BASE-PAIRING BETWEEN U3 AND THE PRE-RIBOSOMAL-RNA IS REQUIRED FOR 18S RIBOSOMAL-RNA SYNTHESIS
BASE-PAIRING BETWEEN U3 AND THE PRE-RIBOSOMAL-RNA IS REQUIRED FOR 18S RIBOSOMAL-RNA SYNTHESIS
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DOI：
10.1002/j.1460-2075.1995.tb00109.x
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发表时间：
1995-09-01
期刊：
影响因子：
11.4
通讯作者：
TOLLERVEY, D
中科院分区：
文献类型：
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作者：
BELTRAME, M;TOLLERVEY, D
核仁是真核细胞中前核糖体 RNA (pre-rRNA) 合成和加工的场所，含有许多小核仁 RNA (snoRNA)。酵母 U3 snoRNA 是从较大前体加工 18S rRNA 所必需的，并且包含与前 rRNA 互补的区域。 pre-rRNA 中的取代突变破坏了这种碱基配对潜力，是致命的，并阻止 18S rRNA 的合成。这些突变的 pre-rRNA 在加工过程中表现出缺陷，与 U3 snoRNP 成分的遗传耗竭的影响非常相似。携带补偿突变的 U3 snoRNA 的共表达使突变的 pre-rRNA 能够支持活力并高水平合成 18S rRNA。被外部转录间隔区突变阻断的前rRNA加工步骤在很大程度上通过补偿性U3突变体的表达得以恢复。因此，前 rRNA 加工需要 snoRNA 和底物之间的直接碱基配对。因此，与底物的碱基配对是参与 mRNA 和 rRNA 成熟的小 RNA 的共同特征。
The nucleolus, the site of pre-ribosomal RNA (pre-rRNA) synthesis and processing in eukaryotic cells, contains a number of small nucleolar RNAs (snoRNAs). Yeast U3 snoRNA is required for the processing of 18S rRNA from larger precursors and contains a region complementary to the pre-rRNA. Substitution mutations in the pre-rRNA which disrupt this base pairing potential are lethal and prevent synthesis of 18S rRNA, These mutant pre-rRNAs show defects in processing which closely resemble the effects of genetic depletion of components of the U3 snoRNP. Co-expression of U3 snoRNAs which carry compensatory mutations allows the mutant pre-rRNAs to support viability and synthesize 18S rRNA at high levels. Pre-rRNA processing steps which are blocked by the external transcribed spacer region mutations are largely restored by expression of the compensatory U3 mutants. Pre-rRNA processing therefore requires direct base pairing between snoRNA and the substrate. Base pairing with the substrate is thus a common feature of small RNAs involved in mRNA and rRNA maturation.