SOS-independent bacterial DNA damage responses: diverse mechanisms, unifying function

Cells across domains of life have dedicated pathways to sense and respond to DNA damage. These responses are broadly termed as DNA damage responses (DDRs). In bacteria, the best studied DDR is the Save our Soul (SOS) response. More recently, several SOS-independent DDRs have also been discovered. Studies further report diversity in the types of repair proteins present across bacterial species as well as differences in their mechanisms of action. Although the primary function of DDRs is preservation of genome integrity, the diverse organization, conservation, and function of bacterial DDRs raises important questions about how genome error correction mechanisms could influence or be influenced by the genomes that encode them. In this review, we discuss recent insights on three SOS-independent bacterial DDRs. We consider open questions in our understanding of how diversity in response and repair mechanisms is generated, and how action of these pathways is regulated in cells to ensure maintenance of genome integrity.

Automated summary

Cells have specialized pathways to sense and respond to DNA damage, with bacteria having the well-studied SOS response and other SOS-independent DNA damage responses. The diversity in response and repair mechanisms raises important questions about their influence on genomes and vice versa. This review discusses recent insights on three SOS-independent bacterial DNA damage responses, exploring the mysteries of their diversity generation and regulation in cells for genome integrity maintenance.