Fig. 1

Identification of upstream components of the UPR pathway in K. marxianus. a Identities of Kar2, Ire1 and Hac1 in K. marxianus to their orthologs in S. cerevisiae (Sc). b Sensitivity of W303-1a, FIM-1ΔU, ire1Δ and hac1Δ mutants to ER stress-inducing reagents. Cells were diluted fivefold and dilutions were spotted onto YPD containing different concentrations of DTT or TM. c Induction of KAR2 upon treatment of DTT and TM. Exponentially growing cells were treated with DTT and TM for indicated times. mRNA level of KAR2 relative to 18s rDNA was measured. The value represented mean ± SD (n = 3). d Splicing of HAC1 upon treatment of DTT and TM. Sizes of the product representing unspliced and spliced forms of HAC1 were 443 bp and 117 bp, respectively. Cells were treated as in c. SWC4 was detected as a loading control. e Schematic representation of HAC1 introns in K. marxianus, K. lactis and S. cerevisiae