DNA damage responses and stress resistance: Concepts from bacterial SOS to metazoan immunity

Abstract

The critical need for species preservation has driven the evolution of mechanisms that integrate stress signals from both exogenous and endogenous sources. Past research has been largely focused on cell-autonomous stress responses; however, recently their systemic outcomes within an organism and their implications at the ecological and species levels have emerged. Maintenance of species depends on the high fidelity transmission of the genome over infinite generations; thus, many pathways exist to monitor and restore the integrity of the genome and to coordinate DNA repair with other cellular processes, such as cell division and growth. The specifics of these DNA damage responses (DDRs) vary vastly but some general themes are conserved from ancient organisms, such as bacteria and archaea, to humans. Despite decades of research, however, DDRs still have many layers of complexity and some surprises left to be discovered. One of the most interesting current research topics is the link between DNA damage and stress resistance: the outcomes of DDRs can protect the organism from other secondary challenges. At this time, these types of responses are best characterized in bacteria and the simple metazoan model, Caenorhabditis elegans, but it is becoming clear that similar processes also exist in higher organisms.

Keywords: Caenorhabditis elegans; DNA damage response; Escherichia coli; Immunity; SOS response.

Figure 1. Responses to DNA damage in diverse species share common features to ensure species preservation.

The responses of three organisms to DNA damage are summarized in parallel to demonstrate the universality of the logical framework of how DNA damage responses can promote the preservation of species, despite vast divergence in the molecular mechanisms.