Figure 6. Multiple signaling pathways are coordinately involved in the ER stress response in C. glabrata.
(A) The C. glabrata Δire1, Δcnb1, Δcrz1, and Δslt2 deletion mutants were transformed with either an empty vector or a plasmid containing the corresponding wild-type gene. Logarithmic-phase cells were adjusted to 2×107 cells/ml, and then 5 µl of serial 10-fold dilutions were spotted onto synthetic complete medium without tryptophan (SC-trp) plates in the presence and absence of tunicamycin (TM) and dithiothreitol (DTT) at the indicated concentrations. Plates were incubated at 30°C for 48 h. (B) Time-kill analysis of the C. glabrata deletion mutants in the presence of TM. Logarithmic-phase cells (5×105 CFU/ml) were incubated in SC medium containing 1.5 µg/ml TM. The number of viable cells was determined by plating the appropriate dilutions on YPD plates at the indicated time points. Data are expressed as the percentages of viability relative to the untreated (time point 0) control in each strain. The means and standard deviations for three independent experiments are shown. C. glabrata strains: Wild-type, CBS138; Vector control, TG11; Δire1, TG122; Δire1+IRE1, TG123; Δcnb1, TG162; Δcnb1+CNB1, TG163; Δcrz1, TG172; Δcrz1+CRZ1, TG173; Δslt2, TG152; Δslt2+SLT2, TG153; Δcnb1 Δire1, TG1612; Δcrz1 Δire1, TG1712; and Δslt2 Δire1, TG1512.