水稻25S核糖体RNA2′-O-核糖甲基化位点的测定  

Detection of 2′-O-ribose Methylation Sites on Rice 25 S rRNA

作　　者：李伟[1] 江舸[1] 金由辛[1] 王德宝 

机构地区：[1]中国科学院上海生命科学研究院生物化学与细胞生物学研究所分子生物学国家重点实验室,上海200031

出　　处：《生物化学与生物物理学报》2003年第3期289-295,共7页

基　　金：中国科学院"十五"科技创新项目资助 (No .KSCX2 2 0 4)~~

摘　　要：核糖 2′ O 甲基化修饰是真核生物核糖体RNA上的一种极为普遍的修饰方式。为了测定水稻 2 5S核糖体RNA上发生甲基化修饰的具体位点 ,设计并纯化了一系列与水稻 2 5S和酵母 2 8S核糖体RNA均配对的引物 ,在测定水稻核糖体RNA甲基化位点的同时 ,将酵母核糖体RNA甲基化位点的测定作为对照 ,在同一条件下 ,分别以水稻及酵母总RNA为模板进行dNTP浓度依赖的引物延伸反应。在测得的水稻甲基化位点中 ,有 3 1个位点是与酵母共有的 ,占酵母 2 8S核糖体RNA的甲基化位点总数的 80 %以上。另外 ,通过与已经测定的拟南芥 2 5S核糖体RNA上的甲基化位点进行比较 ,在水稻中又确定了与拟南芥相同的 5 4个甲基化位点。最终在水稻 2 5S核糖体RNA中 ,初步确定了 85个甲基化位点 ,并绘制了水稻 2 5S核糖体RNA的甲基化位点分布图。这些结果表明在不同的真核生物中 ,核糖体RNA上大部分位点核糖的甲基化修饰是保守的 ,而且亲缘关系越近 ,其保守性越强。结果还表明 ,高等植物核糖体RNA上有大量的核糖甲基化修饰位点 ,并且其中相邻的位点均被甲基化修饰的数量明显高于其他生物。所测得的甲基化位点将为进一步寻找植物中新的C/D框小分子核仁RNA(sonRNA)Ribose methylation is a widespread type of nucleotide modification in rRNA. In order to map the methylation sites of rice 25 S rRNA, a series of primers complementary to both yeast 28 S and rice 25 S rRNA simultaneously were synthesized. Primer extensions at different dNTP concentrations were carried out to detect the methylation sites of both yeast and rice rRNAs. The data showed that over 80% of the methylation sites in yeast 28 S rRNA was also detected in rice. In addition, compared with the known methylation sites of Arabidopsis 25 S rRNA, other 54 sites probably methylated in rice were found in Arabidopsis. Thus, there are 85 methylation sites detected altogether; the distribution of the methyl sites in rice 25 S rRNA was determined. The results show that most of the sites are conserved among different species, especially between closely related species. And remarkably, there are much more ribose methylation sites in plant rRNA, and the propinquous methylation sites in plants are more frequent than those in other eukaryotes. Moreover, the data provide the most important clue for searching new box C/D snoRNAs.

关 键 词：水稻 25S核糖体 RNA2′-O-核糖甲基化位点 测定 植物 

分 类 号：Q522[生物学—生物化学]