CUL1 and infection: Lysates of 293T cells that were transfected with HA-FBXW11 and myc-CUL1 expression plasmids were combined with the lysates of HeLa cells infected with wildtype rMP-12 or rMP-12 mutant viruses expressing NSs -R173A, -D259A, -GE, or -DGE mutants that were either mock treated or treated with doxycycline for 48h prior to start of infection.