BPLF1 promotes the selective degradation of nuclear cullins by the proteasome.

<p><b>A</b>. Cullins are selectively degraded during EBV replication. Western blots of cell lysates from induced Akata-Bx1 were probed with the indicated antibodies. One representative experiment out of three is shown. <b>B</b>. The cullins are degraded by the proteasome. Ten µM of the proteasome inhibition MG132 were added to one aliquot of Akata-Bx1 cells 48 h after induction and the cells were culture overnight before western blot analysis with the indicated antibodies. One representative experiment out of three is shown. <b>C</b>. Representative western blots illustrating the changes in expression levels of cytoplasmic and nuclear cullins. Subcellular fractionation was performed at the indicated time after induction and the efficiency of fractionation was confirmed by probing western blots with antibodies to PARP, histone H1 and β-actin. One representative experiment out of three is shown. <b>D</b>. Quantification of the fold change relative to the levels of expression at time 0. The mean ± SE of three experiments are shown. Significant differences between fold changes in the cytoplasmic and nuclear fractions are indicated * = p<0.01, ** = p<0.001.