Prieto-Diez, S. | Search bioRxiv

bioRxiv2026

eIF5A is an indispensable protein for eukaryotic cells

eIF5A is an evolutionarily conserved protein found in all eukaryotes, and in Archaea and bacteria. It functions as a translation factor promoting ribosomal elongation, and it can also bind to genes in the nucleus and to mRNA. eIF5A is encoded by two paralogous genes in most eukaryotes, with one copy (TIF51A in yeast and EIF5A1 in humans) highly expressed and essential, and the other (TIF51B in yeast and EIF5A2 in humans) repressed in most cells and conditions. eIF5A is linked to viral infection, aging, diabetes and neurodevelopmental disorders. Whilst derepression of the duplicated silent gene EIF5A2 is associated with several cancers, promoting metastasis. To expand our knowledge of eIF5As function, we searched for suppressors of yeast temperature-sensitive mutants of TIF51A, which cannot grow at restrictive temperature. All suppressors contained mutations in the transcriptional repressors Rox1 and Mot3, resulting in the upregulation of the paralogous gene TIF51B. Next, we searched for suppressors of TIF51A temperature-sensitive mutants in yeast lacking the TIF51B gene. The frequency of suppression was 20-times lower and all suppressors were revertants or contained intragenic mutations in the Tif51A protein that conferred stability. Our results suggest that the duplicated eIF5A gene serves as a non-conventional backup system that rescues mutations in the first copy, but acting at the population level. Furthermore, our results expand our understanding of the repression mechanisms that keep the second eIF5A gene silent. Lastly, our results demonstrate that eIF5A is an indispensable protein in eukaryotic cells, whose function cannot be substituted by mutations in other proteins or pathways. Article summaryeIF5A is an evolutionary conserved protein encoded by two paralogous genes in eukaryotes: one highly expressed and essential, and the other silent. eIF5A promotes translation elongation, and its deficiency is linked to diabetes, aging and neurodevelopmental disorders; while derepression of the silent gene promotes metastatic cancers. We isolated suppressors of conditional mutants of the first eIF5A gene in yeast cells. Suppressors either up-regulated the second eIF5A gene or reverted first copy mutations, restoring eIF5A protein levels and survival. Our work deepens our understanding of the eIF5A paralogue gene repression, and demonstrates that eIF5A is an indispensable protein for eukaryotic cells.

genetics↗

bioRxiv2025

eIF5A coordinates the transcription and translation of its target genes

Maintaining balanced cellular protein levels requires precise control of gene expression and effective coordination between the various stages of the process, from transcription to translation. In recent years, several components of the translation apparatus have been found in the nuclei of various eukaryotes, where they regulate transcription, mRNA processing or export, thereby integrating different stages of gene expression. eIF5A is an essential and evolutionarily conserved translation elongation factor that is involved in viral infection and in the development of diseases such as cancer and neurodevelopmental disorders. eIF5A promotes translation elongation by binding to ribosomes that stall at codons encoding problematic amino acids for peptide bond formation, such as consecutive prolines, also known as polyproline motifs. Although eIF5A shuttles between the nucleus and cytoplasm, its specific nuclear roles remain poorly defined. Here, we demonstrate that nuclear yeast eIF5A binds to chromatin and represses gene transcription by preventing the binding of RNA polymerase II. Importantly, chromatin binding and transcriptional repression by eIF5A have a higher impact on genes encoding its own translational targets. The presence of polyproline motifs in genes imposes both translation and transcriptional control by eIF5A. Furthermore, eIF5As active engagement in cytoplasmic translation is necessary for its role in repressing transcription. Our results suggest that eIF5A coordinates gene expression by promoting the cytoplasmic translation of specific genes while repressing their transcription in the nucleus, thus ensuring efficient final protein synthesis. Significance StatementOur study provides genome-wide and gene-specific evidence supporting the role of the translation elongation factor eIF5A in transcription. eIF5A is essential in eukaryotes, facilitating the translation of mRNAs encoding stretches of problematic amino acids, such as consecutive prolines. Through its role in the synthesis of specific proteins, eIF5A has been linked to development and different diseases, including cancer and diabetes. We have now discovered that eIF5A also controls the transcription of its translation target genes and this effect is driven by the presence of eIF5A-dependent motifs at their sequences. In the nucleus, eIF5A binds to specific genes and attenuates the binding of RNA polymerase II. By negatively regulating transcription and positively regulating translation, eIF5A coordinates gene expression, fine-tuning protein levels.

molecular biology↗