Extensive reshaping of bacterial operons by programmed mRNA decay.

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Bacterial operons coordinate gene expression via shared promoters.
• Polycistronic transcripts can exhibit differential RNA decay, affecting gene stability within an operon.
• The extent and evolutionary conservation of mRNA decay-driven regulation remain largely unexplored.

Purpose of the Study:

• To investigate the prevalence and mechanisms of differential mRNA decay in bacterial operons.
• To determine if altered mRNA stoichiometries within operons are shaped by post-transcriptional regulation.
• To assess the evolutionary conservation of RNA structures involved in differential decay.

Main Methods:

• Analysis of mRNA stoichiometries in Escherichia coli (E. coli) operons.
• Investigating post-transcriptional regulation through differential mRNA decay.
• Identifying protective RNA structures within transcripts.
• Examining evolutionary conservation of these RNA structures.
• Assessing the role of ribosome densities in decay processes.

Main Results:

• A significant proportion of E. coli genes within operons exhibit non-uniform mRNA stoichiometries.
• Differential mRNA decay, regulated by protective RNA structures, shapes these operon stoichiometries.
• Protective RNA structures are often located within protein-coding regions and are evolutionarily conserved.
• Ribosome densities and conserved structural RNA elements significantly influence differential decay.

Conclusions:

• Differential mRNA decay plays a substantial role in regulating bacterial gene expression within operons.
• Conserved RNA structures are key determinants of mRNA stability and stoichiometry.
• This post-transcriptional mechanism provides a layer of control over bacterial transcriptomes.