Project Summary Genetically engineered mice are critical tools for uncovering basic biological processes and for modeling human disease. Mouse models are an integral element of this program, enabling each of the projects to test hypotheses and model human normal and disease states. The principal goal of the Experimental Animal Core is to house mice for all projects in the most cost effective and efficient manner in a readily accessible central facility. The animal core will continue to provide genotyping, help plan the number of mice required for experiments with each investigator and correspondingly, generate the appropriate number of mice required to carry out the proposed studies. Each strain of mice will be housed and generated in direct proportion to the need of the investigator, with a breeding algorithm that is supported by customized software. Statistical tools will be used to ensure that the fewest number of mice are used that can provide reportable results. The core will continue to import the relevant strains of mice required of each investigator and will verify both genotype and maintain the appropriate background genetic strain. In addition to activities associated with mouse husbandry, the core will test and provide preparative regimens for hematopoietic cell transfers and for cell and organ harvesting. A central registry will be maintained for all genetically engineered animals and normal control mouse strains that will be housed in the core facility and used by all projects during the course of this proposal.