Use of a yeast three-hybrid system to clone bridging proteins.

The three-hybrid system described here should facilitate screening cDNA libraries to clone "bridging" proteins in ternary complex. The pDela constructs were initially designed to be compatible with the Gal4-based two-hybrid system, such as pGAD424/pGBT9. The Ura selection offered by pDela makes it easy to introduce the "bridging" protein into the yeast containing the other two hybrids, the BD fusion protein and the AD fusion protein. Because many of the widely used two-hybrid systems employ Trp-, Leu-, His-, or ziocin selection in the shuttle vectors, the Ura(+)-based pDela constructs can be used directly in those systems.