ABSTRACT – TRANSGENIC AND TARGETED MUTAGENESIS LABORATORY The Transgenic and Targeted Mutagenesis Laboratory (TTML) is a Northwestern University-wide resource dedicated to the generation, import, recovery/rederivation, and cryopreservation of genetically engineered mice. TTML provides Lurie Cancer Center (LCC) members a broad range of services including generation of transgenic, gene edited, and targeted transgenic mouse models via microinjection; gene targeting/editing of embryonic stem (ES) cells; ES cell microinjection into blastocysts to create germline competent chimera; importation and recovery/rederivation of mouse lines from germplasm; and cryopreservation of mouse sperm and embryos. Since the last review, the core has introduced full-scale, start-to-finish mutagenesis capabilities. These changes were necessary to facilitate the development of newly emerging genome engineering technologies such as CRISPR. The TTML team works with LCC members to design customized genetic modification strategies and genotyping assays, and provides confirmed founders to investigators. These new capabilities, in addition to our traditional methods for creating transgenic and ESC derived mutant lines, enable investigators the opportunity to employ overarching approaches to genetic modification mutagenesis through the facility. The TTML facility is essential for the research programs of investigators of the Lurie Cancer Center who use mouse models to study mechanisms underlying malignancy and validate targets for translational projects. It provides the necessary infrastructure that allows the Center’s investigators access to transgenic technology that normally requires expensive microinjection equipment and skilled staff with expertise in microinjection, microsurgeries, embryo manipulation, animal husbandry, ES cell culture, and genome engineering. In addition, TTML staff provide in-house consultation and recurrent guidance on all transgenic-related technologies including CRISPR-mediated genome editing systems, transgenic and targeting vector design, appropriate screening strategies, DNA purification methods, breeding and analysis of founder mice, appropriate methods for importing mouse lines, and cryopreservation options. Since the inclusion of the TTML as a resource within the Lurie Cancer Center in 1995, Center investigators have consistently been the primary group of NU faculty utilizing the TTML, emphasizing its pivotal role in the overall research mission of the LCC.