CORE 008 – GENOME EDITING SHARED RESOURCE PROJECT SUMMARY/ABSTRACT The mission of the Genome Editing Shared Resource (GESR), previously the Transgenic Mouse/Embryonic Stem Cell Shared Resource, is to enable the Vanderbilt-Ingram Cancer Center (VICC) research community, inclusive of our VICC members and partners at Meharry Medical College, Tennessee State University, and other NCI Cancer Centers to efficiently generate, store and share genetically-altered mouse models. GESR, which has been in existence for over 25 years, has undergone major changes over the past five years. Five prior service lines oriented around gene targeting in mouse embryonic stem cells (mESCs) became unnecessary after the discovery of CRISPR/Cas9. Thus, in late 2015, GESR shifted its focus towards improving the efficiency and outcomes of CRISPR/Cas9-mediated gene editing in one and two cell mouse embryos. Since then, over 800 mutant mice from 97 CRISPR/Cas9 experiments have been generated, with a 100% technical success rate for the past twenty-six projects. GESR now provides a full-service approach where the resource performs project design, pre-injection reagent validation, post-injection analysis of the resulting pups, and breeding of the first generation to provide the investigator with a correctly edited heterozygous mouse. Investigators no longer need extensive molecular biology skills, or even much knowledge about CRISPR/Cas9 gene editing strategies. To support the sharing of these new CRISPR-generated lines, GESR has become more proactive in encouraging the use of core cryopreservation services. In house cryopreservation of mouse lines improves colony management and enables specific pathogen free stocks to be sent as cryopreserved germplasm to other institutions. The resource continues to reconstitute cryopreserved mouse lines that are requested by VICC investigators from other investigators, or that exist within external repositories, by performing both in vitro fertilization and embryo transfer. Finally, the resource has established, and are striving to expand, a Vanderbilt Cryopreserved Mouse Repository (VCMR). The VCMR facilitates compliance with NIH Mouse Sharing Policies and enables storage and distribution of mice from Vanderbilt without the continued involvement of investigators. All microinjection and embryo transfer services are performed in a specific pathogen free barrier facility. Together, the combination of services provided by the GESR enables VICC members and other Vanderbilt investigators to efficiently generate and maintain novel genome-edited mouse models to study multiple aspects of cell and tumor biology using sophisticated mouse models.