EDDS, an Escherichia coli-based system with a variety applications amenable to miniaturization

Abstract

The miniaturization of molecular biology technologies into formats reminiscent of electronic 'chips' has proceeded rapidly, with nucleic acids allowing high-throughput DNA and RNA analysis. This has ushered in new eras in both biology and commerce with potentials yet to be fully appreciated and realized. Similar developments will be possible in other biological areas, as appropriate tools are adapted to formats amenable to miniaturization. Microchips with fluid-handling capabilities will allow for the growth of organisms in micro-formats. Whole-cell-based approaches will permit complex biological endpoints to be assayed. Escherichia coli provides a robust platform for a variety of assays that cover a diverse collection of biological endpoints, and we have developed a number of E. coli-based assays. Our most advanced platform is EDDS (E. coli dimer detection system). EDDS is a protein-protein interaction system (in some ways analogous to the yeast two-hybrid system) that is uniquely able to address membrane protein interactions. This presentation describes the principles behind EDDS and several of its implementations. We have developed applications of EDDS that include small molecule drug discovery, receptor-ligand interactions and matching, and proteomic applications that generate reagents useful in the description of gene function. EDDS and other microbial models that express mammalian genes provide surrogate systems for the development of many assays with diverse biological endpoints. Microbes are more robust and economical than mammalian cells and with their simple growth requirements will be amenable to the development of chip-based assays. A nanoliter of culture media can contain over 103 bacterium that can be engineered to provide signals that could be based on a wide range of complex biological endpoints.