Gene discovery from microbial gene libraries I: protection against reactive oxygen species-driven DNA damage.

Reactive oxygen species (ROS) pose a lethal risk for all life forms by causing damage to cell processes, genome-wide DNA damage-driving mutation, replicative instability, and death. Thus, the development of mechanisms to resist or repair ROS-induced DNA damage is critical for the reliable replication of nucleic acids. DNA repair and protection mechanisms have been discovered in all forms of life. However, the vast array of microbes that may harbor novel repair or protection mechanisms, especially bacterial viruses, have not been adequately assessed. Here, we screened a microbial gene library composed primarily of phage open reading frames (ORFs) to uncover elements that overcome a DNA damage blockade. We report the discovery of one such protein, termed F21, which promotes bacterial survival by possibly repairing or protecting DNA in the face of ROS-induced DNA damage.IMPORTANCEDiscovery of proteins that promote DNA damage repair and protection in the face of reactive oxygen species (ROS) is of vital importance. Our group is in possession of a unique microbial DNA library with which we can screen for undiscovered genes that encode novel proteins with DNA damage repair and protective functions. This library is composed of diverse DNA from a variety of sources, namely bacteriophages, which must be assessed for their novel functions. This work focuses on the discovery of DNA damage repair and protection, but the possibilities for discovery are endless, thus highlighting the significance of this work.