A synthetic cell phage cycle.

Abstract

Viral infection of living cells, exemplified by bacteriophage interaction with bacteria, is fundamental to biology and universal across living systems. Here, we establish an all-cell-free viral cycle where T7 phages infect synthetic cells, equipped with lipopolysaccharides on the outer leaflet of the lipid membrane, while encapsulating a cell-free gene expression system. We track each cycle step to demonstrate T7 phage-specific adsorption onto the liposomes, genome entry, replication, expression, and assembly of new infectious virions within the synthetic cells. We quantify key characteristics of the cycle, including the multiplicity of infection, replication efficiency, liposome size constraints, and phage rebinding dynamics. This work establishes a versatile, fully defined in vitro platform for reconstructing and investigating viral infections from individual molecular components.