title: Polypyrimidine tract binding protein homologs from Arabidopsis are key regulators of alternative splicing with implications in fundamental developmental processes.
abstract: Alternative splicing (AS) generates transcript variants by variable exon/intron definition and massively expands transcriptome diversity. Changes in AS patterns have been found to be linked to manifold biological processes, yet fundamental aspects, such as the regulation of AS and its functional implications, largely remain to be addressed. In this work, widespread AS regulation by Arabidopsis thaliana Polypyrimidine tract binding protein homologs (PTBs) was revealed. In total, 452 AS events derived from 307 distinct genes were found to be responsive to the levels of the splicing factors PTB1 and PTB2, which predominantly triggered splicing of regulated introns, inclusion of cassette exons, and usage of upstream 5' splice sites. By contrast, no major AS regulatory function of the distantly related PTB3 was found. Dependent on their position within the mRNA, PTB-regulated events can both modify the untranslated regions and give rise to alternative protein products. We find that PTB-mediated AS events are connected to diverse biological processes, and the functional implications of selected instances were further elucidated. Specifically, PTB misexpression changes AS of PHYTOCHROME INTERACTING FACTOR6, coinciding with altered rates of abscisic acid-dependent seed germination. Furthermore, AS patterns as well as the expression of key flowering regulators were massively changed in a PTB1/2 level-dependent manner.
authors.affiliation: Center for Plant Molecular Biology, University of Tübingen, 72076 Tuebingen, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Rühl
authors.forename: Eva
authors.initials: E
authors.lastname: Stauffer
authors.forename: André
authors.initials: A
authors.lastname: Kahles
authors.forename: Gabriele
authors.initials: G
authors.lastname: Wagner
authors.forename: Gabriele
authors.initials: G
authors.lastname: Drechsel
authors.forename: Gunnar
authors.initials: G
authors.lastname: Rätsch
authors.forename: Andreas
authors.initials: A
authors.lastname: Wachter
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D017398:Alternative Splicing; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000378:metabolism; D016000:Cluster Analysis; D005091:Exons; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D018525:Germination; D007438:Introns; D010937:Plant Growth Regulators / Q000378:metabolism; D030821:Plants, Genetically Modified; D038941:Polypyrimidine Tract-Binding Protein / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D011994:Recombinant Proteins; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D013997:Time Factors
chemical_list: D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D010937:Plant Growth Regulators; D038941:Polypyrimidine Tract-Binding Protein; D012333:RNA, Messenger; D018749:RNA, Plant; D011994:Recombinant Proteins; C497730:PIF6 protein, Arabidopsis