Figure 6.

Zta down-regulates Qp-CAT expression. (A) Qp-CAT was cotransfected into HeLa cells with Zta or Zta variants carrying mutations in the DNA-binding domain (Zdbm1) or the dimerization domain (Zdmmt) or deletions in the activation domain (ZtaΔ2–25, ZtaΔ2–141, ZtaΔ25–86, ZtaΔ93–141). The HHV8-K8 effector and oriLyt-CAT target served as controls for the specificity of the Zta-mediated repression of Qp-CAT. The results shown are an average of two experiments, with the standard deviation indicated. (B) Induction of Zta in the HeLa-Zta cell line by removal of tetracycline from the medium led to reduced expression of transfected Qp-CAT. The p53-CAT reporter served as a positive control for Zta expression. CAT activity is expressed relative to that of Qp-CAT in the presence of tetracycline (set at 100%).