Predictive design of sigma factor-specific promoters
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ABSTRACT:
PROVIDER: PRJEB36433 | ENA |
REPOSITORIES: ENA
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Project description:To engineer synthetic gene circuits, molecular building blocks are developed which can modulate gene expression without interference, mutually or with the host’s cell machinery. Promoter libraries of E. coli sigma factor 70 and B. subtilis B-, F- and W-dependent promoters are exploited to construct prediction models, capable of both predicting promoter TIF and orthogonality of the specific promoters. This is achieved by the creation of high-throughput DNA sequencing data from fluorescence-activated cell sorted promoter libraries.
2020-08-01 | E-MTAB-8734 | biostudies-arrayexpress
Project description: Not available
| S-EPMC7670410 | biostudies-literature
Project description:Flexible regulation of gene expression is essential and highly sought for synthetic biology and biotechnology. Designing regulators with specific functions remains a challenge due to the limited understanding of specific regulatory mechanisms. We design and synthesize 23,640 B-cell-specific promoters, following the design-build-test-learn pipeline in synthetic biology. Synthetic promoters exhibit B-cell-specific expression and lead to diverse expression patterns in B-cells. By conducting MPRA testing, we uncovered the factors that influence promoter strength, including core motifs and motif syntax, which shape B-cell-specific promoter strength. Finally, we developed a deep leaning model capable of predicting promoter activity directly from the sequence, and to predict promoter activity for 26,193 variants identified in the global population, indicating that polymorphisms in IgV gene promoters can influence gene expression. Our work helps to decipher the regulatory code in immunoglobulin genes and offers thousands of non-repetitive promoter elements for B-cell engineering.
2023-05-16 | GSE232161 | GEO
Project description:Characterization of S.lividans TK24 secreted proteome changes upon deletion of certain sigma factors.
2019-02-16 | PXD006818 | Pride
Project description:Like other bacterial species, Mycobacterium tuberculosis has multiple sigma (s) factors encoded in its genome. In previously published work, we and others have shown that mutations in some of these transcriptional activators render M. tuberculosis sensitive to various environmental stresses and, in some cases, cause attenuated virulence phenotypes. In this paper, we characterize a M. tuberculosis mutant lacking the ECF s factor sigma-H. This mutant was more sensitive than the wild type to heat shock and to various oxidative stresses, but did not show decreased ability to grow inside macrophages. Using quantitative reverse transcription-PCR and microarray technology, we have started to define the sigma-H regulon and its involvement in the global regulation of the response to heat shock and the thiol-specific oxidizing agent diamide. We identified 48 genes whose expression increased after exposure of M. tuberculosis to diamide; out of these, 39 were not induced in the sigH mutant, showing their direct or indirect dependence on sigma-H. Some of these genes encode proteins whose predicted function is related to thiol metabolism, such as thioredoxin, thioredoxin reductase and enzymes involved in cysteine and molybdopterine biosynthesis. Other genes under sigma-H control encode transcriptional regulators such as sigB, sigE, and sigH itself. Keywords: comparative genome hybridization design and genetic modification design
2007-08-04 | GSE8689 | GEO
Project description:Escherichia coli uses σ factors to quickly control large gene cohorts during stress conditions. While most of its genes respond to a single σ factor, approximately 5% of them have dual σ factor preference. The most common are those responsive to both σ70, which controls housekeeping genes, and σ38, which activates genes during stationary growth and stresses. Using RNA-seq and flow-cytometry measurements, we show that ‘σ70+38 genes’ are nearly as upregulated in stationary growth as ‘σ38 genes’. Moreover, we find a clear quantitative relationship between their promoter sequence and their response strength to changes in σ38 levels. We then propose and validate a sequence dependent model of σ70+38 genes, with dual sensitivity to σ38 and σ70, that is applicable in the exponential and stationary growth phases, as well in the transient period in between. We further propose a general model, applicable to other stresses and σ factor combinations. Given this, promoters controlling σ70+38 genes (and variants) could become important building blocks of synthetic circuits with predictable, sequence-dependent sensitivity to transitions between the exponential and stationary growth phases.
2022-03-22 | GSE188752 | GEO
Project description:Promoters play a central role in controlling gene regulation; however, a small set of promoters is used for most genetic construct design in the yeast Saccharomyces cerevisiae. The ability to generate and utilize models that accurately predict protein expression from promoter sequence may enable rapid generation of novel useful promoters, facilitating synthetic biology efforts in this model organism. We measured the activity of over 675,000 unique sequences in a constitutive promoter library, and over 327,000 sequences in a library of inducible promoters. Training an ensemble of convolutional neural networks jointly on the two datasets enabled very high (R2 > 0.79) predictive accuracies on multiple prediction tasks. We developed model-guided design strategies which yielded large, sequence-diverse sets of novel promoters exhibiting activities similar to current best-in-class sequences. In addition to providing large sets of new promoters, our results show the value of model-guided design as an approach for generating DNA parts.
2019-12-01 | GSE135464 | GEO
Project description:Sigma factors are an important class of bacterial transcription factors that lend specificity to RNA polymerases by binding to distinct promoter elements for genes in their regulons. Here we show that activation of the general stress sigma factor, B, in Bacillus subtilis paradoxically leads to dramatic induction of translation for a subset of its regulon genes. These genes are translationally repressed when transcribed by the housekeeping sigma factor, A, owing to extended RNA secondary structures as determined in vivo using DMS-MaPseq. Transcription fromB-dependent promoters liberates the secondary structures and activates translation, leading to dual induction. Translation efficiencies between B- and A-dependent RNA isoforms can vary by up to 100-fold, which in multiple cases exceeds the magnitude of transcriptional induction. These results highlight the role of long-range RNA folding in modulating translation and demonstrate that a transcription factor can regulate protein synthesis beyond its effects on transcript levels.
2021-03-06 | GSE168393 | GEO
Project description:An alternative sigma factor (σ32) recognizes the unique set of promoters upon heat shock. Here, we determined 54 σ32 promoters at nucleotide resolution using ChIP-exo, enabling us to compare those with housekeeping σ70 promoters. The results elucidated the overarching principles of promoter overlapping between the two σ-factors, which are sequence-specific non-, half-, and full-shared modes with a perfect sequence conservativeness of −35 element as a key determinant of full-shared mode.
2020-08-12 | GSE60668 | GEO
Project description:An alternative sigma factor (σ32) recognizes the unique set of promoters upon heat shock. Here, we determined 54 σ32 promoters at nucleotide resolution using ChIP-exo, enabling us to compare those with housekeeping σ70 promoters. The results elucidated the overarching principles of promoter overlapping between the two σ-factors, which are sequence-specific non-, half-, and full-shared modes with a perfect sequence conservativeness of −35 element as a key determinant of full-shared mode.
2020-08-12 | GSE60667 | GEO