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. 2008 Sep 2;118(10):3470–3477. doi: 10.1172/JCI35114

Figure 3. Egr-1 activates HSV-1 gene promoters by binding to its corresponding sequence in the promoter.

Figure 3

(A) The activities of the ICP27, ICP22/47, ICP4, and US6 promoters in SK-N-SH cells stably transfected with plasmids containing Egr-1 (Egr-1) or empty vector (vector). (B) The activities of the ICP27 promoter (ICP27) or ICP27 promoter with a mutated Egr-1–binding sequence (ICP27 mut) (top panel) and Western blot analysis of Egr-1 (middle panel) and α-tubulin (bottom panel) in 1 clone of SK-N-SH cells stably transfected with vector plasmid and 2 clones of SK-N-SH cells stably transfected with Egr-1 plasmid, clone numbers 4 (Egr-1 no. 4) and 11 (Egr-1 no. 11). The viral promoter activities in cells stably transfected with pCB6 were set at 100%. Data show mean ± SEM from 3 independent experiments, each done in duplicate. *P < 0.05; **P < 0.005, Student’s t test. (C) Binding of Egr-1 to its corresponding sequence in the ICP27 promoter assayed by ChIP-PCR assay. Egr-1 and DNA complex from cells mock transfected (mock) or transfected with plasmids containing the ICP27 (ICP27) or mutated ICP27 (ICP27 mut) promoter was precipitated by anti–Egr-1 antibody or control rabbit IgG. The precipitated DNA and genomic DNA (input) were subjected to PCR amplification using primers specific for both ICP27 and mutated ICP27 promoters. Data are representative of at least 2 experiments.