title: Intron Lariat RNA Inhibits MicroRNA Biogenesis by Sequestering the Dicing Complex in Arabidopsis.
abstract: Lariat RNAs formed as by-products of splicing are quickly degraded by the RNA debranching enzyme 1 (DBR1), leading to their turnover. Null dbr1 mutants in both animals and plants are embryo lethal, but the mechanism underlying the lethality remains unclear. Here we characterized a weak mutant allele of DBR1 in Arabidopsis, dbr1-2, and showed that a global increase in lariat RNAs was unexpectedly accompanied by a genome-wide reduction in miRNA accumulation. The dbr1-2 mutation had no effects on expression of miRNA biogenesis genes or primary miRNAs (pri-miRNAs), but the association of pri-miRNAs with the DCL1/HYL1 dicing complex was impaired. Lariat RNAs were associated with the DCL1/HYL1 dicing complex in vivo and competitively inhibited the binding of HYL1 with pri-miRNA. Consistent with the impacts of lariat RNAs on miRNA biogenesis, over-expression of lariat RNAs reduced miRNA accumulation. Lariat RNAs localized in nuclear bodies, and partially co-localize with HYL1, and both DCL1 and HYL1 were mis-localized in dbr1-2. Together with our findings that nearly four hundred lariat RNAs exist in wild type plants and that these lariat RNAs also associate with the DCL1/HYL1 dicing complex in vivo, we thus propose that lariat RNAs, as decoys, inhibit miRNA processing, suggesting a hitherto unknown layer of regulation in miRNA biogenesis.
authors.affiliation: State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.
authors.forename: Ziwei
authors.initials: Z
authors.lastname: Li
authors.affiliation: Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China.
authors.forename: Shengpeng
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.
authors.forename: Jinping
authors.initials: J
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.
authors.forename: Chuanbin
authors.initials: C
authors.lastname: Su
authors.affiliation: State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.
authors.forename: Songxiao
authors.initials: S
authors.lastname: Zhong
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Yuda
authors.initials: Y
authors.lastname: Fang
authors.affiliation: State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Lv
authors.affiliation: Yunnan Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.
authors.forename: Binglian
authors.identifier: http://orcid.org/0000-0001-5650-5348
authors.initials: B
authors.lastname: Zheng
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D007438:Introns / Q000235:genetics; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D050505:Mutant Proteins / Q000235:genetics; D012316:RNA Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics; D012326:RNA Splicing / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D043244:Ribonuclease III / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C420966:HYL1 protein, Arabidopsis; D035683:MicroRNAs; D050505:Mutant Proteins; D016601:RNA-Binding Proteins; C000618222:DBR1 protein, Arabidopsis; D012316:RNA Nucleotidyltransferases; C402383:DCL1 protein, Arabidopsis; D043244:Ribonuclease III