Description: The UCLA Transgenic Mouse/Embryonic Stem (ES) Cell Shared Resource was established to accommodate individual investigator?s needs in the production of transgenic and knockout mice and to provide for rederivation of strains to create specific pathogen-free mice. Resource personnel serve as consultants to many different investigations providing information on specific transgenic animal models, the design and assembly of DNA constructs, and the development of new methods. Materials can also be provided to investigators who wish to perform projects in their own laboratories. There are two separate components of the resource: Transgenic Mouse and ES Cell Culture. The Transgenic Mouse Facility was established in 1991. Although not funded by NCI in the last competitive renewal application, the institution has subsidized the facility?s operation because access to transgenic and knockout technology plays a vital role in the Cancer Center?s research mission. The facility performs pronuclear injections of DNA and blastocyst injections of targeted ES cells, rederives mouse strains, and maintains transgenic animal lines in their initial stages. The Embryonic Stem Cell Facility is not yet operational. Institutional funds have been utilized to recruit a director, renovate space, and provide equipment for the facility. Once operational, a formal service for culture, electroporation, drug selection, and expansion of ES clones will be available. The measure of usage is based on injection days for the transgenic facility and targeting projects for the ES facility. The total capacity for the transgenic facility is 240 injection days and for the ES facility, 25 cell targeting projects. Twenty four UCLA faculty members used the resource representing assistance to 66 individual projects. Of these, use by peerreviewed Cancer Center members totaled 60 percent. The total operating budget of the shared resource for 1997-1998 is $259,672, with 25 percent requested, 50 percent to be obtained from AIDS chargebacks, and 25 percent from institutional support.