Project Summary Abstract We request an administrative supplement to grant R35GM149355 for the purchase of an Isothermic Cryogenic Dry-Vapor Freezer from Custom Biogenic Systems. This is to replace our current Isothermic Cryogenic Dry- Vapor Freezer which has broken down and is not repairable. The parent grant, R35GM149355, is focused on mechanisms of telomere cohesion in human cells. The goal of our research is to elucidate the proteins and mechanisms required for establishment and resolution of sister chromatid cohesion at human telomeres. As described in the parent grant, the research requires that we generate and store many cell lines. We utilize a broad range of human cell lines, including primary normal human cell lines and cancer cell lines. We store multiple aliquots of these cell lines in a cryogenic freezer. For each of these cell lines we use lentivirus to generate cell lines overexpressing and depleted for the proteins that we proposed to investigate in the grant. We store multiple aliquots of these cell lines in a cryogenic freezer. We then use these cell lines to measure telomere function during long term cell growth and aging. Thus, the research in the grant requires that we freeze and store many cell lines. For this, we require a large, reliable cryogenic storage system. This is essential for the conduct of the research and for the reproducibility of the studies. Our current system has broken down and it is essential that we replace it in order to continue the studies proposed in the grant. This request for equipment is completely within the scope of the parent award.