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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. |
- Holmqvist, Erik, 1977-, et al.
(författare)
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RNA-binding activity and regulatory functions of the emerging sRNA-binding protein ProQ
- 2020
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Ingår i: Biochimica et Biophysica Acta. Gene Regulatory Mechanisms. - : Elsevier BV. - 1874-9399 .- 1876-4320. ; 1863:9
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Forskningsöversikt (refereegranskat)abstract
- Regulatory small RNAs (sRNAs) ubiquitously impact bacterial physiology through antisense-mediated control of mRNA translation and stability. In Gram negative bacteria, sRNAs often associate with RNA-binding proteins (RBPs), both to gain cellular stability and to enable regulatory efficiency. The Hfq and CsrA proteins were for long the only known global RBPs implicated in sRNA biology. During the last five years, the FinO domain-containing protein ProQ has emerged as another global RBP with a broad spectrum of sRNA and mRNA ligands. This review provides a summary of the current knowledge of enterobacterial ProQ, with a special focus on RNA binding activity, RNA ligand preferences, influence on RNA stability and gene expression, and impact on bacterial physiology. Considering that characterization of ProQ is still in its infancy, we highlight aspects that, when addressed, will provide important clues to the physiological functions and regulatory mechanisms of this globally acting RBP.
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| 3. |
- Pan, Gang, et al.
(författare)
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Polymorphisms rs55710213 and rs56334587 regulate SCD1 expression by modulating HNF4A binding
- 2021
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Ingår i: Biochimica et Biophysica Acta. Gene Regulatory Mechanisms. - : Elsevier. - 1874-9399 .- 1876-4320. ; 1864:8
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Tidskriftsartikel (refereegranskat)abstract
- The stearoyl-CoA desaturase 1 (SCD1) gene at 10q24.31 encodes the rate limiting enzyme SCD1 that catalyzes the biosynthesis of monounsaturated fatty acids (MUFAs) from saturated fatty acids (SFAs). Dysregulated SCD1 activity has been observed in many human diseases including non-alcoholic fatty liver disease (NAFLD), obesity, hypertension, hyperlipidemia, metabolic syndrome and several types of cancer. HNF4A is a central regulator of glucose and lipid metabolism and previous studies suggested that it is deeply involved in regulating the SCD1 activity in the liver. However, the underlying mechanisms on whether and how SCD1 is regulated by HNF4A have not been explored in detail. In this study, we found that HNF4A regulates SCD1 expression by directly binding to the key regulatory regions in the SCD1 locus. Knocking down of HNF4A significantly downregulated the expression of SCD1. Variants rs55710213 and rs56334587 in intron 5 of SCD1 directly reside in a canonical HNF4A binding site. The GG haplotype of rs55710213 and rs56334587 is associated with decreased SCD1 activity by disrupting the binding of HNF4A, which further decreased the enhancer activity and SCD1 expression. In conclusion, our study demonstrated that SCD1 is directly regulated by HNF4A, which may be helpful in the understanding of the altered metabolic pathways in many diseases associated with dysregulated SCD1 or HNF4A or both.
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