title: The Arabidopsis THO/TREX component TEX1 functionally interacts with MOS11 and modulates mRNA export and alternative splicing events.
abstract: We identify proteins that associate with the THO core complex, and show that the TEX1 and MOS11 components functionally interact, affecting mRNA export and splicing as well as plant development. TREX (TRanscription-EXport) is a multiprotein complex that plays a central role in the coordination of synthesis, processing and nuclear export of mRNAs. Using targeted proteomics, we identified proteins that associate with the THO core complex of Arabidopsis TREX. In addition to the RNA helicase UAP56 and the mRNA export factors ALY2-4 and MOS11 we detected interactions with the mRNA export complex TREX-2 and multiple spliceosomal components. Plants defective in the THO component TEX1 or in the mRNA export factor MOS11 (orthologue of human CIP29) are mildly affected. However, tex1 mos11 double-mutant plants show marked defects in vegetative and reproductive development. In tex1 plants, the levels of tasiRNAs are reduced, while miR173 levels are decreased in mos11 mutants. In nuclei of mos11 cells increased mRNA accumulation was observed, while no mRNA export defect was detected with tex1 cells. Nevertheless, in tex1 mos11 double-mutants, the mRNA export defect was clearly enhanced relative to mos11. The subnuclear distribution of TEX1 substantially overlaps with that of splicing-related SR proteins and in tex1 plants the ratio of certain alternative splicing events is altered. Our results demonstrate that Arabidopsis TEX1 and MOS11 are involved in distinct steps of the biogenesis of mRNAs and small RNAs, and that they interact regarding some aspects, but act independently in others.
authors.affiliation: Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Brian B
authors.initials: BB
authors.lastname: Sørensen
authors.affiliation: Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Hans F
authors.initials: HF
authors.lastname: Ehrnsberger
authors.affiliation: Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Esposito
authors.affiliation: Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Pfab
authors.affiliation: Department for Biochemistry I, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Astrid
authors.initials: A
authors.lastname: Bruckmann
authors.affiliation: Department for Biochemistry I, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Judith
authors.initials: J
authors.lastname: Hauptmann
authors.affiliation: Department for Biochemistry I, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Gunter
authors.initials: G
authors.lastname: Meister
authors.affiliation: Department for Biochemistry II, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Merkl
authors.affiliation: Department for Biochemistry III, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schubert
authors.affiliation: Department for Biochemistry III, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
authors.forename: Gernot
authors.initials: G
authors.lastname: Längst
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstr. 3, 06466, Stadt Seeland, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Melzer
authors.affiliation: Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany. Marion.Grasser@ur.de.
authors.forename: Marion
authors.initials: M
authors.lastname: Grasser
authors.affiliation: Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany. Klaus.Grasser@ur.de.
authors.forename: Klaus D
authors.initials: KD
authors.lastname: Grasser
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D017360:Arabidopsis / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D056626:Inflorescence / Q000378:metabolism / Q000648:ultrastructure; D008954:Models, Biological; D010641:Phenotype; D011485:Protein Binding; D014176:Protein Biosynthesis; D034443:RNA Transport; D012333:RNA, Messenger / Q000378:metabolism; D018749:RNA, Plant / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C556905:MOS11 protein, Arabidopsis; D012333:RNA, Messenger; D018749:RNA, Plant; D016601:RNA-Binding Proteins; C000614449:TEX1 protein, Arabidopsis
keywords: Chromatin; Development; Protein complexes; RNA polymerase II; mRNA processing/export