Marker Claudia, Zemann Anja, Terhörst Tanja, Kiefmann Martin, Kastenmayer James P, Green Pamela, Bachellerie Jean-Pierre, Brosius Jürgen, Hüttenhofer Alexander
Institute of Experimental Pathology, ZMBE, Von-Esmarch-Str 56, 48149 Münster, Germany.
Curr Biol. 2002 Dec 10;12(23):2002-13. doi: 10.1016/s0960-9822(02)01304-0.
Genomes from all organisms known to date express two types of RNA molecules: messenger RNAs (mRNAs), which are translated into proteins, and non-messenger RNAs, which function at the RNA level and do not serve as templates for translation.
We have generated a specialized cDNA library from Arabidopsis thaliana to investigate the population of small non-messenger RNAs (snmRNAs) sized 50-500 nt in a plant. From this library, we identified 140 candidates for novel snmRNAs and investigated their expression, abundance, and developmental regulation. Based on conserved sequence and structure motifs, 104 snmRNA species can be assigned to novel members of known classes of RNAs (designated Class I snmRNAs), namely, small nucleolar RNAs (snoRNAs), 7SL RNA, U snRNAs, as well as a tRNA-like RNA. For the first time, 39 novel members of H/ACA box snoRNAs could be identified in a plant species. Of the remaining 36 snmRNA candidates (designated Class II snmRNAs), no sequence or structure motifs were present that would enable an assignment to a known class of RNAs. These RNAs were classified based on their location on the A. thaliana genome. From these, 29 snmRNA species located to intergenic regions, 3 located to intronic sequences of protein coding genes, and 4 snmRNA candidates were derived from annotated open reading frames. Surprisingly, 15 of the Class II snmRNA candidates were shown to be tissue-specifically expressed, while 12 are encoded by the mitochondrial or chloroplast genome.
Our study has identified 140 novel candidates for small non-messenger RNA species in the plant A. thaliana and thereby sets the stage for their functional analysis.
迄今为止已知的所有生物体的基因组都表达两种类型的RNA分子：信使RNA（mRNA），可被翻译成蛋白质；以及非信使RNA，它们在RNA水平上发挥作用，不作为翻译模板。
我们从拟南芥中构建了一个专门的cDNA文库，以研究植物中大小为50 - 500 nt的小非信使RNA（snmRNA）群体。从该文库中，我们鉴定出140个新型snmRNA候选物，并研究了它们的表达、丰度和发育调控。基于保守的序列和结构基序，104种snmRNA物种可被归为已知RNA类别的新成员（称为I类snmRNA），即小核仁RNA（snoRNA）、7SL RNA、U snRNA以及一种类似tRNA的RNA。首次在一种植物物种中鉴定出39个H/ACA盒snoRNA的新成员。其余36个snmRNA候选物（称为II类snmRNA）中，不存在能够将其归为已知RNA类别的序列或结构基序。这些RNA根据它们在拟南芥基因组上的位置进行分类。其中，29种snmRNA物种位于基因间区域，3种位于蛋白质编码基因的内含子序列中，4个snmRNA候选物来自注释的开放阅读框。令人惊讶的是，II类snmRNA候选物中有15种被证明是组织特异性表达的，而12种由线粒体或叶绿体基因组编码。
我们的研究在植物拟南芥中鉴定出140个小非信使RNA物种的新候选物，从而为它们的功能分析奠定了基础。
