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TBiological ImagingNew Dimensions in In Vivo ImagingKeynote Speaker AbstractMulti-Scale Structure and Function in the Nervous SystemDr. Mark EllismanProfessor of Neurosciences and BioengineeringDirector, National Center for Microscopy and Imaging ResearchUniversity of California, San DiegoLa Jolla, CAAuditorium7:30-9:00PMhe activities of the National Center for Microscopy and Imaging Research in San Diego in thedevelopment of novel techniques for 3 dimensional visualization of neuronal structures anddirect identification of their protein constituents in situ will be described. This includes a newtechnique for correlated 4 dimensional light and 3 dimensional electron microscopy. A continuingchallenge to neuroscientists and biomedical researchers in general is the understanding of structureson the scale of 1 nm3 to 10's of µm3, a dimensional range that encompasses macromolecularcomplexes, organelles, and multi-component structures like synapses and the cellular interactionswithin tissues. On the smaller end of this range, structures have traditionally been difficult to studybecause they fall in the resolution gap between technologies, such as X-ray crystallography andelectron microscopy on the lower end, and it is challenging to make correlations between 3D datafrom light and electron microscopy on the upper end. But the continuum of information will have tobe mapped if the results of the molecular revolution, the protein products of sequenced genomes,are to be situated in their proper subcellular, cellular and tissue contexts. The technique of electrontomography, the derivation of 3D structure from a series of 2D electron microscopic images, hasgone a long way towards bridging the resolution gaps. While electron tomography is a useful technique for providing information in this spatial domain, development of new methods to provideselective contrast to molecular constituents, organelle complexes, cells and cell processes arerequired. We recently developed a new molecular-tagging technique to chronicle the development,movement and interactions of proteins as they do their work in living cells. [Gaietta et al., ScienceApril 19, 2002]. This multi-scale molecular tagging technology involves the genetic tagging of aprotein with a small binding area (a tetracystine domain between six to 20 amino-acids long), thatthen interacts with a variety of other compounds. Results with two of these compounds, greenFlAsH and red ReAsH, have been used in sequence to provide the ability to monitor the traffickingof proteins in cells. The red label, ReAsh, can then be used to generate reactive oxygen and drive thedeposition of diamino benzadine for direct EM-level detection of the same protein complex. The useof this new labeling method, other multi-scale staining techniques and new advanced imaginginstruments will be described in the context of work create a Biomedical Informatics ResearchNetwork (BIRN). BIRN is a leading example of a virtual distributed database effort that is federatingmultiscale data about the nervous systems.18