Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China.
Shanxi Key Laboratory of Biotechnology, Taiyuan 030006, China.
Int J Mol Sci. 2024 Feb 1;25(3):1766. doi: 10.3390/ijms25031766.
Programmed ribosomal frameshifting (PRF) exists in all branches of life that regulate gene expression at the translational level. The eukaryotic translation initiation factor 5A (eIF5A) is a highly conserved protein essential in all eukaryotes. It is identified initially as an initiation factor and functions broadly in translation elongation and termination. The hypusination of eIF5A is specifically required for +1 PRF at the shifty site derived from the () in . However, whether the regulation of +1 PRF by yeast eIF5A is universal remains unknown. Here, we found that Sc-eIF5A depletion decreased the putrescine/spermidine ratio. The re-introduction of Sc-eIF5A in yeast eIF5A mutants recovered the putrescine/spermidine ratio. In addition, the Sc-eIF5A depletion decreases +1 PRF during the decoding of retrotransposon mRNA, but has no effect on -1 PRF during the decoding of virus mRNA. The re-introduction of Sc-eIF5A in yeast eIF5A mutants restored the +1 PRF rate of Ty1. The inhibition of the hypusine modification of yeast eIF5A by GC7 treatment or by mutating the hypusination site Lys to Arg caused decreases of +1 PRF rates in the retrotransposon. Furthermore, mutational studies of the frameshifting element support a model where the efficient removal of ribosomal subunits at the first frame 0 stop codon is required for the frameshifting of trailing ribosomes. This dependency is likely due to the unique position of the frame 0 stop codon distance from the slippery sequence of . The results showed that eIF5A is a -regulator of +1 PRF for retrotransposon and could function universally in yeast.
核糖体框架移位（PRF）存在于所有生命分支中，可在翻译水平上调节基因表达。真核翻译起始因子 5A（eIF5A）是一种高度保守的蛋白质，在所有真核生物中都是必需的。它最初被鉴定为起始因子，广泛参与翻译延伸和终止。eIF5A 的Hypusination 对于源自 () 的移码位点的 +1 PRF 是特异性必需的。然而，酵母 eIF5A 对 +1 PRF 的调节是否普遍仍然未知。在这里，我们发现 Sc-eIF5A 耗竭降低了腐胺/亚精胺的比例。在酵母 eIF5A 突变体中重新引入 Sc-eIF5A 恢复了腐胺/亚精胺的比例。此外，Sc-eIF5A 耗竭降低了 retrotransposon mRNA 解码过程中的 +1 PRF，但对 病毒 mRNA 解码过程中的 -1 PRF 没有影响。在酵母 eIF5A 突变体中重新引入 Sc-eIF5A 恢复了 Ty1 的 +1 PRF 率。GC7 处理或突变 Hypusination 位点 Lys 为 Arg 抑制酵母 eIF5A 的 Hypusine 修饰导致 retrotransposon 的 +1 PRF 率降低。此外， 框架移位元件的突变研究支持这样的模型，即第一个 框架 0 终止密码子处核糖体亚基的有效去除是尾随核糖体移位的必需条件。这种依赖性可能是由于框架 0 终止密码子与滑溜溜序列的距离的独特位置所致。结果表明，eIF5A 是 retrotransposon +1 PRF 的负调节剂，可在酵母中普遍发挥作用。
