Expression data for transcriptional engineering mutants capable of L-tyrosine overproduction
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ABSTRACT:
ORGANISM(S): Escherichia coli
PROVIDER: GSE21652 | GEO | 2012/09/04
SECONDARY ACCESSION(S): PRJNA125877
REPOSITORIES: GEO
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Project description:We measured transcriptional changes in four strains M-bM-^@M-^S P2, rpoD3, rpoA14, and rpoA27 - in an effort to understand mechanisms by which L-tyrosine production is positively influenced by the presence of mutant rpoA- and rpoD-encoded transcriptional components. Strains P2, rpoA14, rpoA27, and rpoD3 were grown in 50 ml MOPS minimal medium to an OD600 of approximately 0.4. Triplicates samples of RNA (on three separate days) were then extracted for hybridization onto Affymetrix microarrays.
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Project description:<p>The purpose of the original study was to search for somatic mutations in the tyrosine kinome of serous and clear cell endometrial carcinomas (human). The study was conducted in two phases.</p> <p>Phase 1: A mutation discovery screen, in which ~577 exons encoding the catalytic domains of 86 tyrosine kinases were PCR-amplified and bidirectionally Sanger sequenced from 24 serous, 11 clear cell, and 5 mixed histology endometrial tumors. This was followed by alignment of sequence reads to the human reference sequence and subsequent nucleotide variant calling to identify potential somatic (tumor-specific) mutations. Potential somatic mutations were confirmed by re-amplification and sequencing of the relevant tumor DNA as well as matched non-tumor ("normal") DNA from the same case.</p> <p>Phase 2: A mutation prevalence screen, in which the non-catalytic regions two tyrosine kinase genes, TNK2 and DDR1, were PCR-amplified and sequenced from the 40 discovery screen tumors, and all coding exons of TNK2 and DDR1 were PCR-amplified and sequenced from another 10 clear cell, 21 serous, and 41 endometrioid endometrial tumors, in an effort to identify additional somatic mutations in each gene. Exons encoding the exonuclease domain of POLE were also sequenced to document somatic mutations.</p>
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2022-06-07 | E-MTAB-9099 | biostudies-arrayexpress
Project description:Certain streptomycin resistance mutations (i.e., rpsL and rsmG) result in the overproduction of antibiotics in various actinomycetes. Moreover, rpsL rsmG double-mutant strains show a further increase in antibiotic production. rpsL but not rsmG mutations result in a marked enhancement of oligomycin production in Streptomyces avermitilis and erythromycin production in Saccharopolyspora erythraea, accompanied by increased transcription of a key developmental regulator gene, bldD, in the latter organism.
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Project description:Combinatorial design is an effective strategy to acquire the optimal solution in complex systems. In this study, the combined effects of pathway combination, promoters' strength fine-tuning, copy numbers and integration locus variations caused by δ-integration were explored in Saccharomyces cerevisiae using geranylgeraniol (GGOH) production as an example. Two GGOH biosynthetic pathway branches were constructed. In branch 1, GGOH was converted from isopentenyl pyrophosphate (IPP) and farnesyl diphosphate (FPP). In branch 2, GGOH was derived directly from IPP and dimethylallyl pyrophosphate (DMAPP). Regulated by 10 combinations of 11 diverse promoters, a fusion gene BTS1-ERG20, a heterologous geranylgeranyl diphosphate synthase from Sulfolobus acidocaldarius (GGPPSsa) and an endogenous N-terminal truncated gene 3-hydroxyl-3-methylglutaryl-CoA reductase isoenzyme 1 (tHMGR), were incorporated into yeast by δ-integration, leading to a series of GGOH producing strains with yields ranging from 18.45 mg/L to 161.82 mg/L. The yield was further increased to 437.52 mg/L by optimizing the fermentation medium. Consequently, the GGOH yield reached 1315.44 mg/L in a 5-L fermenter under carbon restriction strategy. Our study not only opens large opportunities for downstream diterpenes overproductions, but also demonstrates that pathway optimization based on combinatorial design is a promising strategy to engineer microbes for overproducing natural products with complex structure.
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Project description:HIV-1 virion production is inefficient in cells derived from mice and other rodents. Inefficient production maps, in part, to a species-specific polymorphism in the cellular gene, CCNT1. In human cells, the HIV-1 Tat protein hijacks the positive transcription elongation factor (p-TEFb) complex, composed of CCNT1 and the cellular kinase CDK9, to promote viral transcript elongation and thereby increasing net viral gene expression and virion production. In mouse cells, Tat-dependent viral transcription is poor, reflecting the inability of Tat to engage p-TEFb because of a species-specific tyrosine residue at position 261 in the mouse ortholog of CCNT1. Humans encode a cysteine at the equivalent position which Tat requires for efficient p-TEFb usage. Here, we used CRISPR/Cas9 genome engineering to substitute the native cysteine with the rodent-encoded tyrosine (C261Y) in the human Jurkat T cell line (E6-1 clone). We derived two independent Jurkat T cell clones with all endogenous CCNT1 encoding the C261Y substitution. In an effort to understand net impacts to cellular and viral gene expression, we compared the transcriptomes of uninfected parental Jurkat T cells (E6-1 clone) to the two derived clones (C1 and C2, CCNT1.C261Y).
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Project description:Genome engineering has become a powerful tool for creating useful strains in research and industry. In this study, we applied singleplex and multiplex genome engineering approaches to construct an E. coli strain for the production of L-DOPA from glucose. We first used the singleplex genome engineering approach to create an L-DOPA-producing strain, E. coli DOPA-1, by deleting transcriptional regulators (tyrosine repressor tyrR and carbon storage regulator A csrA), altering glucose transport from the phosphotransferase system (PTS) to ATP-dependent uptake and the phosphorylation system overexpressing galactose permease gene (galP) and glucokinase gene (glk), knocking out glucose-6-phosphate dehydrogenase gene (zwf) and prephenate dehydratase and its leader peptide genes (pheLA) and integrating the fusion protein chimera of the downstream pathway of chorismate. Then, multiplex automated genome engineering (MAGE) based on 23 targets was used to further improve L-DOPA production. The resulting strain, E. coli DOPA-30N, produced 8.67 g/L of L-DOPA in 60 h in a 5 L fed-batch fermentation. This titer is the highest achieved in metabolically engineered E. coli having PHAH activity from glucose.
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Project description:Backgroundα-Humulene is a plant-derived monocyclic sesquiterpenoid with multiple pharmacological activities, and far-reaching potential for the development of new drugs. Currently, the production of α-humulene is typically achieved via plant extraction, which is not sustainable and limited by low yields. The oleaginous yeast Candida tropicalis has recently emerged as a valuable host for producing high-value-added chemicals. However, the potential of C. tropicalis for terpenoid production has not been exploited.ResultsIn this study, C. tropicalis was engineered for de novo synthesis of α-humulene from glucose. To improve α-humulene production, the codon-optimised α-humulene synthase gene and the entire endogenous farnesyl diphosphate synthesis pathway were co-overexpressed. Furthermore, bottlenecks in the α-humulene synthase pathway were identified and relieved by overexpressing α-humulene synthase, acetoacetyl-CoA thiolase and NADH-dependent HMG-CoA reductase. Combined with fermentation medium optimisation, the engineered strain produced 195.31 mg/L of α-humulene in shake flasks and 4115.42 mg/L in a bioreactor through fed-batch fermentation, a 253- and 5345-fold increase over the initial production, respectively.ConclusionsThis study demonstrates the potential of C. tropicalis for α-humulene production, and presents a platform for the biosynthesis of other terpenoids.
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