| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
An Indica cultivar of rice carries a 4374 bp element flanked by a 9 bp genomic repeat. The ends of this element comprise 193 bp terminal inverted repeats (TIRs) that are identical in their most terminal 90 bps and 87% identical throughout. Between the TIRs, there is an open reading frame that translates to a protein that is homologous to the transposase MURA encoded in the autonomous maize Mu element MuDR.On the basis of overall structure, the characteristic 9 bp genomic repeat and MURA homology, we conclude that the rice element, RMul is a close and obvious relative of the autonomous maize transposon MuDR, and is more related to maize elements than to any Mu-type element previously reported in rice. Copy number of RMu elements is moderate in all cultivars examined. Transcript of the orf of RMul-IR36 was detected in some Japonica strains. Two kinds of splicing products were transcribed, and both specify in-frame product. Indica lines did not transcribe RMu. However, cold stress given in intervals activated transcription of the rmuA gene in RMu-IR36, and the primary transcript was correctly processed. The specificity of induction conditions was surprising. Database searches found that RMu in rice is a member of the same branch of Angiosperm Mu elements as is the autonomous element MuDR in maize, except RMul does not contain a mudrB ortholog. This is the first such element to be found.
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