A small RNA activates CFA synthase by isoform-specific mRNA stabilization

Area of Science:

• Microbiology
• Molecular Biology
• RNA Biology

Background:

• Small RNAs (sRNAs) primarily repress gene expression through mRNA degradation or translational inhibition.
• Mechanisms by which sRNAs activate gene expression at the mRNA level are less understood.
• The predominant activation mechanism involves translational control by preventing inhibitory mRNA structures.

Purpose of the Study:

• To elucidate the mechanism of gene activation by small RNAs.
• To investigate the role of the small RNA RydC in regulating cfa mRNA isoforms in Salmonella enterica.
• To identify novel sRNA-mediated gene activation pathways.

Main Methods:

• Investigated the interaction between RydC and cfa mRNA.
• Analyzed the effect of RydC on cfa mRNA stability and translation.
• Utilized genetic and biochemical approaches in Salmonella enterica.

Main Results:

• Discovered a translation-independent activation mechanism for cfa mRNA by RydC.
• RydC activates the longer cfa mRNA isoform through seed pairing at the 5' untranslated region.
• This interaction stabilizes cfa mRNA by interfering with RNase E-mediated decay.
• The activation mechanism is generic and can be achieved by unrelated small RNAs.

Conclusions:

• RydC employs a novel mechanism to activate gene expression by stabilizing mRNA.
• This pathway is independent of translational control and relies on direct interaction with the target mRNA.
• The findings suggest potential applications in designing synthetic RNA-based regulatory circuits.
• RydC is the first sRNA identified to regulate bacterial membrane stability.