An intron endonuclease facilitates interference competition between coinfecting viruses

Area of Science:

• Molecular Biology
• Evolutionary Genetics
• Virology

Background:

• Introns encoding homing endonucleases are prevalent genetic elements.
• Their role in host benefit versus selfish propagation remains debated.
• Homing endonucleases are frequently found in viral genomes.

Purpose of the Study:

• To investigate the function of intron-encoded homing endonuclease gp210 from bacteriophage ΦPA3.
• To determine if this endonuclease confers a selective advantage in viral competition.

Main Methods:

• Studied the interaction between bacteriophage ΦPA3 and bacteriophage ΦKZ.
• Analyzed the targeting mechanism of gp210 within the ΦKZ genome.
• Assessed the impact of gp210 on viral progeny assembly.

Main Results:

• Bacteriophage ΦPA3's gp210 endonuclease specifically targets a sequence in the coinfecting bacteriophage ΦKZ.
• This targeting inhibits the replication and assembly of ΦKZ progeny viruses.
• gp210 confers a relative fitness advantage to ΦPA3 during coinfection.

Conclusions:

• Homing endonucleases can function as mediators of interference competition among viruses.
• This mechanism provides a selective advantage, impacting viral evolution.
• The findings suggest widespread evolutionary implications for homing endonucleases in viral and plasmid dynamics.