1 Department of Molecular Biology, Faculty of Science, Aarhus University, Aarhus University2 Department of Molecular Biology and Genetics - Gene Expression and Gene Medicine, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University3 Department of Molecular Biology and Genetics - Gene Expression and Gene Medicine, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University
Genetic screens can provide novel information about interacting genes and pathways in S. cerevisiae. Conventional approaches are limited, however, because only strong suppressors or enhancers are usually identified. We describe here a novel Microarray-based Enhancer and Suppressor screening (MES) strategy that is capable of identifying a large number of genes that exert more modest effects on the mutant phenotype. MES combines DNA microarray technology with high-copy plasmid expression in liquid media. We conducted MES on a strain deleted for Rrp6p, a nuclear exosome component involved in numerous RNA reactions. These include the processing and degradation of rRNA, snoRNA, snRNA and tRNA as well as surveillance and degradation of aberrant mRNAs. Two bona fide suppressors were found that were not identified using a conventional overexpression/suppression strategy at 37ºC, because they were enhancers at high temperature. They encoded a novel mRNP protein Nab6p and the tRNA transporter Los1p, suggesting that mRNA metabolism or protein synthesis is growth-rate limiting in the ∆rrp6 strain. Conventional microarray assays, which compare the RNA populations of ∆rrp6 strains containing the different suppressors, support this hypothesis.