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- Baptista, Ines S. C., et al.
(författare)
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Sequence-dependent model of genes with dual s factor preference
- 2022
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Ingår i: Biochimica et Biophysica Acta. Gene Regulatory Mechanisms. - : Elsevier. - 1874-9399 .- 1876-4320. ; 1865:3
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Tidskriftsartikel (refereegranskat)abstract
- Escherichia coli uses sigma factors to quickly control large gene cohorts during stress conditions. While most of its genes respond to a single sigma factor, approximately 5% of them have dual sigma factor preference. The most common are those responsive to both sigma(70), which controls housekeeping genes, and sigma(38), which activates genes during stationary growth and stresses. Using RNA-seq and flow-cytometry measurements, we show that 'sigma(70+38) genes' are nearly as upregulated in stationary growth as 'sigma(38) genes'. Moreover, we find a clear quantitative relationship between their promoter sequence and their response strength to changes in sigma(38) levels. We then propose and validate a sequence dependent model of sigma(70+38) genes, with dual sensitivity to sigma(38) and sigma(70), 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 sigma factor combinations. Given this, promoters controlling sigma 70+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.
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| 2. |
- L. B. Almeida, Bilena, et al.
(författare)
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The transcription factor network of E. coli steers global responses to shifts in RNAP concentration
- 2022
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Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 50:12, s. 6801-6819
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Tidskriftsartikel (refereegranskat)abstract
- The robustness and sensitivity of gene networks to environmental changes is critical for cell survival. How gene networks produce specific, chronologically ordered responses to genome-wide perturbations, while robustly maintaining homeostasis, remains an open question. We analysed if short- and mid-term genome-wide responses to shifts in RNA polymerase (RNAP) concentration are influenced by the known topology and logic of the transcription factor network (TFN) of Escherichia coli. We found that, at the gene cohort level, the magnitude of the single-gene, mid-term transcriptional responses to changes in RNAP concentration can be explained by the absolute difference between the gene's numbers of activating and repressing input transcription factors (TFs). Interestingly, this difference is strongly positively correlated with the number of input TFs of the gene. Meanwhile, short-term responses showed only weak influence from the TFN. Our results suggest that the global topological traits of the TFN of E. coli shape which gene cohorts respond to genome-wide stresses.
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