FIG. 3.

CPAFcp is necessary for degradation of the host transcription factor RFX5. (A) CEs of HeLa cells alone (HeLa-CE) or HeLa cells infected with C. pneumoniae AR39 strain (AR39-CE) or infected with C. trachomatis LGV2 strain (L2-CE) were used as the sources of enzymes for degrading RFX5 in HeLa cell NE in a cell-free degradation assay as described in the Fig. 1 legend. Equivalent amounts of CEs were used for each reaction. RFX5 was detected with a rabbit anti-RFX5 antiserum. Note that both AR39 and L2 CEs degraded RFX5, but HeLa-CE failed to do so. (B) AR39-CE was absorbed with an anti-CPAFcp or control antibody as described in Materials and Methods, and both the intact AR39-CE and the final remaining supernatants after antibody absorption were measured for their ability to degrade RFX5 in a HeLa cell NE by using the cell-free degradation assay. Note that AR39-CE depleted with the anti-CPAFcp antibody lost most of its RFX5 degradation activity, whereas the AR39-CE depleted with the control antibody maintained the same level of degradation activity as the intact AR39-CE.