The Mouse Molecular Genetics Core will support the components of this Program to facilitate the investigation of the developmental, physiological, and pathological roles of the signaling molecules Bit1, DOCK180, Gab1, and SHEP1. The conditional knockout mouse models generated by each laboratory will be tested for extraembryonic tissue function during development. In addition, each will be tested with appropriate transgenic mouse tumor models. Using a newly developed model based on the K18 gene and the Polyoma Middle T antigen (PyMT) oncogene, the roles of the Bit1, DOCK180, Gab1, and SHEP1 genes in the development of mammary tumors, hepatomas, pancreatic tumors, and prostate neoplasms will be evaluated. In addition, this Core facility will provide investigators with trophoblast stem cells, embryonic fibroblasts, and tumor cells for additional experiments. Finally, this Core will assist and train investigators in embryo development and additional genetic manipulations of their respective genes.