The role of ubiquitin-like proteins (UBLs) in DNA repair in vertebrates

The ability to faithfully repair DNA damage is a fundamental property of all living organisms. The major aim of my NSERC research program is to uncover how DNA damage is detected, the signaling and factors that determine DNA repair pathway choice between error-prone or error-free mechanisms, and how DNA repair proceeds in vivo within our cells. To date, DNA repair has been studied primarily in cultured cells grown as a single cell layer. While valuable information has been gained, this approach does not fully represent how our cells grow in 3 dimensions, interact with other cells in a tissue, divide and respond to DNA damage inside our bodies. A number of animal model systems, including worms, flies and more recently, zebrafish, have been used to study biological processes in vivo in whole organisms. Zebrafish are an attractive animal model because unlike worms or flies, they are vertebrates and share a high degree of genetic similarity with humans. Furthermore, zebrafish embryos are completely transparent allowing complex biological processes like DNA repair to be observed in cells within the living animal by fluorescence microscopy. We will use cutting-edge genome engineering and molecular genetic techniques to create zebrafish with altered expression of key DNA repair proteins, or that express fluorescent versions of these proteins, allowing DNA repair to be observed for the first time in a living vertebrate in "real time" by fluorescence microscopy. Using these transgenic zebrafish as our model system, we will investigate several members of a class of proteins known as ubiquitin-like modifiers (UBLs) for their role in DNA repair, which remains poorly defined. In complementary studies, we will use biochemical approaches, mass spectrometry and protein-protein interaction assays to assess the role of these UBLs in human cells and to identify novel molecular pathways involving UBLs implicated in the DNA damage response, as well as their conservation in zebrafish. This research will expand our knowledge of the fundamental process of DNA repair and the role of UBLs in the DNA damage response. These studies will be among the first to study DNA repair in a living vertebrate animal, and will create new tools for scientists to study the DNA damage response using zebrafish. We anticipate our findings will be of broad interest to geneticists, molecular biologists, biochemists, and biotechnologists using microscopy to study fundamental biology.