Genetic Interaction between RLM1 and F-box Motif Encoding gene SAF1 Contributes to Stress Response inSaccharomyces cerevisiae

Stress response is mediated by transcription of stress responsive genes. F-box motif protein Saf1 involves in SCF-E3 ligase mediated degradation of the adenine deaminase, Aah1 upon nutrient stress. Four transcription regulators, BUR6, MED6, SPT10, SUA7, have been reported for SAF1 gene in genome database of Saccharomyces cerevisiae. Here in this study an in-silco analysis of gene expression and transcription factor databases was carried out to understand the regulation of SAF1 gene expression during stress for hypothesis generation and experimental analysis. The GEO profile database analysis showed increased expression of SAF1 gene when treated with clioquinol, pterostilbene, gentamicin, hypoxia, genotoxic, desiccation, and heat stress, in WT cells. SAF1 gene expression in stress conditions correlated positively whereas AAH1 expression negatively with RLM1 transcription factor, which was not reported earlier. Based on analysis of expression profile and regulatory association of SAF1 and RLM1, we hypothesized that inactivation of both the genes may contribute to stress tolerance. The experimental analysis with the double mutant, saf1Δrlm1Δ for cellular growth response to stress causing agents, showed tolerance to calcofluor white, SDS, and hydrogen peroxide. On the contrary, saf1Δrlm1Δ showed sensitivity to MMS, HU, DMSO, Nocodazole, Benomyl stress. Based on in- silico and experimental data we suggest that SAF1 and RLM1 both interact genetically in differential response to genotoxic and general stressors.