植物一个新box H/ACA snoRNA的鉴定及功能分析

Identification and functional analysis of a novel box H/ACA snoRNA from plant by computational strategy

通过生物信息学方法对拟南芥基因组序列进行搜索,发现两个新的非编码小分子RNA基因,分别命名为AthsnoR206 a和AthsnoR206b。它们相距约170nt,位于蛋白质基因间隔区。MFOLD二级结构预测这两个RNA均具有典型的box H/ACAsnoRNA"发夹-铰链-发夹-尾巴"结构,符合box H/ACA snoRNA的判定标准;两个RNA分子的反义序列一致,可以判定它们为同一基因的两个拷贝。分析预测snoR206的两段反义序列分别指导拟南芥rRNA小亚基U1717位点和大亚基U2181位点的假尿嘧啶化修饰。在其它13种包括单子叶植物和双子叶植物在内的植物搜索到14个snoR206同源分子,其中12个发现于表达序列标签中,表明该snoRNA在植物中表达且广泛存在。具有双功能的snoR206在人和酵母中的部分功能同源分子分别为U70和snR32,表明其祖先分子在进化过程中存在分子重组。

Two novel small non-coding RNAs were identified after screening genome sequences of Arabidopsis thaliana by using computational strategies,which were named AthsnoR206a and AthsnoR206b respectively.They were just about 170 nt apart and located intergenic regions between two protein-coding genes.They possess ＂helix-hinge-helix-tail＂ secondary structure revealed by mfold program,which was characteristic of box H/ACA snoRNAs;both novel snoRNAs possess the same antisense elements,which were essence to confirming that they were two copies of the same gene.Bioinformatics analysis revealed that snoR206 was supposed to direct pseudouridylations in 18S rRNA at U1717 and 25S rRNA at U2181.14 more snoR206 homologies were identified in other plants including both Eudicots and Monocots.Most of snoR206 homologies were identified in EST database,revealing snoR206s do transcribe and are common in plants.SnoR206 is a difunctional snoRNA,whose partial functional homologues are U70 in human and snR32 in yeast respectively.The existence of U70 and snR32 revealed recombinations occurred during the evolution of snoR206 ancestor.