title: Ordered processing and splicing in a polycistronic transcript in liverwort chloroplasts.
abstract: From the complete sequence of the chloroplast DNA in a liverwort, Marchantia polymorpha, an unidentified open reading frame, ORF203, was found between the psbB and rps12' (trans-split) genes. ORF203 was a split gene consisting of three exons and two group II introns. Multiple transcripts for ORF203 were detected on Northern blots of the chloroplast RNA preparation. The ORF203 locus was primarily co-transcribed with the downstream genes rps12' and rpl20, and then processed into a monomeric precursor. S1 nuclease mapping gave the transcription initiation site 52 nucleotides upstream from the coding sequence of ORF203. The spliced RNA molecules were identified, as predicted, by the use of synthetic oligodeoxyribonucleotide probes specific to ligated exon sequences. The splicing reaction proceeded successively from the 5' to 3' direction. These results indicate that ordered RNA processing occurs in the chloroplast of land plants. Trans-membrane analysis by a computer indicated that ORF203 gene product could be associated with a chloroplast membrane.
authors.affiliation: Research Center for Cell and Tissue Culture, Faculty of Agriculture, Kyoto University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kohchi
authors.forename: Y
authors.initials: Y
authors.lastname: Ogura
authors.forename: K
authors.initials: K
authors.lastname: Umesono
authors.forename: Y
authors.initials: Y
authors.lastname: Yamada
authors.forename: T
authors.initials: T
authors.lastname: Komano
authors.forename: H
authors.initials: H
authors.lastname: Ozeki
authors.forename: K
authors.initials: K
authors.lastname: Ohyama
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D002736:Chloroplasts; D004247:DNA / Q000235:genetics; D015252:Deoxyribonucleases, Type II Site-Specific; D004720:Endonucleases; D005091:Exons; D007438:Introns; D008969:Molecular Sequence Data; D005810:Multigene Family; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D010944:Plants; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D015347:RNA Probes; D012323:RNA Processing, Post-Transcriptional; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000235:genetics; D015719:Single-Strand Specific DNA and RNA Endonucleases; D014158:Transcription, Genetic
chemical_list: D012322:RNA Precursors; D015347:RNA Probes; D012333:RNA, Messenger; D012269:Ribosomal Proteins; D004247:DNA; D004720:Endonucleases; C024388:CTGCAG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific; D015719:Single-Strand Specific DNA and RNA Endonucleases