Trypanosoma brucei spliced leader RNA maturation by the cap 1 2'-O-ribose methyltransferase and SLA1 H/ACA snoRNA pseudouridine synthase complex.
Trypanosoma brucei spliced leader RNA maturation by the cap 1 2'-O-ribose methyltransferase and SLA1 H/ACA snoRNA pseudouridine synthase complex.
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布氏锥虫通过 cap 1 2-O-核糖甲基转移酶和 SLA1 H/ACA snoRNA 假尿苷合酶复合物剪接前导 RNA 成熟。
DOI：
10.1128/mcb.01496-08
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发表时间：
2009
影响因子：
5.3
通讯作者：
Campbell,DavidA
中科院分区：
文献类型：
--
作者：
Zamudio,JesseR;Mittra,Bidyottam;Chattopadhyay,Arnab;Wohlschlegel,JamesA;Sturm,NancyR;Campbell,DavidA
鞭毛体动质体通过反式剪接将一个39个核苷酸的剪接前导序列（SL）连接到多顺反子RNA前体的蛋白质编码区上游。SL修饰包括前四个核苷酸的帽2′-O-核糖甲基化和尿嘧啶28处的假尿苷（pseudouridine，pseudouridine）形成。在布氏锥虫中，TbMTr 1对第一个转录的核苷酸或cap 1进行2′-O-核糖甲基化。我们报告了SL RNA加工复合物的表征与TbMTr 1和SLA 1 H/ACA小核仁核糖核蛋白（snoRNP）颗粒，指导SL E28的形成。TbMTr 1是一种高分子量复合物，包含H/ACA snoRNP的四个保守核心蛋白、一种动质体特异性蛋白命名的甲基转移酶相关蛋白（TbMTAP）和SLA 1 snoRNA。TbMTAP无效系是可行的，但在帽甲基化、3′-末端成熟和β 28形成中具有降低的SL RNA加工效率。TbMTAP是TbMTr 1和SLA 1 snoRNP之间的关联所必需的，但不影响U1小核RNA甲基化。TbMTAP-无效系的mRNA群体中复杂的甲基化谱表明对cap 4甲基化的额外影响。TbMTr 1复合物使SLA 1 H/ACA snoRNP特异化，以有效处理SL RNA底物上的多种修饰。
Kinetoplastid flagellates attach a 39-nucleotide spliced leader (SL) upstream of protein-coding regions in polycistronic RNA precursors throughtranssplicing. SL modifications include cap 2′-O-ribose methylation of the first four nucleotides and pseudouridine (ψ) formation at uracil 28. InTrypanosoma brucei, TbMTr1 performs 2′-O-ribose methylation of the first transcribed nucleotide, or cap 1. We report the characterization of an SL RNA processing complex with TbMTr1 and the SLA1 H/ACA small nucleolar ribonucleoprotein (snoRNP) particle that guides SL ψ28formation. TbMTr1 is in a high-molecular-weight complex containing the four conserved core proteins of H/ACA snoRNPs, a kinetoplastid-specific protein designatedmethyltransferase-associatedprotein (TbMTAP), and the SLA1 snoRNA. TbMTAP-null lines are viable but have decreased SL RNA processing efficiency in cap methylation, 3′-end maturation, and ψ28formation. TbMTAP is required for association between TbMTr1 and the SLA1 snoRNP but does not affect U1 small nuclear RNA methylation. A complex methylation profile in the mRNA population of TbMTAP-null lines indicates an additional effect on cap 4 methylations. The TbMTr1 complex specializes the SLA1 H/ACA snoRNP for efficient processing of multiple modifications on the SL RNA substrate.