SMRT-Cappable-seq reveals complex operon variants in bacteria.

Area of Science:

• Microbiology
• Genomics
• Molecular Biology

Background:

• Current genome-wide gene expression analysis methods fragment transcripts, obscuring bacterial operon complexity and accurate 5'/3' end identification.
• In vivo transcript processing further complicates the precise mapping of operon structures in prokaryotes.

Purpose of the Study:

• To develop a novel methodology for analyzing full-length primary transcripts in bacteria.
• To accurately define bacterial operon structures and identify transcriptional variants using long-read sequencing.

Main Methods:

• Developed SMRT-Cappable-seq, combining primary transcript isolation with single-molecule, long-read sequencing.
• Applied the technology to Escherichia coli for comprehensive transcriptome analysis.

Main Results:

• Accurately defined the E. coli transcriptome, extending 34% of known operons by at least one gene.
• Identified read-through transcription at 40% of termination sites, altering operon gene content.
• Revealed that most bacterial genes exist in multiple operon variants, similar to eukaryotic alternative splicing.

Conclusions:

• SMRT-Cappable-seq provides unprecedented granularity in bacterial operon structure.
• This technology is a valuable resource for studying prokaryotic gene networks and regulation.
• The findings challenge the traditional view of static bacterial operons, highlighting dynamic transcriptional units.