Figure 1. IFNβ stimulates accumulation of immunoproteasome and the 11S mRNAs in a manner preceded by IRF1 gene expression and prevented by IRF1 gene knockout.

Fold increase in the indicated mRNA levels was measured by qPCR (procedure A) in MIN6 cells (A, B) or mice islets (C, D, F, G) exposed to 150 unit/ml of IFNβ or IFNγ. The results represent the mean ± S.E.M. of three (MIN6) or five (islets) experiments. (E) IRF1 protein was visualized by Western blot in whole-cell extracts from MIN6 cells (top) and mouse islets (bottom) treated with IFNβ or IFNγ, as described above; a non-specific (n.s.) protein band serves as a loading control.