The DNA-binding domain of Zta is required for induction of MMP3 expression.

<p>(<b>A</b>) NPC cells were transfected with a vector plasmid (Vec) or plasmids expressing wild-type Zta or the DNA binding-defective mutants (Zdbm1 and Zdbm2) and then subjected to a ChIP assay. The antibodies used for immunoprecipitation (IP Ab) included an anti-Zta antibody and a control antibody (Ctrl). In the immunoprecipitants, the target DNA region (T) spanning AP-1 elements of the MMP3 promoter and the control DNA region (C) distant from the AP-1 elements were quantified by using real-time PCR. The ChIP results were expressed as “percentage of input”. (<b>B</b>) Cells were transfected with a vector plasmid or plasmids expressing wild-type Zta, Zdbm1 or Zdbm2. Protein expression of Zta and β-actin was examined by an immunoblotting assay (upper panel). Expression levels of MMP3 mRNA were measured by quantitative RT-PCR (middle panel). Concentrations of MMP3 protein in the cell culture supernatants were quantified by using ELISA (lower panel).