Curli synthesis and biofilm formation in enteric bacteria are controlled by a dynamic small RNA module made up of a pseudoknot assisted by an RNA chaperone.Reportar como inadecuado




Curli synthesis and biofilm formation in enteric bacteria are controlled by a dynamic small RNA module made up of a pseudoknot assisted by an RNA chaperone. - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

* Corresponding author 1 Fonction, structure et inactivation d-ARN bactériens

Abstract : RydC pseudoknot aided by Hfq is a dynamic regulatory module. We report that RydC reduces expression of curli-specific gene D transcription factor required for adhesion and biofilm production in enterobacteria. During curli formation, csgD messenger RNA mRNA synthesis increases when endogenous levels of RydC are lacking. In Escherichia coli and Salmonella enterica, stimulation of RydC expression also reduces biofilm formation by impairing curli synthesis. Inducing RydC early on in growth lowers CsgA -B and -D protein and mRNA levels. RydC-s 5-domain interacts with csgD mRNA translation initiation signals to prevent initiation. Translation inhibition occurs by an antisense mechanism, blocking the translation initiation signals through pairing, and that mechanism is facilitated by Hfq. Although Hfq represses csgD mRNA translation without a small RNA sRNA, it forms a ternary complex with RydC and facilitates pseudoknot unfolding to interact with the csgD mRNA translation initiation signals. RydC action implies Hfq-assisted unfolding and mRNA rearrangements, but once the pseudoknot is disrupted, Hfq is unnecessary for regulation. RydC is the sixth sRNA that negatively controls CsgD synthesis. Hfq induces structural changes in the mRNA domains targeted by these six sRNAs. What we describe is an ingenious process whereby pseudoknot opening is orchestrated by a chaperone to allow RNA control of gene expression.





Autor: Valérie Bordeau - Brice Felden -

Fuente: https://hal.archives-ouvertes.fr/



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