Translational coupling via termination-reinitiation in archaea and bacteria

Area of Science:

• Genomics
• Molecular Biology
• Microbiology

Background:

• Prokaryotic genomes frequently feature gene pairs with overlapping stop and start codons.
• Translational coupling is a potential functional advantage of these overlapping gene arrangements.

Purpose of the Study:

• To investigate the prevalence and mechanisms of translational coupling in overlapping gene pairs across diverse prokaryotes.
• To experimentally validate translational coupling in selected archaeal and bacterial gene pairs.

Main Methods:

• Bioinformatic analysis of 720 archaeal and bacterial genomes to identify overlapping gene pairs.
• Experimental validation using mutational analysis of Shine-Dalgarno (SD) motifs in Haloferax volcanii and Escherichia coli.

Main Results:

• A significant, though variable, proportion of co-directed overlapping gene pairs were identified across major prokaryotic phyla.
• Experimental testing confirmed strict translational coupling in 13 out of 14 examined gene pairs.
• The contribution of SD motifs to translational coupling varied significantly between different gene pairs.

Conclusions:

• Overlapping gene pairs with tight translational coupling are widespread in archaea and bacteria.
• The utilization of SD motifs for regulating coupled translation is diverse.
• This widespread mechanism suggests an important role in prokaryotic gene expression regulation.