Heavy metal sensitivities of gene deletion strains for ITT1 and RPS1A connect their activities to the expression of URE2, a key gene involved in metal detoxification in yeast

Abstract

Heavy metal and metalloid contaminations are among the most concerning types of pollutant in the environment. Consequently, it is important to investigate the molecular mechanisms of cellular responses and detoxification pathways for these compounds in living organisms. To date, a number of genes have been linked to the detoxification process. The expression of these genes can be controlled at both transcriptional and translational levels. In baker’s yeast, Saccharomyces cerevisiae, resistance to a wide range of toxic metals is regulated by glutathione S-transferases. Yeast URE2 encodes for a protein that has glutathione peroxidase activity and is homologous to mammalian glutathione S-transferases. The URE2 expression is critical to cell survival under heavy metal stress. Here, we report on the finding of two genes, ITT1, an inhibitor of translation termination, and RPS1A, a small ribosomal protein, that when deleted yeast cells exhibit similar metal sensitivity phenotypes to gene deletion strain for URE2. Neither of these genes were previously linked to metal toxicity. Our gene expression analysis illustrates that these two genes affect URE2 mRNA expression at the level of translation.

Sensitivity of yeast to lithium chloride connects the activity of YTA6 and YPR096C to translation of structured mRNAs

“…Synthetic genetic analysis for YTA6 and YPR096C was performed in a 384 format as before [17,19,27]. In brief, deletion mutant for query genes in Mat α mating type were crossed to two sets of gene deletion mutants in Mat a mating type.…”

“…Drug sensitivity of mutant strains to a target chemical is an important tool to investigate how a chemical compound affects the cell at the molecular level and pathways influenced by the drug [17,19,35]. While investigating yeast gene deletion mutants that are sensitive to LiCl we identified two gene deletion mutants for YTA6 and YPR096C that showed increased sensitivity to LiCl.…”

“…An nGI can reveal the involvement of genes in compensating parallel pathways. nGI analysis has been used in various investigations to study gene function [17,18,33]. Systematic analysis of GIs in yeast is made possible by its two mating types.…”

Conservation of Translation Initiation Between Prokaryotes and Eukaryotes

“…Despite this detail, there are many cellular mRNAs that have been identified to possess IRES elements, with both mechanisms operating on the same message (Komar and Hatzoglou, 2011b). It is thought that these cellular IRESs possess two major physiological functions; 1) allow for the translation of mRNAs with complex 5' UT Rs under normal physiological conditions, and 2) maintain translation of mRNAs under various (patho)physiological stress conditions (Komar and Hatzoglou, 2011b;Pichon et al, 2012;Moteshareie et al, 2018). As expected, many mRNAs identified to possess an IRES element function to maintain cell homeostasis and play a regulatory role in cell-fate decisions, including transcription factors (HIF-1), oncogenes (c-myc), cell cycle control genes (Cyclin D1) and apoptotic genes (Apaf-1 and Bcl-2) (Stoneley et al, 1998;Coldwell et al, 2000;Lang, Kappel and Goodall, 2002;Sherrill et al, 2004;Shi et al, 2005;Pichon et al, 2012).…”

Functional Genomics in Yeast

“…The baker's yeast, Saccharomyces cerevisiae is a single-cell eukaryotic model organism that has been broadly used, not only to investigate various cell processes and pathways in molecular biology investigations 28,30,31 but also as a model organism of choice in functional genomics, proteomics, and evolutionary genetics [32][33][34][35] . This model organism has a short life cycle, its genomic manipulation is fairly easy, possesses both haploid and diploid life cycles (aids in a number of high-throughput techniques), is the first eukaryote to have its genome sequenced, and genomics and proteomics annotations are available through different databases (SGD; www.yeastgenome.org, and https://yeast.biocyc.org/ 36 ).…”