others have functions in protein sellekchem turnover, organization of the cytoskeleton and DNA repair. To further examine the link between Tra1 and cellular stress response we tested the sensitivity of the tra1SRR3413 strain to rapamy cin and to staurosporine. As shown in Figure 4, the tra1SRR3413 strain was partially sensitive to rapamycin, and to a lesser extent staurosporine. As staurosporine results in cell wall instability through its action on Protein Kinase C, we also examined the tra1SRR3413 strain for sensi tivity to the combination Inhibitors,Modulators,Libraries of calcofluor white and stau rosporine. The tra1SRR3413 Inhibitors,Modulators,Libraries strain was extremely sensitive to calcofluor white in the presence of staurosporine, consist ent with a role for Tra1 in events required for cell wall integrity.

Relationship of tra1SRR3413 to other mutations in SAGA SLIK and NuA4 components Bruno et al. have shown that deletion of the Ada2 homologue in C. albicans results in sensitivity to cell wall destabilizing agents. In addition, both SAGA SLIK and NuA4 have been suggested to be involved in stress response based upon the transcription profiles of deletion strains. Inhibitors,Modulators,Libraries As some of the genetic interactions and phenotypes of the tra1SRR3413 strain may result from a SAGA SLIK or NuA4 dependent inability to induce stress response genes, we analyzed staurosporine, calcofluor white, calcofluor white plus staurosporine and rapamycin sensitivity in strains deleted for additional components of these complexes. The effect of tra1SRR3413 under each of these conditions is similar to, though slightly less severe than, that seen upon deletion of the ada genes of the SAGA SLIK com plexes.

Interestingly, despite the fact that deletion of spt7 results in disruption of the complexes, spt7 0 results in less of an effect on rapamycin and calcofluor white than dele tion of the ada genes, suggesting a potential role for an independent Ada complex. This similarity between the ada genes and tra1SRR3413 is also consistent with our previous Inhibitors,Modulators,Libraries finding that the expression profile in the tra1SRR3413 strain most closely resembled deletion of ada2. Less similarity was seen in the phenotypes with NuA4 components though deletion of yaf9 and eaf7 did lead to reduced growth in calcofluor white plus staurosporine containing media and deletion of yaf9 resulted in a slight reduction of growth in media containing rapamycin.

GFP tagged Tra1 localizes to nucleus The requirement for an intact C terminal FATC domain has meant that Tra1 localization has not been tested in genome wide screens. Localization of Tra1 Inhibitors,Modulators,Libraries to sites outside the nucleus potentially could account for the broad range of genetic interactions seen for the molecule. To examine U0126 order cellular localization, we engineered an N terminally GFP tagged allele of TRA1 that is functional as determined by plasmid shuffling assays.