Yeast (Saccharomyces cerevisiae) Overexpression suppression study

To address the mechanisms of suppression, we analyzed time course of mRNA expression of four suppressed smc2-8 mutant strains. We addressed the question of genomic robustness by systematically screening genomic open reading frames, when induced for high-level expression, for their ability to suppress 55 conditional lethal mutations in yeast, and have discovered 636 suppressor genes participating in 822 novel dosage suppressor interactions.  The suppressor genes are functionally broad and are enriched for overlapping open reading frames where mutually overlapping genes tend to be co-suppressors.  Studies on suppressors of defects in chromosome condensation, telomere stability, and RNA polymerase II function suggest that adding interactions, by making significant connections where only weak or undetectable interactions were present (rewiring of gene regulatory pathways, and interaction within and between protein complexes) are frequent mechanisms of dosage suppression. RNA samples isolated from two individual biological replicates, four time points each (0, 45, 90 and 180 min), of smc2-8 mutant strains harboring pGAL:SMC2, pGAL:UME1, pGAL:MEK1, pGAL:HTA2, pGAL:SNU66, and the negative control MORF plasmid (pGAL:negative, BG1766) and hybridized Affymetrix microarrays.