title: Transcription termination and chimeric RNA formation controlled by Arabidopsis thaliana FPA.
abstract: Alternative cleavage and polyadenylation influence the coding and regulatory potential of mRNAs and where transcription termination occurs. Although widespread, few regulators of this process are known. The Arabidopsis thaliana protein FPA is a rare example of a trans-acting regulator of poly(A) site choice. Analysing fpa mutants therefore provides an opportunity to reveal generic consequences of disrupting this process. We used direct RNA sequencing to quantify shifts in RNA 3' formation in fpa mutants. Here we show that specific chimeric RNAs formed between the exons of otherwise separate genes are a striking consequence of loss of FPA function. We define intergenic read-through transcripts resulting from defective RNA 3' end formation in fpa mutants and detail cryptic splicing and antisense transcription associated with these read-through RNAs. We identify alternative polyadenylation within introns that is sensitive to FPA and show FPA-dependent shifts in IBM1 poly(A) site selection that differ from those recently defined in mutants defective in intragenic heterochromatin and DNA methylation. Finally, we show that defective termination at specific loci in fpa mutants is shared with dicer-like 1 (dcl1) or dcl4 mutants, leading us to develop alternative explanations for some silencing roles of these proteins. We relate our findings to the impact that altered patterns of 3' end formation can have on gene and genome organisation.
authors.affiliation: College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom.
authors.forename: Céline
authors.initials: C
authors.lastname: Duc
authors.forename: Alexander
authors.initials: A
authors.lastname: Sherstnev
authors.forename: Christian
authors.initials: C
authors.lastname: Cole
authors.forename: Geoffrey J
authors.initials: GJ
authors.lastname: Barton
authors.forename: Gordon G
authors.initials: GG
authors.lastname: Simpson
mesh_terms: D017398:Alternative Splicing / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation / Q000235:genetics; D005091:Exons; D020868:Gene Silencing; D006570:Heterochromatin / Q000235:genetics; D056484:Jumonji Domain-Containing Histone Demethylases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D016601:RNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D043244:Ribonuclease III / Q000235:genetics / Q000378:metabolism; D061806:Transcription Termination, Genetic
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C432432:FPA protein, Arabidopsis; D006570:Heterochromatin; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C526313:IBM1 protein, Arabidopsis; D056484:Jumonji Domain-Containing Histone Demethylases; C402383:DCL1 protein, Arabidopsis; D043244:Ribonuclease III