GSE75557
Overexpression of SSZ1 suppresses temperature sensitivity phenotype of yeasts indicating its novel function to maintain cellular robustness
Ssz1p plays multifunctional roles in diverse cellular activities including forming a ribosome-associated complex to assist new protein synthesis and activating pleiotropic drug resistance (PDR) pathway. Here we report a novel function of SSZ1 to maintain cellular robustness when it is overexpressed. We found overexpression of SSZ1 can suppress the death phenotype of the double mutant ?ire1?scj1 and the temperature sensitivity (TS) phenotype of scj1-1?ire1. Microarray analyses showed that overexpression of SSZ1 induced up-regulation of the genes involved in the PDR pathway and the cell wall integrity (CWI) pathway, but not the unfolded protein response (UPR) pathway. However, overexpression of PDR1 and PDR5 cannot significantly suppress the TS phenotype of scj1-1?ire1, and overexpression of SSZ1 cannot up-regulate the gene expression of lacZ under the control of the unfolded protein response element in SSZ1OE?ire1 compared with that in ?ire1. We infer that the suppression is not through the PDR pathway or through the UPR pathway. It may be through regulating downstream genes of the CWI pathway. Moreover, the peptide-binding domain of Ssz1p is necessary for its suppression of TS phenotype of scj1-1?ire1. Overall design: Genes expression from early log phase of three strains, that is,  ?ire1, SSZ1OE?ire1,  and  SSZ1OE?ire1?scj1. RNA was prepared from independent duplicate or triplicate samples.