RT Journal Article SR Electronic T1 Multiple Holins Contribute to Extracellular DNA Release in Pseudomonas aeruginosa Biofilms JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.10.28.358747 DO 10.1101/2020.10.28.358747 A1 Amelia L. Hynen A1 James J. Lazenby A1 George M. Savva A1 Laura C. McCaughey A1 Lynne Turnbull A1 Laura M. Nolan A1 Cynthia B. Whitchurch YR 2020 UL http://biorxiv.org/content/early/2020/10/28/2020.10.28.358747.abstract AB Bacterial biofilms are comprised of aggregates of cells encased within a matrix of extracellular polymeric substances (EPS). One key EPS component is extracellular DNA (eDNA), which acts as a ‘glue’, facilitating cell-cell and cell-substratum interactions. We have previously demonstrated that eDNA is produced in Pseudomonas aeruginosa biofilms via explosive cell lysis. This phenomenon involves a subset of the bacterial population explosively lysing, due to peptidoglycan degradation by the endolysin Lys. Here we demonstrate that in P. aeruginosa three holins, AlpB, CidA and Hol, are involved in Lys-mediated eDNA release within both submerged (hydrated) and interstitial (actively expanding) biofilms, albeit to different extents, depending upon the type of biofilm and the stage of biofilm development. We also demonstrate that eDNA release events determine the sites at which cells begin to cluster to initiate microcolony formation during the early stages of submerged biofilm development. Furthermore, our results show that sustained release of eDNA is required for cell cluster consolidation and subsequent microcolony development in submerged biofilms. Overall, this study adds to our understanding of how eDNA release is controlled temporally and spatially within P. aeruginosa biofilms.Competing Interest StatementThe authors have declared no competing interest.