Fig 2.

Ad5E1 MECs and -PI31 transfectants were treated for 3 days with 60 units/ml rec (m)IFN-γ. (a) Total cell lysates were subjected to Western blot analysis with antisera specific for α2/MC3, β1i/LMP2, β2i/MECL-1, PA28α, and PA28β. (b) Lysates were centrifuged on a glycerol gradient (10–40%), and collected fractions (600 μl) were probed by Western blot analysis with antisera specific for the immunosubunits. Mature and precursor (pr) forms are indicated. Of note, the strong signals obtained for β5i/LMP7 in Ad5E1 MEC fractions are explained by the high affinity of the β5i/LMP7-specific antiserum rather than by protein quantity. (c) MEC-PA28 and -PI31 transfectant cells cultured for 3 days with or without TET in the absence (Upper) or presence (Lower) of IFN-γ were extracted and probed with antisera specific for PA28α and PA28β or β2i/MECL-1 and β5i/LMP7.