Three small nucleolar RNAs identified from the spliced leader-associated RNA locus in kinetoplastid protozoans.
Three small nucleolar RNAs identified from the spliced leader-associated RNA locus in kinetoplastid protozoans.
复制标题
从动质体原生动物的剪接前导相关 RNA 位点中鉴定出三种小核仁 RNA。
DOI：
10.1128/mcb.18.8.4409
复制
发表时间：
1998
影响因子：
5.3
通讯作者：
Campbell,DA
中科院分区：
文献类型：
--
作者：
Roberts,TG;Sturm,NR;Yee,BK;Yu,MC;Hartshorne,T;Agabian,N;Campbell,DA
首先在布氏锥虫中鉴定，剪接前导相关（SLA）RNA基因位点现已从动质体利什曼原虫和克氏锥虫中分离。除了T。bruceiSLA RNA，bothL. tarentolae和T. cruziSLA RNA重复单元也分别产生75或76个核苷酸（nt）、92或94 nt以及10450或10350 nt的RNA，每个RNA与先前描述的来自T.布氏杆菌SLARNA基因座细胞分级分离研究将这三种额外的RNA定位于核仁;其中两种转录本中存在盒C/D样元件，表明它们是一类引导rRNA修饰和切割的小核仁RNA（snoRNA）的成员。候选的rRNA-snoRNA相互作用可以在每个含有C/D元件的RNA中的一个结构域中找到。75/76-nt RNA的推定靶位点是小亚基rRNA的高度保守部分，其在L中的保守位置（Gm 1830）含有2′-O-核糖甲基化。tarentolaeand in vertebral脊椎动物. 92/94-nt RNA具有在大亚基rRNA中的保守甲基化位点附近形成碱基对的潜力，该位点对应于布氏锥虫中小rRNA 2的位置Gm 4141。这些数据表明，锥虫不遵守snoRNA介导的甲基化的一般5-bp规则。
First characterized inTrypanosoma brucei, the spliced leader-associated (SLA) RNA gene locus has now been isolated from the kinetoplastidsLeishmania tarentolaeandTrypanosoma cruzi. In addition to theT. bruceiSLA RNA, bothL. tarentolaeandT. cruziSLA RNA repeat units also yield RNAs of 75 or 76 nucleotides (nt), 92 or 94 nt, and ∼450 or ∼350 nt, respectively, each with significant sequence identity to transcripts previously described from theT. bruceiSLA RNA locus. Cell fractionation studies localize the three additional RNAs to the nucleolus; the presence of box C/D-like elements in two of the transcripts suggests that they are members of a class of small nucleolar RNAs (snoRNAs) that guide modification and cleavage of rRNAs. Candidate rRNA-snoRNA interactions can be found for one domain in each of the C/D element-containing RNAs. The putative target site for the 75/76-nt RNA is a highly conserved portion of the small subunit rRNA that contains 2′-O-ribose methylation at a conserved position (Gm1830) inL. tarentolaeand in vertebrates. The 92/94-nt RNA has the potential to form base pairs near a conserved methylation site in the large subunit rRNA, which corresponds to position Gm4141 of small rRNA 2 inT. brucei. These data suggest that trypanosomatids do not obey the general 5-bp rule for snoRNA-mediated methylation.