The yeast La related protein Slf1p is a key activator of translation during the oxidative stress response.
The yeast La related protein Slf1p is a key activator of translation during the oxidative stress response.
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DOI：
10.1371/journal.pgen.1004903
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发表时间：
2015-01
期刊：
影响因子：
4.5
通讯作者：
Grant CM
中科院分区：
文献类型：
--
作者：
Kershaw CJ;Costello JL;Castelli LM;Talavera D;Rowe W;Sims PF;Ashe MP;Hubbard SJ;Pavitt GD;Grant CM
RNA结合蛋白控制mRNA子集翻译的机制尚不清楚。Slf1p和Sro9p是真核生物中保守的RNA结合蛋白超家族的成员，它们都是含有La基序的蛋白质。对这两种酵母蛋白的RIP-Seq分析鉴定了重叠和不同的mRNA靶标组，包括高度翻译的mRNA，如编码核糖体蛋白的mRNA。在Sclerell中，slf 1 Δ和sro 9 Δ突变株的转录组分析表明，在每个因子丢失后，相似功能类别的mRNA的基因表达发生了改变。SLF 1的缺失对转录组有更大的影响，特别是揭示了参与氧化应激反应的基因的变化。slf1 Δ细胞对氧化剂更敏感，对氧化应激细胞的RIP-Seq分析富集了编码抗氧化剂和氧化耐受性所需的其他蛋白质的Slf1p靶标。为了在蛋白质水平上量化这些影响，我们使用无标记质谱法比较了氧化应激后野生型和slf1 Δ菌株的蛋白质组。该分析鉴定了几种蛋白质，其通常响应于过氧化氢而被诱导，但在slf 1 Δ突变体中这种增加被减弱。重要的是，编码这些靶点的大量mRNA也被鉴定为Slf1p-mRNA靶点。我们发现，Slf1p仍然与几个翻译核糖体过氧化氢应激后，Slf1p共免疫沉淀核糖体和eIF4E/eIF4G/Pab1p的“闭环”复合物的成员表明，Slf1p与积极翻译的mRNA相互作用后的压力。最后，SLF1的突变分析揭示了一个新的核糖体相互作用域在Slf1p，独立于其RNA结合La基序。总之，我们的研究结果表明，Slf1p介导的翻译反应，通过mRNA特异性的翻译控制氧化应激。所有生物都必须对外部环境的变化做出反应，例如暴露于不同的压力。基因组序列和后基因组技术的可用性，使这些适应性反应的分析在分子水平上的基因表达谱的改变。然而，相对较少的研究集中在细胞如何调节mRNA翻译成蛋白质，以响应压力，尽管它在基因表达途径中的基本作用。在这项研究中，我们表明，以前确定的RNA结合蛋白称为Slf1p在mRNA特异性调节翻译在氧化应激条件下起着重要作用，是必要的，以促进应激反应的mRNA的翻译。这种蛋白质是所谓的“La相关”蛋白质家族的成员，虽然它们在整个进化过程中是保守的，但尚未得到很好的表征。已知暴露于氧化剂会导致蛋白质合成的普遍下调，尽管许多应激反应蛋白能够克服这种抑制并通过迄今未知的机制在应激后增加其蛋白质水平。我们的实验提供了一种可能的解释，因为它们表明Slf1p在增强许多这些蛋白质的翻译中起着关键作用，包括许多细胞应激反应所必需的蛋白质。
The mechanisms by which RNA-binding proteins control the translation of subsets of mRNAs are not yet clear. Slf1p and Sro9p are atypical-La motif containing proteins which are members of a superfamily of RNA-binding proteins conserved in eukaryotes. RIP-Seq analysis of these two yeast proteins identified overlapping and distinct sets of mRNA targets, including highly translated mRNAs such as those encoding ribosomal proteins. In paralell, transcriptome analysis of slf1Δ and sro9Δ mutant strains indicated altered gene expression in similar functional classes of mRNAs following loss of each factor. The loss of SLF1 had a greater impact on the transcriptome, and in particular, revealed changes in genes involved in the oxidative stress response. slf1Δ cells are more sensitive to oxidants and RIP-Seq analysis of oxidatively stressed cells enriched Slf1p targets encoding antioxidants and other proteins required for oxidant tolerance. To quantify these effects at the protein level, we used label-free mass spectrometry to compare the proteomes of wild-type and slf1Δ strains following oxidative stress. This analysis identified several proteins which are normally induced in response to hydrogen peroxide, but where this increase is attenuated in the slf1Δ mutant. Importantly, a significant number of the mRNAs encoding these targets were also identified as Slf1p-mRNA targets. We show that Slf1p remains associated with the few translating ribosomes following hydrogen peroxide stress and that Slf1p co-immunoprecipitates ribosomes and members of the eIF4E/eIF4G/Pab1p ‘closed loop’ complex suggesting that Slf1p interacts with actively translated mRNAs following stress. Finally, mutational analysis of SLF1 revealed a novel ribosome interacting domain in Slf1p, independent of its RNA binding La-motif. Together, our results indicate that Slf1p mediates a translational response to oxidative stress via mRNA-specific translational control. All organisms must respond to changes in their external environment such as exposure to different stresses. The availability of genome sequences and post-genomic technologies has enabled the analysis of these adaptive responses at the molecular level in terms of altered gene expression profiles. However, relatively few studies have focused on how cells regulate the translation of mRNA into protein in response to stress, despite its fundamental role in gene expression pathways. In this study, we show that a previously identified RNA-binding protein called Slf1p plays a major role in mRNA-specific regulation of translation during oxidative stress conditions and is necessary to promote the translation of stress-responsive mRNAs. This protein is a member of the so-called “La-related” family of proteins that have not been well characterized, although they are conserved throughout evolution. Exposure to oxidants is known to cause a general down-regulation of protein synthesis, although many stress response proteins are able to overcome this inhibition and increase their protein levels following stress by as yet unknown mechanisms. Our experiments offer one possible explanation, as they show that Slf1p plays a critical role in enhancing translation of many of these proteins, including many that are necessary for the cellular stress response.
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DOI：
10.1073/pnas.211266898
发表时间：
2001-10-09
影响因子：
11.1
作者：
Sengupta, J;Agrawal, RK;Frank, J
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影响因子：
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DOI：
10.1016/j.bbagrm.2010.01.011
发表时间：
2010-05
影响因子：
4.7
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