Project description:The RNA degradosome is a multi-enzyme assembly that plays a central role in the RNA metabolism of Escherichia coli and numerous other bacterial species including pathogens. The core of the assembly is provided by the endoribonuclease RNase E, one of the largest E. coli proteins. The C-terminal half of RNase E is predicted to be predominantly unstructured and is punctuated with conserved short linear motifs that recruit partner proteins, direct RNA interactions, and enable association with the cytoplasmic membrane. We demonstrate that a subassembly of the degradosome - comprising a 248-residue segment of the C-terminal part of RNase E, the DEAD-box helicase RhlB, and the glycolytic enzyme enolase - serves as a flexible recognition centre that can co-recruit small regulatory RNA (sRNA) molecules and the RNA chaperone Hfq into an effector complex. The association of enolase with the degradosome impacts on carbon utilisation pathways under changing metabolic conditions, most likely by facilitating recruitment and the activity of sRNAs. Our results support a model in which the degradosome captures substrates and regulatory RNAs through the recognition core, facilitates pairing to cognate transcripts, and presents the target to the ribonuclease active sites of the greater assembly for cooperative degradation or processing.
Project description:Experimentally mapped transcriptome structure of Escherichia coli BL21(DE3) by hybridizing total RNA (including RNA species <200 nt) to genome-wide high-density tiling arrays (60 mer probes tiled every 10 nt).
Project description:Heat-responsive and time-resolved changes in transcriptome of E. coli BL21(DE3) Experimentally mapped transcriptome structure of Escherichia coli BL21(DE3) by hybridizing total RNA (including RNA species <200 nt) to genome-wide high-density tiling arrays (60 mer probes tiled every 10 nt).
Project description:UV-crosslining of protein-RNA complexes was employed to capture sRNA-mRNA interactions occuring on the RNA degradosome protein, RNase E, in enterohaemorhaggic E. coli. Abstract from associated mansucript: In many organisms small regulatory RNAs (sRNA) play important roles in the regulation of gene expression by base-pairing to specific target mRNAs. In enterohaemorrhagic E. coli (EHEC), sRNAs are encoded by both the “core” genome and in numerous horizontally acquired pathogenicity islands. To identify functionally important sRNA-target RNA interactions we applied crosslinking and sequencing of hybrids (CLASH) to the core degradosome component RNase E in EHEC. RNase E was shown to bind to many classes of RNA, confirming the wide distribution of degradosome targets. These included several hundred sRNA-mRNA duplexes, and the distribution of non-templated oligo(A) tails indicated that the sRNA target RNase E-mediated cleavage at these interaction sites. Functional repression of target mRNAs was confirmed for the core sRNA RyhB, and the pathogenicity-associated sRNA Esr41. In the case of Esr41, three confirmed target mRNAs participate in iron accumulation and the ∆esr41 strain showed increased growth under conditions of iron limitation. We conclude that CLASH can be used to identify functional targets for bacterial sRNAs.
Project description:Bulk RNA-sequencing was performed on E. coli BL21 (DE3) evolved at 25°C in pH 9 terrific broth media buffered with Tris-HCl (pH 9). The evolved E. coli was characterised and compared to the parent strain during protein expression; the strains were actively grown and compared for gene expression at pH 7 and pH 9 in terrific broth media.
