Tryptophan plays a central role in yeast’s tolerance to isobutanol
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA733673 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR14687200.fastq.gz | Fastqsanger.gz | |||
| SRR14687201.fastq.gz | Fastqsanger.gz | |||
| SRR14687202.fastq.gz | Fastqsanger.gz | |||
| SRR14687203.fastq.gz | Fastqsanger.gz | |||
| SRR14687204.fastq.gz | Fastqsanger.gz |
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Project description:Isobutanol is considered a potential biofuel and can be produced by genetically modified microorganisms. Saccharomyces cerevisiae inherently produces isobutanol through valine intermediate(s), so it serves as a good host. However, isobutanol's toxicity remains a key obstacle for bioproduction. In our study, we first used image recognition to screen the colony growth of a yeast gene deletion library and inferred that genes involved in tryptophan biosynthesis, ubiquitination, and the pentose phosphate pathway (PPP) contribute to isobutanol tolerance. The importance of tryptophan in yeast's tolerance to isobutanol was confirmed by the recovery of isobutanol tolerance in a tryptophan biosynthesis defective strain by adding exogenous tryptophan. Transcriptomic analysis revealed that amino acid biosynthesis- and transportation-related genes in a tryptophan biosynthesis defective host were up regulated under conditions such as nitrogen starvation. This may explain why ubiquitination for protein degradation was involved for the protein turnover. PPP metabolites and vitamin B1/B6 may serve as precursors and cofactors in tryptophan biosynthesis to enhance isobutanol tolerance. Furthermore, the tolerance mechanism may also be linked to tryptophan metabolism, including the kynurenine pathway and nicotinamide adenine dinucleotide biosynthesis. Both pathways are responsible for cellular redox balance and antioxidative ability and figured out that tryptophan may play a crucial role on isobutanol tolerance. Our study highlights the central role of tryptophan in yeast's isobutanol tolerance and offers new clues for engineering a yeast host with strong isobutanol tolerance.
2021-10-20 | GSE175794 | GEO
Project description:BACKGROUND:Isobutanol is a promising next generation biofuel with demonstrated high yield microbial production, but the toxicity of this molecule reduces fermentation volumetric productivity and final titers. Organic solvent tolerance is a complex, multigenic phenotype that has been recalcitrant to rational engineering approaches. We apply experimental evolution followed by genome resequencing and a gene expression study to elucidate genetic bases on adaptation to exogenous isobutanol stress. RESULTS:The adaptations acquired in our evolved lineages exhibit antagonistic pleiotropy between minimal and rich medium, and appear to be specific to the effects of longer chain alcohols. By examining genotypic adaptation in multiple independent lineages, we find evidence of parallel evolution in hfq, mdh, acrAB, gatYZABCD, and rph genes. Many isobutanol tolerant lineages show reduced rpoS activity, perhaps related to mutations in hfq or acrAB. Consistent with the complex, multigenic nature of solvent tolerance, we observe adaptations in a diversity of cellular processes. Many adaptations appear to involve epistasis between different mutations, implying a rugged fitness landscape for isobutanol tolerance. We observe a trend of evolution targeting post-transcriptional regulation and high centrality nodes of biochemical networks. Collectively, the genotypic adaptations we observe suggest mechanisms of adaptation to isobutanol stress based on remodelling the cell envelope and surprisingly, stress response attenuation. CONCLUSIONS:We have discovered a set of genotypic adaptations that confer increased tolerance to exogenous isobutanol stress. Our results are immediately useful to efforts to engineer more isobutanol tolerant host strains of E. coli for isobutanol production. We suggest that rpoS and post-transcriptional regulators, such as hfq, RNA helicases, and sRNAs may be interesting mutagenesis targets for futurue global phenotype engineering. Two strains (WT strain and G3.2 mutant strain), each with two culture conditions (with and without isobutanol in medium). Three biological replicates for each strain/culture condition. Twelve samples in total.
2010-08-10 | E-GEOD-23526 | biostudies-arrayexpress
Project description:BACKGROUND:Isobutanol is a promising next generation biofuel with demonstrated high yield microbial production, but the toxicity of this molecule reduces fermentation volumetric productivity and final titers. Organic solvent tolerance is a complex, multigenic phenotype that has been recalcitrant to rational engineering approaches. We apply experimental evolution followed by genome resequencing and a gene expression study to elucidate genetic bases on adaptation to exogenous isobutanol stress. RESULTS:The adaptations acquired in our evolved lineages exhibit antagonistic pleiotropy between minimal and rich medium, and appear to be specific to the effects of longer chain alcohols. By examining genotypic adaptation in multiple independent lineages, we find evidence of parallel evolution in hfq, mdh, acrAB, gatYZABCD, and rph genes. Many isobutanol tolerant lineages show reduced rpoS activity, perhaps related to mutations in hfq or acrAB. Consistent with the complex, multigenic nature of solvent tolerance, we observe adaptations in a diversity of cellular processes. Many adaptations appear to involve epistasis between different mutations, implying a rugged fitness landscape for isobutanol tolerance. We observe a trend of evolution targeting post-transcriptional regulation and high centrality nodes of biochemical networks. Collectively, the genotypic adaptations we observe suggest mechanisms of adaptation to isobutanol stress based on remodelling the cell envelope and surprisingly, stress response attenuation. CONCLUSIONS:We have discovered a set of genotypic adaptations that confer increased tolerance to exogenous isobutanol stress. Our results are immediately useful to efforts to engineer more isobutanol tolerant host strains of E. coli for isobutanol production. We suggest that rpoS and post-transcriptional regulators, such as hfq, RNA helicases, and sRNAs may be interesting mutagenesis targets for futurue global phenotype engineering.
2010-08-10 | GSE23526 | GEO
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Project description:[original title] Tissue-specific silencing of C2TA reveals the autonomous role of medullary thymic epithelial cells in central CD4 T cell tolerance. Medullary thymic epithelial cells (mTECs) serve an essential function in central tolerance through expressing peripheral tissue-antigens. Because these antigens may be transferred to and presented by Dendritic Cells, it is unclear whether, besides being an ‘antigen reservoir’, mTECs also fulfill a critical antigen presenting cellfunction. We found that reducing MHC class II-levels on mTECs through transgenic expression of a C2TA-specific ‘designer miRNA’ resulted in an enlarged polyclonal CD4 single-positive compartment. Less CD4+ thymocytes specific for model-antigens expressed in mTECs were deleted, whereas more antigen-specific Foxp3+ regulatory T cells (Treg) emerged. Our data suggest a substantial autonomous contribution of mTECs to both dominant and recessive mechanisms of CD4 T cell tolerance and support an avidity model of Treg development versus deletion.
2010-02-11 | GSE20276 | GEO
Project description:Redox-sensitive bZIP68 plays a role in balancing stress tolerance with growth in Arabidopsis
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Project description:This work was primarily focused on removing the main bottleneck for isobutanol production which is the toxicity of isobutanol towards its host and the major reason for its low-level production. Recently, there have been many reports where people have tried various strategies including continuous in-situ product removal from the bioreactor which led to a significant increase in the final product titers. Clearly, it is the intrinsic tolerance levels of the host which decides the end product titers. Importantly, if the host microbe can originally tolerate higher concentrations of toxin (here isobutanol) then it is likely to have a better potential for further improvement of tolerance levels. In our work, we tried to enhance the isobutanol tolerance of wild type NZ9000 using continuous culture. We used the principle of adaptive laboratory evolution to enhance the natural tolerance ability (0.8% isobutanol) of the wild type strain. The strain was cultivated for more than 60 days (>250 generations), while increasing the selection pressure (here isobutanol) gradually in the feed. This finally led to the strain that showed exceptionally higher tolerance (4%) for isobutanol. Transcriptomic analysis also showed fluctuations in gene expression levels from a wide range of categories, precluding any attempt to reverse engineer this phenotype.
2020-07-08 | GSE107996 | GEO
Project description:hMTR4 plays a central role in creating balanced nuclear RNA pools for degradation and export
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Project description:Medullary thymic epithelial cells (mTECs) are essential for the establishment of self-tolerance in T cells. Promiscuous gene expression by a subpopulation of mTECs regulated by nuclear protein Aire contributes to the display of self-genomic products to newly generated T cells. Recent reports have highlighted additional self-antigen-displaying mTEC subpopulations; namely, Fezf2-expressing mTECs and a mosaic of self-mimetic mTECs including thymic tuft cells. In addition, a functionally different subset of mTECs produces chemokine CCL21 that attracts developing thymocytes to the medullary region. Here we report that CCL21+ mTECs and Aire+ mTECs non-redundantly cooperate to direct self-tolerance to prevent autoimmune pathology by optimizing the deletion of self-reactive T cells and the generation of regulatory T cells. We also detected a cooperation for self-tolerance between Aire and Fezf2, which unexpectedly regulates thymic tuft cells. Our results indicate an indispensable interplay among functionally diverse mTECs for the establishment of central self-tolerance.
2024-03-08 | GSE243180 | GEO
Project description:While direct allorecognition underpins both solid organ allograft rejection and tolerance induction, the specific molecular targets of most directly-alloreactive CD8+ T cells have not been defined. In this study, we used a combination of genetically-engineered MHC I constructs, mice with a hepatocyte-specific mutation in the class I antigen-presentation pathway and immunopeptidomic analysis to provide definitive evidence for the contribution of the peptide cargo of allogeneic MHC I molecules to transplant tolerance induction. We established a systematic approach for the discovery of directly-recognised pMHC epitopes, and identified 17 strongly immunogenic H-2Kb-associated peptides recognised by CD8+ T cells from B10.BR (H-2k) mice, 13 of which were also recognised by BALB/c (H-2d) mice. As few as five different tetramers used together were able to identify almost 40% of alloreactive T cells within a polyclonal population. To our knowledge, this represents the first example of such an approach in the context of direct allorecognition.
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