structural features of this imprinted locus, we here report the complete nucleotide sequence of Igf2, including all introns and the intergenic region adjacent to Ins2. This 28-kb segment of mouse chromosome 7 exhibits 80% overall identity with the corresponding rat sequence and has a high GC content of 52%. In addition to the known CpG island within the second Igf2 promoter, another island was identified approximately 2 kb 5' to the first exon. Other features of this locus include a 35-fold tandem repeat of an 11-bp sequence that overlaps Igf2 pseudo-exon 2, and a B2 repeat element in the intergenic region between Ins2 and Igf2. The GC-richness and the presence of CpG islands associated with tandem repeats are common features of imprinted genes and thus may play a role in the imprinting mechanism.
Collapse
Affiliation(s)
- H Sasaki
- Division of Disease Genes, Kyushu University, Fukuoka, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Abstract
Current mouse gene targeting technology is unable to introduce somatic mutations at a chosen time and/or in a given tissue. We report here that conditional site-specific recombination can be achieved in mice using a new version of the Cre/lox system. The Cre recombinase has been fused to a mutated ligand-binding domain of the human estrogen receptor (ER) resulting in a tamoxifen-dependent Cre recombinase, Cre-ERT, which is activated by tamoxifen, but not by estradiol. Transgenic mice were generated expressing Cre-ERT under the control of a cytomegalovirus promoter. We show that excision of a chromosomally integrated gene flanked by loxP sites can be induced by administration of tamoxifen to these transgenic mice, whereas no excision could be detected in untreated animals. This conditional site-specific recombination system should allow the analysis of knockout phenotypes that cannot be addressed by conventional gene targeting.
Collapse
Affiliation(s)
- R Feil
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université Louis Pasteur, Collège de France, C.U. de Strasbourg, France
| | | | | | | | | | | |
Collapse
|
45
|
Reik W, Bowden L, Constancia M, Dean W, Feil R, Forné T, Kelsey G, Maher E, Moore T, Sun FL, Walter J. Regulation of Igf2 imprinting in development and disease. Int J Dev Biol 1996; Suppl 1:53S-54S. [PMID: 9087693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- W Reik
- Laboratory of Developmental Genetics and Imprinting, Babraham Institute, Cambridge
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Abstract
The phosphorylation of threonine residues in the catalytic core of several protein kinases is important for the functional integrity of these enzymes. The corresponding residues of cGMP-dependent protein kinase I alpha (cGMP kinase) are Thr-514 and/or Thr-516. The in vivo phosphorylation and functional role of these residues was studied. cGMP kinase was overexpressed and purified as a catalytically active and inactive enzyme in Sf9 insect cells and in Escherichia coli, respectively. The enzymological and physicochemical properties of the Sf9 cGMP kinase were indistinguishable from that of the purified bovine lung enzyme. The cysteines of cGMP kinase including Cys-518 were labeled with vinylpyridine. Amino acid sequencing and mass spectroscopy of the labeled peptides showed that Thr-516 was phosphorylated in the enzyme purified from Sf9 cells but not in that from E. coli. The functional importance of phosphothreonine-516 was investigated by substitution of Thr-516 by alanine (T516A) or by glutamate (T516E). Expression in insect cells of the T516A mutant resulted in a protein lacking detectable kinase activity, whereas the T516E mutant retained basal phosphotransferase activity. In E. coli, the exchange of Thr-516 by glutamate did not lead to the synthesis of a catalytically active enzyme. These results demonstrate that phosphothreonine-516 of cGMP kinase is crucial for the formation of an enzymatically active protein kinase.
Collapse
Affiliation(s)
- R Feil
- Institut für Pharmakologie und Toxikologie, Technischen Universität München, Germany
| | | | | |
Collapse
|
47
|
Feil R, Baldacci PA, Tarttelin E, Rhodes M, Singh PB, Reik W. Cbx-rs2 (M31), a mouse homolog of the Drosophila Heterochromatin protein 1 gene, maps to distal chromosome 11 and is nonallelic to Om. Mamm Genome 1995; 6:469-71. [PMID: 7579889 DOI: 10.1007/bf00360656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- R Feil
- Developmental Genetics and Imprinting Laboratory, Babraham Institute, Cambridge, UK
| | | | | | | | | | | |
Collapse
|
48
|
Feil R, Handel MA, Allen ND, Reik W. Chromatin structure and imprinting: developmental control of DNase-I sensitivity in the mouse insulin-like growth factor 2 gene. Dev Genet 1995; 17:240-52. [PMID: 8565330 DOI: 10.1002/dvg.1020170309] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The insulin-like growth factor 2 (Igf2) gene on distal mouse chromosome 7 is expressed predominantly from the paternal allele. In previous studies we identified two regions of paternal allele-specific methylation; one at approximately 3 kb upstream of promoter 1, and a second in the 3', coding portion of the gene. The 3' region is methylated in an expressing tissue (fetal liver), whereas in a non-expressing tissue (fetal brain), it is not methylated. By contrast, in the 5' region, the paternal allele is highly methylated in all tissues. Here, we have studied another characteristic of chromatin, namely, sensitivity to DNase-I and have focused our developmental analysis on the two differentially methylated regions of Igf2. In the upstream region, four clustered DNase-I hypersensitive sites (HSS) were detected in embryonic stem (ES) cells and in midgestation embryos, but not in neonatal liver or brain. In promoter 1 (P1), at approximately 0.3 kb upstream of exon 1, we detected a tissue-specific HSS that was present in neonatal liver, in which P1 is active, but was absent in ES cells, the embryo, and in neonatal brain. No DNase-I HSS were detected in the 3' differentially methylated region of Igf2. In all these regions, we did not detect differences in DNase-I sensitivity between the parental chromosomes. These results establish major developmental and tissue-specific control of chromatin in the Igf2 locus. The presence of the HSS upstream of Igf2 precedes transcriptional activation of the Igf2 gene and may be indicative of a promoter for another transcript that is transcribed in the opposite direction. The HSS in P1 is largely liver-specific; this promoter therefore is differently regulated than the more general fetal promoters P2 and P3. Whereas methylation can be allele-specific, presumably reflecting the gene imprint, the nuclease sensitivity, as detected by our assay, is not. These results, taken together with previous observations, reveal developmental and tissue-specific complexity in the expression of the parental imprint at the level of chromatin and transcription. We propose that epigenetic features of tissue-specific control and of the control of allelic expression are intricately linked.
Collapse
Affiliation(s)
- R Feil
- Laboratory of Developmental Genetics and Imprinting, Babraham Institute, Cambridge, United Kingdom
| | | | | | | |
Collapse
|
49
|
Abstract
The Insulin-like growth factor 2 (Igf2) and H19 genes are reciprocally imprinted and closely linked. Igf2 encodes a fetal growth-factor and is predominantly expressed from the paternal allele, while H19 is expressed from the maternal allele and encodes a transcript which may downregulate cellular proliferation. One of the epigenetic modifications thought to be involved in parental imprinting is DNA methylation. Here we analyse methylation in two regions of the Igf2 gene, one approx. 3 kb upstream of the gene and one in the 3′ part of the gene. Both regions are more methylated on the expressed paternal chromosome. Genomic sequencing of individual chromosomes in the first region shows this parent-specific methylation to be highly mosaic; interestingly, individual sperm chromosomes carry different methylation patterns into the egg. In the more 3′ region, which is fully methylated in sperm, the level of methylation on the paternal allele is highly tissue-specific and is correlated with expression of the gene in fetal tissues. Hence, the paternal allele is highly methylated in fetal liver (high expression) but is undermethylated in fetal brain (virtually no expression). Adult choroid plexus, a brain tissue in which Igf2 is expressed from both alleles and H19 is not expressed, represents an apparent loss of imprinting. Here, both Igf2 and H19 adopt a paternal type methylation pattern on both parental chromosomes. Analysis of early-passage androgenetic and parthenogenetic embryonic stem (ES) cells shows that the methylation patterns of Igf2 and H19 on maternal and paternal chromosomes are very similar. Androgenetic and parthenogenetic teratomas derived from these ES cells show the appropriate paternal and maternal patterns, respectively, of allelic methylation in both genes. Our results suggest that allelic methylation patterns in Igf2 and H19 arise early in embryogenesis and change progressively during development. Some of these developmental changes are apparently under tissue-specific control.
Collapse
Affiliation(s)
- R Feil
- Laboratory of Developmental Genetics and Imprinting, Babraham Institute, Cambridge, UK
| | | | | | | |
Collapse
|
50
|
Feil R, Charlton J, Bird AP, Walter J, Reik W. Methylation analysis on individual chromosomes: improved protocol for bisulphite genomic sequencing. Nucleic Acids Res 1994; 22:695-6. [PMID: 8127720 PMCID: PMC307863 DOI: 10.1093/nar/22.4.695] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [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: 01/28/2023] Open
Affiliation(s)
- R Feil
- Laboratory of Developmental Genetics and Imprinting, AFRC Babraham Institute, Cambridge, UK
| | | | | | | | | |
Collapse
|