title: Intermolecular recognition of the non-coding RNA 7SK and HEXIM protein in perspective.
abstract: A 7SKsnRNP complex, comprising the non-coding RNA 7SK and proteins MePCE and LARP7, participates in the regulation of the transcription elongation by RNA-polymerase II in higher eukaryotes. Binding of a HEXIM protein triggers the inhibition of the kinase complex P-TEFb, a key actor of the switch from paused transcription to elongation. The present paper reviews what is known about the specific recognition of the 7SK RNA by the HEXIM protein. HEXIM uses an arginine-rich motif (ARM) peptide to bind one specific site in the 5'-hairpin of the 7SK RNA. Since HEXIM forms a dimer, what happens with the second ARM impacts the assembly symmetry. In order to help sort through possible models, a combination of native mass spectrometry and electrophoretic mobility shift assays was used. It provides evidence that only one ARM of the HEXIM dimer is directly binding to the RNA hairpin and that another sequence downstream of the ARM participates in a second binding event allowing the other monomer of HEXIM to bind the RNA.
authors: Department of Integrated Structural Biology, Centre for Integrative Biology (CBI), Institute of Genetics and of Molecular and Cellular Biology (IGBMC) 67404 Illkirch, France; Centre National de la Recherche Scientifique (CNRS) UMR 7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale (INSERM) U964, Illkirch, France; Université de Strasbourg, Strasbourg, France; Biotechnologie et Signalisation Cellulaire UMR 7242, Ecole Supérieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, BP 10413, F-67412 Illkirch, France. Electronic address: d.martinez@unistra.fr.
authors: Denise
authors: D
authors: Martinez-Zapien
authors: BioOrganic Mass Spectrometry Laboratory (LSMBO), Université de Strasbourg, IPHC, 25 rue Becquerel, 67087 Strasbourg, France; CNRS, UMR7178, 67087 Strasbourg, France; Center for Infection and Immunity of Lille (CIIL), Institut Pasteur de Lille, CNRS UMR 8204, INSERM U1019, Université Lille Nord de France, 1 rue du Pr. Calmette, 59000 Lille, France. Electronic address: Jean-Michel.Saliou@pasteur-lille.fr.
authors: Jean-Michel
authors: JM
authors: Saliou
authors: Department of Functional Genomics, Institut de Biologie de l''Ecole Normale Supérieure (IBENS), 75005 Paris, France; CNRS UMR 8197, 75005 Paris, France; INSERM U1024, 75005 Paris, France; Key Laboratory of Brain Functional Genomics, East China Normal University (ECNU), Shanghai, PR China. Electronic address: roxane0313@gmail.com.
authors: Xiao
authors: X
authors: Han
authors: BioOrganic Mass Spectrometry Laboratory (LSMBO), Université de Strasbourg, IPHC, 25 rue Becquerel, 67087 Strasbourg, France; CNRS, UMR7178, 67087 Strasbourg, France. Electronic address: cedric.armanene@unistra.fr.
authors: Cedric
authors: C
authors: Atmanene
authors: Department of Functional Genomics, Institut de Biologie de l''Ecole Normale Supérieure (IBENS), 75005 Paris, France; CNRS UMR 8197, 75005 Paris, France; INSERM U1024, 75005 Paris, France. Electronic address: proux@biologie.ens.fr.
authors: Florence
authors: F
authors: Proux
authors: BioOrganic Mass Spectrometry Laboratory (LSMBO), Université de Strasbourg, IPHC, 25 rue Becquerel, 67087 Strasbourg, France; CNRS, UMR7178, 67087 Strasbourg, France. Electronic address: sarah.cianferani@unistra.fr.
authors: Sarah
authors: S
authors: Cianférani
authors: Department of Functional Genomics, Institut de Biologie de l''Ecole Normale Supérieure (IBENS), 75005 Paris, France; CNRS UMR 8197, 75005 Paris, France; INSERM U1024, 75005 Paris, France. Electronic address: dock@biologie.ens.fr.
authors: Anne-Catherine
authors: AC
authors: Dock-Bregeon
mesh_terms: D001665:Binding Sites / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D013058:Mass Spectrometry; D008780:Methyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D022661:RNA, Untranslated / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors
chemical_list: C476123:HEXIM1 protein, human; C528908:Larp7 protein, human; D022661:RNA, Untranslated; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D014157:Transcription Factors; C547279:MePCE protein, human; D008780:Methyltransferases
keywords: HEXIM; Molecular interaction; Native mass spectrometry; Transcription regulation; non-coding RNA 7SK