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Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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The base pairing RNA Spot 42 participates in a multi-output feedforward loop to help enact catabolite repression in Escherichia coli

ABSTRACT: Bacteria selectively consume some carbon sources over others through a regulatory mechanism termed catabolite repression. Here, we show that the base pairing RNA Spot 42 plays a broad role in catabolite repression in Escherichia coli by directly repressing genes involved in central and secondary metabolism, redox balancing, and the consumption of diverse non-preferred carbon sources. Many of the genes repressed by Spot 42 are transcriptionally activated by the global regulator CRP. Since CRP represses Spot 42, these regulators participate in a specific regulatory circuit called a multi-output feedforward loop. We found that this loop can reduce leaky expression of target genes in the presence of glucose and can maintain repression of target genes under changing nutrient conditions. Our results suggest that base pairing RNAs in feedforward loops can help shape the steady-state levels and dynamics of gene expression. MG1655 lacIq cells harboring the control vector pBRplac or the Spot 42-inducible vector pSpot42 were grown in LB to an ABS600 of ~0.4 and treated with 1 mM IPTG. After 7 min, total RNA was isolated using the hot phenol extraction procedure.

ORGANISM(S): Escherichia coli str. K-12 substr. MG1655

SUBMITTER: Chase Beisel

PROVIDER: E-GEOD-24875 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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The base pairing RNA Spot 42 participates in a multi-output feedforward loop to help enact catabolite repression in Escherichia coli

Project description:Bacteria selectively consume some carbon sources over others through a regulatory mechanism termed catabolite repression. Here, we show that the base pairing RNA Spot 42 plays a broad role in catabolite repression in Escherichia coli by directly repressing genes involved in central and secondary metabolism, redox balancing, and the consumption of diverse non-preferred carbon sources. Many of the genes repressed by Spot 42 are transcriptionally activated by the global regulator CRP. Since CRP represses Spot 42, these regulators participate in a specific regulatory circuit called a multi-output feedforward loop. We found that this loop can reduce leaky expression of target genes in the presence of glucose and can maintain repression of target genes under changing nutrient conditions. Our results suggest that base pairing RNAs in feedforward loops can help shape the steady-state levels and dynamics of gene expression.

2011-01-01 | GSE24875 | GEO

Escherichia coli str. K-12 substr. MG1655

Project description:The base pairing RNA Spot 42 participates in a multi-output feedforward loop to help enact catabolite repression in Escherichia coli

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Transcriptional effects of CRP* expression in Escherichia coli

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Transcriptional effects of CRP* expression in Escherichia coli

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Expression analysis, A. actinomycetemcomitans wild type (JP2) vs CRP deletion mutant both grown anaerobically.

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Expression profiling of a spf deletion mutant suggests biological roles and mRNA targets for Spot 42 in the fish pathogen Aliivibrio salmonicida

Project description:Spot 42 was discovered in Escherichia coli nearly 40 years ago as an abundant, small and unstable RNA. Its biological role remained obscure until it was shown to cause discoordinate expression of the galactose operon (gal operon). Recently Spot 42 has also been implicated in having broader roles in the central and secondary metabolism. Spot 42 is encoded by the spf gene. The gene is ubiquitous in the Vibrionaceae family of gamma-proteobacteria, which includes a number of serious pathogens of humans and animals, including the infamous Vibrio cholerae. One member of this family, Aliivibrio salmonicida, causes cold-water vibriosis in farmed Atlantic salmon. Its genome encodes Spot 42 with 84 % identity to E. coli Spot 42 (spf). We generated a A. salmonicida spf deletion mutant. We then and used microarray and Northern blot analyses to monitor global effects on the transcriptome in order to provide insights into the biological roles of Spot 42 in this bacterium. In the presence of glucose we found a surprisingly large number of ≥2× differentially expressed genes, and several major cellular processes were affected, such as carbohydrate metabolism and transport, motility and chemotaxis, iron homeostasis and quorum sensing. A gene encoding a pirin-like protein (VSAL_I1200) showed an on/off expression pattern in the presence/absence of Spot 42, which suggests that Spot 42 plays a key regulatory role in the central metabolism by regulating the switch between fermentation and respiration. Interestingly, in a global search we discovered a sRNA, named VSsrna24, which is encoded immediately downstream of spf. This new sRNA has an expression pattern opposite to that of Spot 42, and its expression is highly dependent on glucose. Our hypothesis is that this novel sRNA works in concert with Spot 42 to regulate carbohydrate metabolism and uptake.

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2019-10-07 | PXD014774 | Pride

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