HDAC2 and viral infectious disease: To test the role of the E1A-HD2 fusion protein during viral infection, we inserted the E1A-HD2 gene into an oncolytic adenovirus (serotype 5) with Tcf-binding sites in the E1A, E1B, E2 and E4 promoters and deletion of the NF1, NFκB and AP1 sites in the E3 promoter [12] (Figure 2A).