Figure 1.

per mutants activate the unfolded protein response pathway. Wild-type and mutant cells carrying the UPRE-LacZ reporter gene are grown logarithmically and lysed. β-galactosidase activity is measured from lysates using 2-nitrophenyl-β-d-galactopyranoside (ONPG) as substrate and detected as an increase in absorbance at 420 nM. TM, cells treated with 2.5 μg/ml tunicamycin for 60 min before lysis.