Defensive hypervariable regions confer superinfection exclusion in microviruses
Paul C. Kirchberger, Zachary A. Martinez, Landry J. Luker, Howard Ochman
Abstract
Significance Numerous studies have demonstrated that single-stranded DNA phages of the family Microviridae can dominate the human virome, yet shockingly little is known about these diminutive viruses. By synthesizing and propagating microviruses in an experimental system, we demonstrate the existence of a widespread mechanism of phage defense by which these viruses antagonize one another. This mechanism functions through the repurposing of an essential viral structural component instead of through the acquisition of accessory genes, a necessity of the size constraints imposed by the minimal microviral genome. This study thus not only sheds much needed light on the biology of the Microviridae but also emphasizes the importance of virus–virus interaction in the evolution of viral genomes.