An x-ray irradiator cabinet for live cell irradiation

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The cells of every living organism are constantly being exposed to DNA damage, whether created through by-products of the endogenous metabolism, or generated by extracellular sources such as radiation or chemicals. While DNA damage is commonly encountered, it can cause mutations that have negative impacts on cells, tissues, and organisms as a whole. Failure to repair DNA lesions results in a multitude of conditions including immunodeficiency, aging, cancer, and neurodegenerative disorders. Thus, understanding how cells respond to DNA damage is key to comprehend fundamental mechanisms that are essential to long- and short-term survival of cells and species. The funding provided by this grant will allow the purchase a Faxitron CellRad cabinet X-ray unit that delivers a range of radiation doses for cell and tissue culture irradiation. Cell irradiation causes damage in the genetic material (DNA) of the cells. This serves as an experimental model system to study the mechanisms set in place by mammalian and human cells to repair their damaged DNA. This equipment is essential to carry out the Schild-Poulter lab’s research program funded by NSERC that investigates the role of the DNA repair protein Ku which is essential for the repair of DNA double-stranded breaks in mammalian cells. While it is understood that Ku is essential for the proper repair of DNA, its mode of action is still unclear. It is known that Ku interacts with a number of other factors that play roles in the repair of DNA, however, the details and the outcome of these interactions are poorly understood. Using the crystal structure of Ku, one can predict regions of the protein that are accessible to contact other proteins. Thus, mutations were generated in several of these accessible regions to test how they alter Ku DNA repair functions. Two Ku mutations that alter its ability to function in response to DNA damage have been identified. These mutations result in different defects suggesting that the mutated regions are involved in distinct functions. The Schild-Poulter laboratory is currently working to identify the proteins that interact with these Ku motifs to elucidate how they function together in the repair of DNA. The requested equipment will provide the means to induce DNA damage in our cellular models so that we can elucidate the regulatory mechanisms that underlie Ku function in DNA repair. This equipment is also needed by several other laboratories at Western University for research on stem cell regeneration and cell-mediated immune responses. Thus, the DNA damage created by this equipment is a tool to enable biological systems and experimentations used in biological research by students, scientists and technicians in their individual lab or research program.