EXPRESSION GENE TRAP MUTAGENESIS DEFINES DEVELOPMENTALLY REQUIRED GENES
William L Stanford
Samuel Lunenfeld Research Institute
600 University Ave, Rm. 989A
Toronto, Ontario M5G 1X5 Canada
Co-Authors: Bernstein A, Cohn JB
Institutions: Samuel Lunenfeld Research Institute
We are performing gene trap-based expression and genotypic screens to generate new mouse mutations that will help delineate the molecular controls of specific developmental programs. Using a polyA trap vector with recombination sites for post-insertional manipulations, gene trap insertions are screened using multiplexed in vitro differentiation and induction assays. An expression profile is being generated at a rate of greater than 5000 per year. Sequence tags for all insertions demonstrating restricted expression patterns (about 20%) are now being generated. A database is being developed that will be searchable by expression pattern, sequence, and phenotype. The clones will be available as a resource to researchers worldwide. One of the clones identified in our ongoing screen, SNAG-1, is expressed by hematopoietic stem cells, neural endothelial cells, cardiomyocytes and sensory nerves. SNAG-1 mutant embryos die mid-gestation with neural vascular hemorrhaging and cardiac edema. SNAG-1 encodes a protein containing an N-terminal SH3 and a C-terminal PX domain. Insertion of the vector into the SNAG-1 locus resulted in a fusion transcript of the upstream SH3 domain and the lacZ reporter, deleting the PX domain. SNAG-1 is differentially regulated upon cellular activation and is localized to the Golgi Apparatus. The vector insertion leads to mis-localization of SNAG-1, suggesting that the PX domain is required for localization and function within the Golgi.