There has been a rapid growth in the use of digital imaging at Vanderbilt over the last three years. Some of this due to newly faculty, but much of it has arisen from success of the Cell Imaging Shared Resource in teaching researchers to use the confocal microscopy cannot be met by the one instrument that is currently available to Vanderbilt faculty. In an effort to remedy this deficit, several well established users of the existing confocal microscope began discussion a plan for sharing the use and maintenance costs of a new instrument. The Major Users included in this proposal compromise a core group share related research goals and employ similar techniques. For example, both Denison and Solnica-Krezel are performing time-lapse imaging experiments on live cells and embryos and at least two other investigators (Hogan, Wright) anticipate using this approach. The PI, Miller, in collaboration with Dave Piston, the Director of the Cell Imaging Resource, have developed methods for multicolor-GFP imaging in the LSM510. Denison, Solnica-Kerezel and Miller intend to exploit GFP multiplexing in their projects. Severak of the Major Users will employ multicolor labeling in fixed tissues with immunochemical or cytological dyes (Denison, Hogan, Wright, Solnica-Kerezel). The computer controlled, multiple laser lines of the LSM510 (458, 488, 514, 633) provide the full range of excitation wavelengths and powers needed by these investigators. Although the microscope will be largely utilized by the Major Users, microscope time will be allocated through the Cell Imaging Shared Resource to insure that allotments are fair and that unscheduled time can be used by other investigators at Vanderbilt.