Phage N4 uses a SAR endolysin-holin system for host cell lysis

Bacteriophages (phages) cause active host cell lysis to terminate their infection and release progeny into the environment. Some phages delay their lysis, and thereby increase progeny yield, in a phenomenon called lysis inhibition (LIN). There are two dissimilar phages of Escherichia coli known to exhibit LIN: T4 and N4. Studies of phage T4 have demonstrated a multi-protein mechanism that stalls lysis and maintains the LIN state in response to superinfection in a high phage population density. However, the lysis proteins responsible for T4 lysis and LIN are not conserved with phage N4. In this study, we characterize the phage N4 proteins involved in lysis by molecular and genetic means. We d