scholarly journals Impact of stress‐response related transcription factor overexpression on lignocellulosic inhibitor tolerance of Saccharomyces cerevisiae environmental isolates

2020 ◽  
Author(s):  
Jeffrey A. Mertens ◽  
Christopher D. Skory ◽  
Nancy N. Nichols ◽  
Ronald E. Hector
2007 ◽  
Vol 6 (8) ◽  
pp. 1373-1379 ◽  
Author(s):  
Ayako Yamamoto ◽  
Junko Ueda ◽  
Noritaka Yamamoto ◽  
Naoya Hashikawa ◽  
Hiroshi Sakurai

ABSTRACT The heat shock transcription factor Hsf1 of the yeast Saccharomyces cerevisiae regulates the transcription of a set of genes that contain heat shock elements (HSEs) in their promoters and function in diverse cellular processes, including protein folding. Here, we show that Hsf1 activates the transcription of various target genes when cells are treated with oxidizing reagents, including the superoxide anion generators menadione and KO2 and the thiol oxidants diamide and 1-chloro-2,4-dinitrobenzene (CDNB). Similar to heat shock, the oxidizing reagents are potent inducers of both efficient HSE binding and extensive phosphorylation of Hsf1. The inducible phosphorylation of Hsf1 is regulated by the intramolecular domain-domain interactions and affects HSE structure-specific transcription. Unlike the heat shock, diamide, or CDNB response, menadione or KO2 activation of Hsf1 is inhibited by cyclic-AMP-dependent protein kinase (PKA) activity, which negatively regulates the activator functions of other transcriptional regulators implicated in the oxidative stress response. These results demonstrate that Hsf1 is a member of the oxidative stress-responsive activators and that PKA is a general negative regulator in the superoxide anion response.


2009 ◽  
Vol 8 (5) ◽  
pp. 768-778 ◽  
Author(s):  
Xin-Jian He ◽  
KariAn E. Mulford ◽  
Jan S. Fassler

ABSTRACT The bifunctional Saccharomyces cerevisiae Skn7 transcription factor regulates osmotic stress response genes as well as oxidative stress response genes; however, the mechanisms involved in these two types of regulation differ. Skn7 osmotic stress activity depends on the phosphorylation of the receiver domain aspartate, D427, by the Sln1 histidine kinase. In contrast, D427 and the SLN1-SKN7 phosphorelay are dispensable for the oxidative stress response, although the receiver domain is required. The majority of oxidative stress response genes regulated by Skn7 also are regulated by the redox-responsive transcription factor Yap1. It is therefore possible that the nuclearly localized Skn7 does not itself respond to the oxidant but simply cooperates with Yap1 when it translocates to the nucleus. We report here that oxidative stress leads to a phosphatase-sensitive, slow-mobility Skn7 variant. This suggests that Skn7 undergoes a posttranslational modification by phosphorylation following exposure to oxidant. Oxidant-dependent Skn7 phosphorylation was eliminated in strains lacking the Yap1 transcription factor. This suggests that the phosphorylation of Skn7 is regulated by Yap1. Mutations in the receiver domain of Skn7 were identified that affect its oxidative stress function. These mutations were found to compromise the association of Yap1 and Skn7 at oxidative stress response gene promoters. A working model is proposed in which the association of Yap1 with Skn7 in the nucleus is a prerequisite for Skn7 phosphorylation and the activation of oxidative stress response genes.


2019 ◽  
Author(s):  
Meenu Sharma ◽  
V. Verma ◽  
Narendra K Bairwa

AbstractStress 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.


2021 ◽  
Vol 43 (1) ◽  
Author(s):  
Meenu Sharma ◽  
V. Verma ◽  
Narendra K. Bairwa

Abstract Background Stress response is mediated by the transcription of stress-responsive genes. The F-box motif protein Saf1p is involved in SCF-E3 ligase mediated degradation of the adenine deaminase, Aah1p upon nutrient stress. The four transcription regulators, BUR6, MED6, SPT10, SUA7, are listed for SAF1 in the genome database of Saccharomyces cerevisiae. Here in this study, we carried out an in-silico analysis of gene expression and transcription factor databases to understand the regulation of SAF1 expression during stress for hypothesis and experimental analysis. Result An analysis of the GEO profile database indicated an increase in SAF1 expression when cells were treated with stress agents such as Clioquinol, Pterostilbene, Gentamicin, Hypoxia, Genotoxic, desiccation, and heat. The increase in expression of SAF1 during stress conditions correlated positively with the expression of RLM1, encoding the Rlm1p transcription factor. The expression of AAH1 encoding Aah1p, a Saf1p substrate for ubiquitination, appeared to be negatively correlated with the expression of RLM1 as revealed by an analysis of the Yeastract expression database. Based on analysis of expression profile and regulatory association of SAF1 and RLM1, we hypothesized that inactivation of both the genes together may contribute to stress tolerance. The experimental analysis of cellular growth response of cells lacking both SAF1 and RLM1 to selected stress agents such as cell wall and osmo-stressors, by spot assay indicated stress tolerance phenotype similar to parental strain however sensitivity to genotoxic and microtubule depolymerizing stress agents. Conclusions Based on in-silico and experimental data we suggest that SAF1 and RLM1 both interact genetically in differential response to genotoxic and general stressors.


2019 ◽  
Vol 20 (2) ◽  
pp. 100-114 ◽  
Author(s):  
Wei Tang ◽  
Wells A. Thompson

Background: MicroRNAs participate in many molecular mechanisms and signaling transduction pathways that are associated with plant stress tolerance by repressing expression of their target genes. However, how microRNAs enhance tolerance to low temperature stress in plant cells remains elusive. Objective: In this investigation, we demonstrated that overexpression of the rice microRNA528 (OsmiR528) increases cell viability, growth rate, antioxidants content, ascorbate peroxidase (APOX) activity, and superoxide dismutase (SOD) activity and decreases ion leakage rate and thiobarbituric acid reactive substances (TBARS) under low temperature stress in Arabidopsis (Arabidopsis thaliana), pine (Pinus elliottii), and rice (Oryza sativa). Methods: To investigate the potential mechanism of OsmiR528 in increasing cold stress tolerance, we examined expression of stress-associated MYB transcription factors OsGAMYB-like1, OsMYBS3, OsMYB4, OsMYB3R-2, OsMYB5, OsMYB59, OsMYB30, OsMYB1R, and OsMYB20 in rice cells by qRT-PCR. Results: Our experiments demonstrated that OsmiR528 decreases expression of transcription factor OsMYB30 by targeting a F-box domain containing protein gene (Os06g06050), which is a positive regulator of OsMYB30. In OsmiR528 transgenic rice, reduced OsMYB30 expression results in increased expression of BMY genes OsBMY2, OsBMY6, and OsBMY10. The transcript levels of the OsBMY2, OsBMY6, and OsBMY10 were elevated by OsMYB30 knockdown, but decreased by Os- MYB30 overexpression in OsmiR528 transgenic cell lines, suggesting that OsmiR528 increases low temperature tolerance by modulating expression of stress response-related transcription factor. Conclusion: Our experiments provide novel information in increasing our understanding in molecular mechanisms of microRNAs-associated low temperature tolerance and are valuable in plant molecular breeding from monocotyledonous, dicotyledonous, and gymnosperm plants.


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