Fig. 8. Proteasome activity is reduced in the hlr mutant. GUS staining of HS::AXR3 NT-GUS, a marker for the degradation of AUX/IAA proteins, in wild type (A,C) and in the hlr-1 mutant (B,D). (A-D) 36-hour-old seedlings stained for 0 (A,B) or 60 minutes (C,D) after the end of heat-shock induction. (E) GUS activity in the absence or presence of the proteasome inhibitor MG132. Relative activity was calculated as a percentage of the number of seedlings with GUS staining in the roots per total number of seedlings examined. Scale bar: 25 µm.