Functional base-pairing interaction between highly conserved elements of U3 small nucleolar RNA and the small ribosomal subunit RNA
Functional base-pairing interaction between highly conserved elements of U3 small nucleolar RNA and the small ribosomal subunit RNA
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DOI：
10.1006/jmbi.1996.0346
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发表时间：
1996-06-21
影响因子：
5.6
通讯作者：
Hughes, JMX
中科院分区：
文献类型：
--
作者：
Hughes, JMX
U3 核仁 RNA 具有非常广泛的系统分布，从真核生物延伸到古细菌。它通过一种至今未知但涉及与前 rRNA 碱基配对的机制在小亚基 (SSU) rRNA 的成熟中发挥作用。 U3 最保守的部分位于 5' 端的 30 个核苷酸内，但尚未提出该结构域的功能。该结构域内的元件与 SSU rRNA 中高度保守的序列互补，成熟形式的 SSU rRNA 折叠成普遍保守的假结。互补性的本质表明了 U3 功能的一种新机制，其中 U3 促进了假结的正确折叠。广泛的系统发育比较提供了令人信服的证据来支持相互作用，因为发生了显着的互补变化，特别是在古细菌 Sulfolobus 中，它维持碱基配对。酵母 U3 中旨在破坏碱基配对的碱基取代突变表明这种相互作用可能是必需的。其中包括冷敏感性突变，其表现出与 U3 耗竭相似的表型，但不会损害 5' ETS 内发生的 AO 加工步骤。这些表型与SSU前体的不稳定以及5'ETS/18S边界处的加工步骤A1和ITS1内的A2的部分损伤一致。 (C) 1996 学术出版社有限公司
The U3 nucleolar RNA has a remarkably wide phyletic distribution extending from the Eukarya to the Archaea. It functions in maturation of the small subunit (SSU) rRNA through a mechanism which is as yet unknown but which involves base-pairing with pre-rRNA. The most conserved part of U3 is within 30 nucleotides of the 5' end, but as yet no function for this domain has been proposed. Elements within this domain are complementary to highly conserved sequences in the SSU rRNA which, in the mature form, fold into a universally conserved pseudoknot. The nature of the complementarity suggests a novel mechanism for U3 function whereby U3 facilitates correct folding of the pseudoknot. Wide phylogenetic comparison provides compelling evidence in support of the interaction in that significant complementary changes have taken place, particularly in the archaeon Sulfolobus, which maintain the base-pairing. Base-substitution mutations in yeast U3 designed to disrupt the base-pairing indicate that the interaction is probably essential. These include cold-sensitivity mutations which exhibit phenotypes similar to U3-depletion, but without impairment of the AO processing step, which occurs within the 5' ETS. These phenotypes are consistent with the destabilization of SSU precursors and partial impairment of the processing steps Al, at the 5' ETS/18 S boundary, and A2, within the ITS1. (C) 1996 Academic Press Limited