Gene autoregulation by 3' UTR-derived bacterial small RNAs

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Negative feedback is a common gene regulation motif, typically involving transcription factors binding to their own promoters.
• Understanding novel regulatory mechanisms is crucial for deciphering complex biological systems.

Purpose of the Study:

• To identify and characterize a novel mechanism of gene autoregulation in bacteria.
• To investigate the role of small regulatory RNAs (sRNAs) and RNase E in negative feedback loops.

Main Methods:

• TIER-seq (transiently-inactivating-an-endoribonuclease-followed-by-RNA-seq) was employed to identify RNase E-dependent cleavage sites in *Vibrio cholerae*.
• Analysis focused on identifying stable sRNAs processed from 3' untranslated regions (3' UTRs).
• The function of specific sRNAs (OppZ and CarZ) in gene regulation was experimentally validated.

Main Results:

• Approximately 25,000 RNase E-dependent cleavage sites were identified in *Vibrio cholerae*.
• Several stable sRNAs, including OppZ and CarZ, were found to accumulate due to these cleavages.
• OppZ and CarZ sRNAs, processed from operon 3' UTRs, inhibit translation of their own transcripts.
• OppZ also triggers Rho-dependent transcription termination, demonstrating dual regulatory control.

Conclusions:

• Bacterial small regulatory RNAs (sRNAs) processed from 3' UTRs represent a novel mechanism for post-transcriptional negative feedback gene regulation.
• This mechanism allows for precise control over gene expression at both the translational and transcriptional levels.
• The findings expand our understanding of gene regulatory networks in bacteria and the multifaceted roles of sRNAs.