Figure 5.
A strong N end rule signal targets EBNA1 for proteasomal degradation. (A) HeLa cells transfected with the Ub-M-EBNA1 or Ub-R-EBNA1 plasmids were preincubated for 10 h without (−) or with (+) 10 μM Z-L3-VS and then analyzed in Western blots with a GAr-specific antibody. Bands corresponding in size to the cleaved X-EBNA1 are indicated. The asterisk indicates an additional GAr-containing polypeptide that is mainly detected in Ub-R-EBNA1-expressing cells. Molecular mass markers are indicated on the left. (B) Anticomplement immunofluorescence (Left) and Hoechst (Right) staining of HeLa cells expressing Ub-M-EBNA1 and Ub-R-EBNA1. Magnification: ×200.