Gene function and expression: Four years of the post-genomic era of yeast

The yeast Saccharomyces cerevisae is a key model organism in which eukaryotic cell architecture and fundamental cellular mechanisms can be successfully investigated. The yeast genome sequence programme has yielded a wealth of information on some 6000 genes, half of which could not be detected by conventional approaches. Remarkably, some 1000 of these novel gene functions have been deciphered in the four years of yeast post-genomic era. Further, novel insights have been gained into gene structure, gene function, protein-protein interactions, and molecular mechanisms of gene expression. This knowledge that has accumulated by the use of genome-wide micro arrays built from the entire set of yeast genes and by other large-scale approaches, is beginning to merge into useful data libraries. Together with the available literature, these will summarize information on yeast functional genomics, such as genome-wide gene knockout, transcript profiling, microarray datasets, results from systematic two-hybrid screens, drug target discovery, and yeast proteomics. Here again, yeast is at the forefront of providing the opportunity to evaluate the impact of genome sequencing on basic molecular and cell biology investigations of this model organism. This review also summarizes aspects of the molecular mechanisms underlying basal transcription by the RNA polymerases in yeast.