Secondary Structure across the Bacterial Transcriptome Reveals Versatile Roles in mRNA Regulation and Function

Area of Science:

• Bacterial molecular biology
• RNA structure and function
• Gene expression regulation

Background:

• Messenger RNA (mRNA) is primarily known as the intermediary between DNA and protein synthesis.
• Emerging research suggests mRNA plays roles in broader cellular processes.
• The global impact of mRNA secondary structures on bacterial gene expression, translation, and stability remains largely unexplored.

Purpose of the Study:

• To investigate the global role of mRNA secondary structures in bacterial gene expression.
• To correlate mRNA structural features with translation efficiency and transcript abundance in E. coli.
• To elucidate the functional implications of mRNA secondary structures in translation and degradation pathways.

Main Methods:

• Utilized three high-resolution sequencing techniques to map mRNA secondary structures.
• Analyzed global mRNA secondary structures in conjunction with translation efficiency and abundance data.
• Integrated structural data with known regulatory elements and degradation pathways in E. coli.

Main Results:

• Identified poorly structured regions upstream of coding sequences that bind ribosomes, negatively correlating with gene expression.
• Found that secondary structures within coding sequences are dynamic and have limited impact on translation efficiency.
• Observed secondary structures upstream of stop codons are enriched in UAA-terminated genes, suggesting a role in translation termination.
• Uncovered a common recognition signature for RNase E-mediated mRNA cleavage.

Conclusions:

• The study defines the E. coli RNA structurome, revealing mRNA secondary structures as direct effectors of cellular processes.
• mRNA secondary structures significantly influence translation efficiency, mRNA degradation, and translation termination.
• These findings provide a comprehensive understanding of mRNA structure's role in bacterial gene regulation.