2006 Fiscal Year Final Research Report Summary
Diversity and control of RNA export
| Project/Area Number |
14035225
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Biological Sciences
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| Research Institution | Kyoto University |
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Principal Investigator |
OHNO Mutsuhito Kyoto University, The Institute for Virus Research Department of Genetics and Molecular Biology, Laboratory of Biochemistry, Professor (80201979)
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| Project Period (FY) |
2002 – 2006
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| Keywords | gene / nucleic acid / gene expression control / protein |
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| Research Abstract |
Different RNA species, such as tRNAs, U snRNAs, mRNAs and rRNAs, utilize distinct export pathways, i. e., distinct sets of export factors. Accumulating evidence shows that the pathway of RNA export can influence the fate of a given RNA in the cytoplasm, indicating the biological importance of the choice of RNA export pathway. This means that the cellular export machinery must be able to discriminate distinct RNA species, and therefore each RNA species should have identifying features that specify its export pathway ("ID elements"). We are mainly focusing on mRNAs and performing a systematic search for identity elements used in export of mRNAs. During the period, we could identify three ID elements, namely "intron", "RNA length" and "poly(A) tail". These results greatly contribute to the understanding of RNA export and gene expression.
Intron-containing pre-mRNAs are normally retained in the nucleus until they are spliced to produce mature mRNAs that are exported to the cytoplasm. The nuclear retention of pre-mRNAs is essential for proper gene expression. It secures pre-mRNAs to be efficiently spliced since splicing mainly occurs in the nucleus. It also secures pre-mRNAs not to be translated since translation of pre-mRNAs would possibly produce toxic abnormal proteins for the cell. However, the nuclear retention mechanisms of pre-mRNAs are not well understood. We found that exonic sequences termed purine-rich exonic splicing enhancers (ESEs) are involved in that process. These results give an important clue to the understanding of this enigmatic process.
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