Construction of gene rearrangement system by RMu transposon in rice

点击翻译按钮获取中文摘要

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.