title: A nicked group II intron and trans-splicing in liverwort, Marchantia polymorpha, chloroplasts.
abstract: The chloroplast gene rps12 for ribosomal protein S12 in a liverwort, Marchantia polymorpha, is split into three exons by two introns, one of which (intron 1) is discontinuous. Exon 1 of rps12 for the N-terminal portion of the S12 protein is far from exons 2 and 3 for the C-terminal portion on the opposite DNA strand. S1-nuclease protection analysis and Northern hybridization with RNA isolated from the liverwort chloroplasts showed that: (i) the exons 1 and 2-3 of the rps12 gene with the neighboring genes were transcribed separately, (ii) the trans-splicing of intron 1 occurred after the processing of two primary transcripts to two pre-mRNAs, and (iii) there was no particular order for the splicing of intron 1 (trans) and intron 2 (cis) in the rps12 gene. We propose a bimolecular interaction model for trans-splicing by assuming that intermolecular base pairings between two pre-mRNAs result in the formation of the structure typical of group II introns except for disruption in the loop III region. This structure could be constructed in intron 1 of tobacco rps12 gene.
authors.affiliation: Research Center for Cell and Tissue Culture, Kyoto University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kohchi
authors.forename: K
authors.initials: K
authors.lastname: Umesono
authors.forename: Y
authors.initials: Y
authors.lastname: Ogura
authors.forename: Y
authors.initials: Y
authors.lastname: Komine
authors.forename: K
authors.initials: K
authors.lastname: Nakahigashi
authors.forename: T
authors.initials: T
authors.lastname: Komano
authors.forename: Y
authors.initials: Y
authors.lastname: Yamada
authors.forename: H
authors.initials: H
authors.lastname: Ozeki
authors.forename: K
authors.initials: K
authors.lastname: Ohyama
mesh_terms: D001483:Base Sequence; D015152:Blotting, Northern; D002736:Chloroplasts / Q000378:metabolism*; D005796:Genes; D007438:Introns; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D010944:Plants / Q000235:genetics*; D012322:RNA Precursors / Q000235:genetics*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics; D012269:Ribosomal Proteins / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D012322:RNA Precursors; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C034212:ribosomal protein S12