Skip to main content
. 1998 Aug 18;95(17):9837–9842. doi: 10.1073/pnas.95.17.9837

Figure 5.

Figure 5

Inhibition of IRF-3-mediated activation of the IFNA4 promoter by E1A. (A) REF cells were cotransfected with 2.0 μg of plasmids expressing IRF-1, IRF-3, or its mutants, 2 μg of IFNA4/CAT reporter plasmid, and 100 ng of pCMV-β-galactosidase in the presence and absence of E1A (2.0 μg) or E1A (Δp300) mutant. (B) The synergistic activation of IFNA promoter by IRF-3 overexpression and NDV infection did not circumvent E1A-mediated suppression. Transfection was carried out as described in A, and cells were infected 24 hr posttransfection with NDV for 16 hr as described in Materials and Methods. (C) Overexpression of p300 partially restored the IRF-3 activity from suppression by E1A. REF cells were transfected with 1.5 μg of IFNA4/CAT, 100 ng of pCMV-β-galactosidase, 1.2 μg of IRF-3 and E1A expressing plasmids, and increasing amounts (0, 0.5, 1.5 μg) of p300 expressing plasmid. (Inset) Western blotting. Expression of IRF-3 in REF cells cotransfected with IRF-3 and p300 (lanes 1–3) and E1A (lane 2) and infected with NDV (lane 3). (D) Induction of IFNA4/CAT by IRF-3 was suppressed by the cotransfection of carboxyl terminus of CBP (amino acids 1992–2441). Two micrograms of IFNA4/CAT, 100 ng of pCMV-β-galactosidase, and 1.5 μg of IRF-3 expressing plasmids were cotransfected with 0, 2, or 4 μg of Δ 5′ CBP plasmid. The CAT assay was done as described above.