cDNA library screening using the SOS recruitment system

The SOS recruitment system (SRS), a recently developed method for detecting protein-protein interactions, provides an attractive alternative to identify biologically important protein interactions. In SRS, the protein-protein interactions rake place in the cytoplasm instead of the nucleus, as is the case in the conventional two-hybrid system. Athough the SRS has overcome some of the disadvantages of the conventional two-hybrid system, it still has several problems and limitations. Here, we describe a new protocol for SRS library screening. A new combination of growth media to avoid the tedious step of replica plating greatly increases the number of independent colonies irt a single library screening. Furthermore, we designed a pair of ms-specific primers and a one-step simple PCR to rule out the must abundant false positive, the mammalian ras cDNA, in SRS library screening.