Project Summary Peroxisomes are metabolic organelles that serve as a central hub of cell signaling pathways and have essential roles in the normal development and functions of all human organ systems. Peroxisome dysfunction is causally responsible for a large group of rare monogenic disorders where some individuals with the same deleterious alleles can show dramatic differences in clinical phenotypes that suggest the existence of genetic modifiers. Furthermore, peroxisome dysfunction contributes to the pathophysiology of a diverse group of common disorders. Despite their relevance to numerous facets of human health and disease, the limited number of well- annotated publicly available mouse models and immunological resources required to investigate peroxisome structure, assembly, and downstream functions has hindered the research community. Moreover, the impact of many existing mouse models has been lessened since they often are placed on suboptimal genetic backgrounds or are not readily available to the public because the investigators who generated them do not have the infrastructure necessary to distribute them or are encumbered with restrictions or licensing fees to for-profit companies by the originating research institutions. Here, we will establish the Mouse Peroxisome Research Resource (MPRR) at The Jackson Laboratory (JAX) that will provide a central resource for mouse models and monoclonal antibodies for basic and translational research relevant to peroxisome biology and disorders caused by peroxisome dysfunction. The MPRR will be a community-driven effort that leverages a world-leading knowledge of mouse genetics, gene editing, and monoclonal antibody production capability as well as expertise in model development and disease model repositories to accelerate the creation, distribution, and proper use of high-impact mouse models and monoclonal antibody reagents. By leveraging the JAX Genetic Resource Sciences Repository infrastructure, the MPRR will ensure that all deposited mouse models are on standardized genetic backgrounds to control for the presence of genetic modifiers. These strains will be made available as well-annotated resources with as few legal restrictions as possible. Based on community input and the guidance of its External Steering Committee, the MPRR will also produce novel high-priority mouse models with defined genotypes on standardized genetic backgrounds, cryopreserve them, and distribute them to the public. Moreover, the MPRR will also assist in the targeted phenotyping of these models, including measurement of relevant peroxisomal metabolite levels. Furthermore, based on community input and the guidance of the External Steering Committee, the MPRR will produce and publicize validated monoclonal antibody reagents for peroxisome research, including characterizing relevant mouse models, that are made available to the public upon request. Overall, the MPRR will dramatically increase the number of available mouse model...