title: Genetic Inactivation of ATRX Leads to a Decrease in the Amount of Telomeric Cohesin and Level of Telomere Transcription in Human Glioma Cells.
abstract: Mutations in ATRX (alpha thalassemia/mental retardation syndrome X-linked), a chromatin-remodeling protein, are associated with the telomerase-independent ALT (alternative lengthening of telomeres) pathway of telomere maintenance in several types of cancer, including human gliomas. In telomerase-positive glioma cells, we found by immunofluorescence that ATRX localized not far from the chromosome ends but not exactly at the telomere termini. Chromatin immunoprecipitation (ChIP) experiments confirmed a subtelomeric localization for ATRX, yet short hairpin RNA (shRNA)-mediated genetic inactivation of ATRX failed to trigger the ALT pathway. Cohesin has been recently shown to be part of telomeric chromatin. Here, using ChIP, we showed that genetic inactivation of ATRX provoked diminution in the amount of cohesin in subtelomeric regions of telomerase-positive glioma cells. Inactivation of ATRX also led to diminution in the amount of TERRAs, noncoding RNAs resulting from transcription of telomeric DNA, as well as to a decrease in RNA polymerase II (RNAP II) levels at the telomeres. Our data suggest that ATRX might establish functional interactions with cohesin on telomeric chromatin in order to control TERRA levels and that one or the other or both of these events might be relevant to the triggering of the ALT pathway in cancer cells that exhibit genetic inactivation of ATRX.
authors.affiliation: UMR CNRS 7292, Université François-Rabelais de Tours, Tours, France.
authors.forename: Rita
authors.initials: R
authors.lastname: Eid
authors.affiliation: UMR CNRS 7292, Université François-Rabelais de Tours, Tours, France.
authors.forename: Marie-Véronique
authors.initials: MV
authors.lastname: Demattei
authors.affiliation: Genetic and Epigenetic Alterations of Genomes, de Duve Institute, Catholic University of Louvain, Brussels, Belgium.
authors.forename: Harikleia
authors.initials: H
authors.lastname: Episkopou
authors.affiliation: Equipe Associée 6306, Instabilité Génétique et Cancer, Université François-Rabelais de Tours, Tours, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Augé-Gouillou
authors.affiliation: Genetic and Epigenetic Alterations of Genomes, de Duve Institute, Catholic University of Louvain, Brussels, Belgium.
authors.forename: Anabelle
authors.initials: A
authors.lastname: Decottignies
authors.affiliation: UMR CNRS 7292, Université François-Rabelais de Tours, Tours, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Grandin
authors.affiliation: UMR CNRS 7292, Université François-Rabelais de Tours, Tours, France michel.charbonneau@univ-tours.fr.
authors.forename: Michel
authors.initials: M
authors.lastname: Charbonneau
mesh_terms: D018797:Cell Cycle Proteins / Q000032:analysis / Q000378:metabolism*; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis / Q000378:metabolism*; D004265:DNA Helicases / Q000032:analysis / Q000235:genetics*; D005910:Glioma / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics*; D034622:RNA Interference; D012319:RNA Polymerase II / Q000378:metabolism; D022661:RNA, Untranslated / Q000378:metabolism; D019098:Telomerase / Q000378:metabolism; D016615:Telomere / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D059505:Telomere Homeostasis; D014158:Transcription, Genetic; D000075924:X-linked Nuclear Protein; D000097722:Cohesins
chemical_list: D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004265:DNA Helicases; D009687:Nuclear Proteins; D012319:RNA Polymerase II; D022661:RNA, Untranslated; D019098:Telomerase; D000075924:X-linked Nuclear Protein; D000097722:Cohesins; C092332:ATRX protein, human