The type 6 secretion system immunity protein RhsFI has been repurposed for small RNA regulation in pathogenic E. coli

ABSTRACT: RNA-binding proteins (RBPs) play key roles in regulating virulence gene expression in pathogenic, enterohaemorrhagic E. coli (EHEC). Under virulence-inducing conditions total RNA associated protein purification (TRAPP) identified 443 RNA-associated proteins in EHEC included 35 encoded within pathogen-specific regions of the genome. RNA-binding was confirmed for a sub-set that including RhsFI. In vivo RNA targets for RhsFI included regulatory small RNAs (sRNAs) encoded in 3’ UTRs and we find that sRNA stability is affected in a deletion background. The rhsF-rhsFI locus encodes effector and immunity proteins for the type 6 secretion system (T6SS). T6SS expression is repressed in EHEC, but internal transcription initiation within rhsF generates a sub-genic transcript encoding the toxin domain (RhsFint) and downstream RhsFI. Modelling predicted that RhsFint can dimerise with RhsFI. Deletion of rhsFint rhsFI alters the expression of multiple operons in which embedded sRNAs are direct RhsFI targets. Loss of RhsFint-RhsFI dramatically reduced adhesion to bovine cells in vitro, altered cell morphology and increased acid resistance. Our results indicate that the T6SS immunity protein, RhsFI, binds sRNA in vivo and disrupts the sRNA regulatory network in EHEC to promote host colonisation.

INSTRUMENT(S):

ORGANISM(S): Escherichia Coli

TISSUE(S): Cell Culture

SUBMITTER: Christos Spanos  

LAB HEAD: David Tollervey

PROVIDER: PXD063410 | Pride | 2026-02-23

REPOSITORIES: Pride