Fig. 6.

Proposed model for the role of PML in regulating IFN-γ signaling. (A) IFN-γ-induced STAT-1α DNA-binding and transcriptional activities are reduced in the presence of PML. Because IFN-γ induces the colocalization and formation of a PML-STAT-1α complex in the nucleus, we propose that PML may inhibit the binding of STAT-1α to DNA and thus control its activity, leading to a dampening of IFN-γ inducible genes. (B) In the absence of PML, STAT-1α binds to GAS elements, perhaps with higher affinity, and IFN-γ inducible gene expression is heightened.