受逆境诱导的水稻Rim2/Hipa假基因转录本选择性加尾和剪接(英文)  

Stress-induced Rim2/Hipa Pseudogene of Rice Exhibits Alternative Tailing and Splicing During Transcription

作　　者：石夏荣[1] 李群[1] 何祖华[1] 

机构地区：[1]中国科学院上海生命科学研究院植物生理生态研究所植物分子遗传国家重点实验室

出　　处：《植物生理与分子生物学学报》2005年第6期607-614,共8页Journal Of Plant Physiology and Molecular Biology

基　　金：国家自然科学基金项目(Nos. 90208010, 30125030);中国科学院创新项目(No. KSCX2-SW-301-02)资助。~~

摘　　要：我们以往的研究证明水稻受病原菌诱导的Rim2/Hipa 因子是水稻基因组所特有的 DNA 转座子超级家族。本实验通过对病原菌诱导的 cDNA文库的筛选和对 EST 数据库的搜索,发现在众多的 Rim2 拷贝中,只有 Rim2-42 因子被表达,其为一个TNP2类转座酶的假基因,其编码区为终止子所打断。序列分析结果表明Rim2转录本被选择性剪接和加尾,而且在两个水稻亚种中的剪接方式有差异,共形成 7 种不同转录本结构,包括一个未知功能的Rim2-XET嵌合转录本,该嵌合转录本为转录通读(read-through)所形成,而 XET 基因是可以被逆境所诱导的。这些结果说明Rim2因子家族可能已失去转座的活性。结果也初步表明Rim2-42 因子插入到了一个 XET 基因启动子的下游,该启动子带动了 Rim2 因子的诱导表达。The rice Rim2/Hipa is a unique stress-induced transposon superfamily recently identified in Oryza genomes. In the present study, we conducted genome-wide screening of full-length Rim2 cDNA from the pathogen-induced cDNA libraries and mining of cDNA databases. Four indica and two japonica types of transcripts were identified, which were transcribed from the same Rim2 pseudogene Rim2-42 that contains premature stop codons in the TNP2-TPase coding region. These data demonstrated that the processing of the Rim2 transcripts exhibited variations within and between the two subspecies. These transcripts were found to be produced by alternative transcription （tailing） or splicing from Rim2-42 under stress conditions. An additional Rim2-like transcript （Rim2-XET）, a chimera of Rim2 and XET genes, were also found to be derived from read-through. These results show that the Rim2 transposon probably loses its transposition capacity during evolution, and that Rim2-42 inserts downstream of the stress-inducible XET promoter, resulting in Rim2 transcript accumulation upon pathogen attack.

关 键 词：水稻 Rim2/Hipa 假基因 转录本 加工 

分 类 号：S511[农业科学—作物学]