title: THO2, a core member of the THO/TREX complex, is required for microRNA production in Arabidopsis.
abstract: The THO/TREX complex mediates transport of nascent mRNAs from the nucleus towards the cytoplasm in animals, and has a role in small interfering RNA-dependent processes in plants. Here we describe five mutant alleles of Arabidopsis thaliana THO2, which encodes a core subunit of the plant THO/TREX complex. tho2 mutants present strong developmental defects resembling those in plants compromised in microRNA (miRNA) activity. In agreement, not only were the levels of siRNAs reduced in tho2 mutants, but also those of mature miRNAs. As a consequence, a feedback mechanism is triggered, increasing the amount of miRNA precursors, and finally causing accumulation of miRNA-targeted mRNAs. Yeast two-hybrid experiments and confocal microscopy showed that THO2 does not appear to interact with any of the known miRNA biogenesis components, but rather with the splicing machinery, implying an indirect role of THO2 in small RNA biogenesis. Using an RNA immunoprecipitation approach, we found that THO2 interacts with miRNA precursors, and that tho2 mutants fail to recruit such precursors into the miRNA-processing complex, explaining the reduction in miRNA production in this mutant background. We also detected alterations in the splicing pattern of genes encoding serine/arginine-rich proteins in tho2 mutants, supporting a previously unappreciated role of the THO/TREX complex in alternative splicing.
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Korea.
authors.forename: Anchilie G
authors.initials: AG
authors.lastname: Francisco-Mangilet
authors.affiliation: Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076, Tübingen, Germany.
authors.forename: Patricia
authors.initials: P
authors.lastname: Karlsson
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Korea.
authors.forename: Myung-Hee
authors.initials: MH
authors.lastname: Kim
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Korea.
authors.forename: Hyeon Ju
authors.initials: HJ
authors.lastname: Eo
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Korea.
authors.forename: Sung Aeong
authors.initials: SA
authors.lastname: Oh
authors.affiliation: Department of Biology, Kyungpook National University, Daegu, 702-701, Korea.
authors.forename: Jeong Hoe
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076, Tübingen, Germany.
authors.forename: Franceli Rodrigues
authors.initials: FR
authors.lastname: Kulcheski
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Korea.|National Academy of Agricultural Science, Rural Development Administration, Jeonju, 560-500, Korea.
authors.forename: Soon Ki
authors.initials: SK
authors.lastname: Park
authors.affiliation: Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral/CONICET, 3000, Santa Fe, Argentina.
authors.forename: Pablo Andrés
authors.initials: PA
authors.lastname: Manavella
mesh_terms: D017398:Alternative Splicing; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D030821:Plants, Genetically Modified; D034741:RNA, Small Interfering / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C420966:HYL1 protein, Arabidopsis; D035683:MicroRNAs; D046912:Multiprotein Complexes; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; C000595082:SR34b protein, Arabidopsis; C000610749:THO2 protein, Arabidopsis
keywords: Arabidopsis thaliana; THO/TREX complex; THO2; gene silencing; micro RNA; small RNAs