To rule out the possibility that overexpression of ZNF804a results in artificial binding to DNA upstream for PRSS16 and COMT, we determined whether endogenous ZNF804a protein interacts with the same regions of PRSS16 and COMT. We performed ChIP assays using anti-ZNF804a antibody in untransfected neural progenitor cell cultures. Similar to ChIP results for the overexpressed ZNF804a protein ChIP for endogenous ZNF804a protein enriched DNA sequence within the PRSS16 (Figure 4a; 4.9±0.03%, p<0.05; n = 5) and COMT (Figure 4b; 4.2±0.06%, p<0.05; n = 5) promoter regions. Moreover, the enriched peaks were in the same locations for recombinant ZNF804a and endogenous ZNF804a. These results are consistent with ZNF804a contributing directly to the regulation of transcription.
