title: The Arabidopsis U12-type spliceosomal protein U11/U12-31K is involved in U12 intron splicing via RNA chaperone activity and affects plant development.
abstract: U12 introns are removed from precursor-mRNA by a U12 intron-specific spliceosome that contains U11 and U12 small nuclear ribonucleoproteins. Although several proteins unique to the U12-type spliceosome have been identified, the manner by which they affect U12-dependent intron splicing as well as plant growth and development remain largely unknown. Here, we assessed the role of U11/U12-31K, a U12-type spliceosomal protein in Arabidopsis thaliana. T-DNA-tagged homozygote lines for U11/U12-31K could not be obtained, and heterozygote mutants were defective for seed maturation, indicating that U11/U12-31K is essential for the normal development of Arabidopsis. Knockdown of U11/U12-31K by artificial microRNA caused a defect in proper U12 intron splicing, resulting in abnormal stem growth and development of Arabidopsis. This defect in proper splicing was not restricted to specific U12-type introns, but most U12 intron splicing was influenced by U11/U12-31K. The stunted inflorescence stem growth was recovered by exogenously applied gibberellic acid (GA), but not by cytokinin, auxin, or brassinosteroid. GA metabolism-related genes were highly downregulated in U11/U12-31K knockdown plants. Importantly, U11/U12-31K was determined to harbor RNA chaperone activity. We propose that U11/U12-31K is an RNA chaperone that is indispensible for proper U12 intron splicing and for normal growth and development of plants.
authors.affiliation: Department of Plant Biotechnology and Agricultural Plant Stress Research Center, College of Agriculture and Life Sciences, Chonam National University, Gwangju 500-757, Korea.
authors.forename: Won Yong
authors.initials: WY
authors.lastname: Kim
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Jung
authors.forename: Kyung Jin
authors.initials: KJ
authors.lastname: Kwak
authors.forename: Min Kyung
authors.initials: MK
authors.lastname: Kim
authors.forename: Seung Han
authors.initials: SH
authors.lastname: Oh
authors.forename: Yeon Soo
authors.initials: YS
authors.lastname: Han
authors.forename: Hunseung
authors.initials: H
authors.lastname: Kang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000502:physiology*; D055785:Gene Knockdown Techniques; D007438:Introns; D012326:RNA Splicing; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017381:Spliceosomes
chemical_list: D029681:Arabidopsis Proteins