Eukaryotic Acquisition of a Bacterial Operon

Area of Science:

• Genomics
• Molecular Biology
• Evolutionary Biology

Background:

• Operons facilitate coordinated gene expression in bacteria but are uncommon in eukaryotes.
• Eukaryotic gene expression typically involves independent transcription of individual genes.

Purpose of the Study:

• To investigate the horizontal transfer of a bacterial operon into eukaryotic yeast.
• To analyze the functional expression and evolutionary modifications of the transferred operon in yeast.

Main Methods:

• Comparative genomics to identify operon transfer.
• Transcriptional analysis to assess gene expression in yeast.
• Evolutionary analysis to track genetic changes post-transfer.

Main Results:

• A bacterial siderophore biosynthesis operon was successfully transferred to budding yeast.
• The operon's genes were expressed with eukaryotic transcriptional features.
• The transferred operon enhanced iron sequestration and uptake in yeast.
• Post-transfer evolution included new transcription start sites, polyadenylation, and gene integration.

Conclusions:

• The operon was acquired as a unit and adapted for eukaryotic expression.
• Selection favored the operon for adaptation to iron-limited conditions.
• This study demonstrates functional horizontal gene transfer and subsequent evolution in eukaryotes.