Abstract

The yeast two‐hybrid system is a genetic method that detects protein‐protein interactions. One application is the detection by library screening of new interactors of a protein of known function. In the August issue of Nature Genetics, Fromont‐Racine et al.1 showed for the first time that the construction of the protein interaction map of a complex pathway, such as that of the mRNA splicing machinery, is now possible, because of the combination of recent technical improvements elaborated in several laboratories. With a yeast cell mating procedure that increases screen efficiency, they used their complex yeast genomic library of 5 × 106 clones to test 700 × 106 interactions against 15 proteins. They identified and classified 170 potential interactors, including approximately 70 proteins of previously unknown function. More than 25% of the interactors are probably biologically relevant. The achievements of Fromont‐Racine et al. have opened the way to the systematic analysis of the protein interaction networks of the 6,000 open reading frames‐yeast proteome. This task requires, however, automation of the library screens and creation of a two‐hybrid library database. BioEssays 20:1–5, 1998. © 1998 John Wiley & Sons, Inc.