FIG. 3.
CPAF dimers are responsible for degradation of host transcription factors. (A) Cell lysates obtained from cultures infected with C. trachomatis serovar L2 and radiolabeled for 1 h were subjected to a first round of precipitation (Io precipitation) with either MAb 54b or MAb 73. The precipitated pellets were solubilized with an SDS buffer in order to dissociate the CPAFc-CPAFn complexes. The solubilized material was subjected to a second round of precipitation (IIo precipitation) with either the same or heterologous antibodies. Note that the CPAFc-CPAFn dimers were precipitated only during the Io precipitation. (B) Cell-free degradation of RFX5 with the precipitated pellets. For details see the legend to Fig. 2. Note that pellets brought down during Io precipitation but not pellets brought down during IIo precipitation degraded RFX5 regardless of the antibodies used. MW, molecular mass.