Under high boron (B) conditions, nodulin 26‐like intrinsic protein 5;1 (NIP5;1) mRNA, a boric acid channel, is destabilized to avoid excess B entry into roots of Arabidopsis thaliana. In this regulation, the minimum upstream open reading frame (uORF), AUGUAA, in its 5′‐untranslated region (5′‐UTR) is essential, and high B enhances ribosome stalling at AUGUAA and leads to suppression of translation and mRNA degradation. This B‐dependent AUGUAA‐mediated regulation occurs also in animal transient expression and reticulocyte lysate translation systems. Thus, uncovering the ubiquitousness of B‐dependent unique regulation is important to reveal the evolution of translational regulation. In the present study, we examined the regulation in Saccharomyces cerevisiae. Reporter assay showed that in yeast, carrying ATGTAA in 5′‐UTR of NIP5;1 upstream of the reporter gene, the relative reporter activities were reduced significantly under high B conditions compared with control, whereas deletion of ATGTAA abolished such responses. This suggests that AUGUAA mediates B‐dependent regulation of translation in Saccharomyces cerevisiae. Moreover, the deletion of ATGTAA resulted in up to 10‐fold increase in general reporter activities indicating the suppression effect of AUGUAA on translation of the main ORF. Interestingly, mRNA level of the reporter gene was not affected by B in both yeast cells with and without AUGUAA. This finding reveals that in yeast, unlike the case in plants, mRNA degradation is not associated with AUGUAA regulation. Together, results suggest that B‐dependent AUGUAA‐mediated translational regulation is common among eukaryotes.

中文翻译：

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酵母中通过 AUGUAA 序列对翻译的硼依赖性调节

在高硼 (B) 条件下，nodulin 26 样内在蛋白 5;1 ( NIP5;1 ) mRNA，一种硼酸通道，不稳定，以避免过量的 B 进入拟南芥的根部。在该调节中，最小上游开放阅读框 (uORF) AUGUAA 在其 5'-非翻译区 (5'-UTR) 中是必不可少的，高 B 增强了 AUGUAA 的核糖体停滞并导致抑制翻译和 mRNA 降解。这种 B 依赖性 AUGUAA 介导的调节也发生在动物瞬时表达和网织红细胞裂解物翻译系统中。因此，揭示 B 依赖性独特调控的普遍性对于揭示翻译调控的演变非常重要。在本研究中，我们检查了监管酿酒酵母。报告基因检测表明，在酵母中，在NIP5;1上游的NIP5' -UTR 中携带 ATGTAA，与对照相比，在高 B 条件下相对报告基因活性显着降低，而 ATGTAA 的缺失则消除了这种反应。这表明 AUGUAA 介导了酿酒酵母中B 依赖性翻译调节. 此外，ATGTAA 的缺失导致一般报告基因活性增加多达 10 倍，表明 AUGUAA 对主要 ORF 翻译的抑制作用。有趣的是，在有和没有 AUGUAA 的酵母细胞中，报告基因的 mRNA 水平不受 B 的影响。这一发现表明，在酵母中，与植物不同，mRNA 降解与 AUGUAA 调节无关。总之，结果表明 B 依赖性 AUGUAA 介导的翻译调节在真核生物中很常见。