title: A Ribonucleoprotein Supercomplex Involved in trans-Splicing of Organelle Group II Introns.
abstract: In the chloroplast of the green alga Chlamydomonas reinhardtii, two discontinuous group II introns, psaA-i1 and psaA-i2, splice in trans, and thus their excision process resembles the nuclear spliceosomal splicing pathway. Here, we address the question whether fragmentation of trans-acting RNAs is accompanied by the formation of a chloroplast spliceosome-like machinery. Using a combination of liquid chromatography-mass spectrometry (LC-MS), size exclusion chromatography, and quantitative RT-PCR, we provide the first characterization of a high molecular weight ribonucleoprotein apparatus participating in psaA mRNA splicing. This supercomplex contains two subcomplexes (I and II) that are responsible for trans-splicing of either psaA-i1 or psaA-i2. We further demonstrate that both subcomplexes are associated with intron RNA, which is a prerequisite for the correct assembly of subcomplex I. This study contributes further to our view of how the eukaryotic nuclear spliceosome evolved after bacterial endosymbiosis through fragmentation of self-splicing group II introns into a dynamic, protein-rich RNP machinery.
authors.affiliation: From the Lehrstuhl für Allgemeine und Molekulare Botanik.
authors.forename: Olga
authors.initials: O
authors.lastname: Reifschneider
authors.affiliation: From the Lehrstuhl für Allgemeine und Molekulare Botanik.
authors.forename: Christina
authors.initials: C
authors.lastname: Marx
authors.affiliation: From the Lehrstuhl für Allgemeine und Molekulare Botanik.
authors.forename: Jessica
authors.initials: J
authors.lastname: Jacobs
authors.affiliation: the Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Otto-Hahn-Strasse 6b, 44227 Dortmund, Germany, and.
authors.forename: Laxmikanth
authors.initials: L
authors.lastname: Kollipara
authors.affiliation: the Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Otto-Hahn-Strasse 6b, 44227 Dortmund, Germany, and.|the School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Meston Walk, Old Aberdeen AB24 3UE, United Kingdom.|the Medizinische Fakultät, Medizinisches Proteom-Center (MPC), and.
authors.forename: Albert
authors.initials: A
authors.lastname: Sickmann
authors.affiliation: the Department of Analytical Chemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Wolters
authors.affiliation: From the Lehrstuhl für Allgemeine und Molekulare Botanik, ulrich.kueck@rub.de.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kück
mesh_terms: D016825:Chlamydomonas reinhardtii / Q000235:genetics* / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism*; D007438:Introns; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D017381:Spliceosomes / Q000235:genetics / Q000378:metabolism; D020040:Trans-Splicing
chemical_list: D012261:Ribonucleoproteins
keywords: Chlamydomonas reinhardtii; RNA processing; RNA splicing; chloroplast; evolution; gene regulation; group II intron; ribonucleoprotein complex; spliceosome; trans-splicing