title: Alternative mRNA processing increases the complexity of microRNA-based gene regulation in Arabidopsis.
abstract: MicroRNAs (miRNAs) represent an important class of sequence-specific, trans-acting endogenous small RNA molecules that modulate gene expression at the post-transcriptional level. They function by binding to partial complementary cis-regulatory sites (miRNA binding sites) in their target mRNAs. Based on two recent observations from plant genome studies, namely that alternative splicing is a common phenomenon and that miRNA regulates a significant proportion of the transcriptome, we hypothesize that there may be a mechanism for gene regulation that involves both processes. In the present study, we performed a systemic search in the model plant Arabidopsis thaliana using annotated gene models as well as publically available high-throughput RNA sequencing data with a total of 570 million reads. Of the 354 high-confidence miRNA binding sites identified in Arabidopsis, at least 44 (12.4%) were affected by alternative splicing such that mRNA isoforms of the same miRNA target gene differ in the sequences encoding the miRNA binding sites. By simulation, we found that the frequency of alternative splicing at miRNA binding sites is significantly higher than at other regions. Comparative and functional analyses further indicated that the alternative splicing events are important for target gene expression and miRNA action. Together our results show that alternative splicing of miRNA binding sites is a plausible mechanism for attenuating miRNA-mediated gene regulation.
authors.affiliation: Department of Biology, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: Xiaozeng
authors.initials: X
authors.lastname: Yang
authors.forename: Huiyong
authors.initials: H
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Li
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D003198:Computer Simulation; D017124:Conserved Sequence / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D018745:Genome, Plant / Q000235:genetics; D059014:High-Throughput Nucleotide Sequencing; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D030821:Plants, Genetically Modified; D059368:RNA Isoforms / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D017423:Sequence Analysis, RNA; D014157:Transcription Factors / Q000235:genetics; D059467:Transcriptome / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D035683:MicroRNAs; C559759:Mirn156 microRNA, Arabidopsis; D059368:RNA Isoforms; D012333:RNA, Messenger; D018749:RNA, Plant; C483287:SPL4 protein, Arabidopsis; D014157:Transcription Factors