Many interactions between components involved in cell-cell signaling are highly dynamic, making them difficult to study by standard biochemical techniques. To circumvent this problem, in collaboration with Stephen Miller (UMass Medical Center) we develop novel site-specific crosslinkers to assay dynamic protein-protein interactions in vivo. We are also interested in high-resolution imaging of chromosomes, using a novel chemical method we developed to label DNA in cells. This method is faster, more sensitive and less disruptive than currently available methods, allowing for superior ultrastructural investigations.