A–B) Induction of RPN4 transcription, as determined by RT-PCR, after treatment with sodium arsenite (1 mM) or patulin (50 μg/mL) for one hour. ACT1 serves as a control.
C) Rpn4 protein levels after treatment with patulin (30 μg/mL) in the absence or presence of the transcriptional inhibitors actinomycin D (20 μg/mL) or α-amanitin (20 μg/mL). Whole cell extracts from a wild-type strain were prepared and analyzed by SDS-PAGE followed by immunoblot with anti-Rpn4 antibody (upper panel) or anti-Pgk1 antibody (lower panel; loading control).