Multiple effects of the bacterial DNA-binding protein SarA on the life cycle of <i>Staphylococcus aureus</i> phages

The dynamic gain and loss of temperate phages is crucial for bacteria to adapt to specific niches. In <i>Staphylococcus aureus</i> Sa3int, phages are highly prevalent in human strains but are missing in most animal strains. The mechanisms that balance phage-bacteria coexistence are only partially understood. We demonstrate that the DNA-binding protein SarA is a key regulator of the phage life cycle. SarA protects bacteria from phage induction in response to DNA damage, yet it can also promote phage propagation by altering the phage receptor or interfering with phage replication. SarA likely functions not only as a transcriptional factor, but also as a bacterial chromosome structural component that controls the phage life cycle at different levels.