1988 Fiscal Year Final Research Report Summary
Analysis of expression mechanisms for trans-split gene in a liverwort, Marchantia polymorpha chloroplasts.
| Project/Area Number |
62480056
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
応用生物化学・栄養化学
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| Research Institution | Kyoto University |
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Principal Investigator |
OHYAMA Kanji Associate Professor, Faculty of Agriculture, Kyoto University, 農学部, 助教授 (40135546)
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| Project Period (FY) |
1987 – 1988
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| Keywords | chloroplast genome / liverwort / trans-splicing / ribosomal protein / exon / intron |
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| Research Abstract |
A number of chloroplast genes are interrupted by introns and thus require post-transcriptional RNA splicing for the gene expression. Chloroplast introns belong to either group I or group II depending on their secondary structures, which was first elucidated in mitochondoria. This report deals with trans-splicing of chlorolast ribosomal protein S12 gene. The chloroplast gene RPS12 for ribosomal protein S12 in a liverwort, M. polymorpha, is aplit 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 stand. S1-nuclease protection analysis and northern hybridization with RNA isolated from the licerwort 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 per- mRNAs, (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-mRNA 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.
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