Two mutant forms of the S1/TPR-containing protein Rrp5p affect the 18S rRNA synthesis in Saccharomyces cerevisiae
Two mutant forms of the S1/TPR-containing protein Rrp5p affect the 18S rRNA synthesis in Saccharomyces cerevisiae
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DOI：
10.1017/s1355838298981511
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发表时间：
1998-12-01
期刊：
影响因子：
4.5
通讯作者：
Hermann-Le Denmat, S
中科院分区：
文献类型：
--
作者：
Torchet, C;Jacq, C;Hermann-Le Denmat, S
酵母Rrp 5 p的遗传缺失导致18 S和5.8S核糖体RNA的合成缺陷（Venema J，Tollervey D. 1996. EMBO J 15：5701-5714）。我们已经分离了RRP 5基因的遗传方法，旨在选择干扰蛋白质输入线粒体的酵母因子。在这里，我们描述了一个显着的特点Rrp 5 p的氨基酸序列，即存在12个假定的S1 RNA结合基序和7个tetratricopeptide repeats（TPR）基序。我们构建了RRP 5基因的两个条件性温度敏感等位基因，并分析了它们相关的rRNA加工缺陷。首先，产生了一个功能性的“二分基因”，揭示了蛋白质的S1和TPR部分可以相互独立地起作用。我们还在TPR单元中产生了两个氨基酸缺失：1（rrp 5 Δ 6等位基因）。Rrp 5 p的两种突变形式显示出在18 S rRNA合成中引起缺陷，而对5.8S rRNA产生没有可检测的影响。然而，在每种情况下，rRNA加工途径受到不同的影响。有趣的是，ROK 1基因，像RRP 5一样，先前在筛选具有snR 10缺失的合成致死突变中分离，在此被鉴定为rrp 5 Delta 6温度敏感等位基因的高拷贝抑制基因。ROK 1也作为一个低拷贝抑制因子，但不能绕过RRP 5的细胞需求。此外，我们表明，抑制Rok 1 p假定的RNA解旋酶拯救18 S rRNA合成缺陷所造成的rrp 5三角洲6突变。
The genetic depletion of yeast Rrp5p results in a synthesis defect of both 18S and 5.8S ribosomal RNAs (Venema J, Tollervey D. 1996. EMBO J 15:5701-5714). We have isolated the RRP5 gene in a genetic approach aimed to select for yeast factors interfering with protein import into mitochondria. We describe here a striking feature of Rrp5p amino acid sequence, namely the presence of twelve putative S1 RNA-binding motifs and seven tetratricopeptide repeats (TPR) motifs. We have constructed two conditional temperature-sensitive alleles of RRP5 gene and analyzed them for associated rRNA-processing defects. First, a functional "bipartite gene" was generated revealing that the S1 and TPR parts of the protein can act independently of each other. We also generated a two amino acid deletion in TPR unit: 1 (rrp5 Delta 6 allele). The two mutant forms of Rrp5p were shown to cause a defect in 18S rRNA synthesis with no detectable effects on 5.8S rRNA production. However, the rRNA processing pathway was differently affected in each case. Interestingly, the ROK1 gene which, like RRP5, was previously isolated in a screen for synthetic lethal mutations with snR10 deletion, was here identified as a high copy suppressor of the rrp5 Delta 6 temperature-sensitive allele. ROK1 also acts as a low copy suppressor but cannot bypass the cellular requirement for RRP5. Furthermore, we show that suppression by the Rok1p putative RNA helicase rescues the 18S rRNA synthesis defect caused by the rrp5 Delta 6 mutation.