Figure 6. Methylation of CpG sites in the vav1 promoter impairs expression of the reporter gene in various cell lines.

(A) Le2 plasmid, either un-treated or methylated by CpG methyltransferase (M.SssI), was incubated with HpaII and analyzed on a gel. The plasmid treated with M.SssI was not digested by HpaII, indicating that methylation was successful. (B) Unmethylated or methylated Le2 was transfected into Jurkat T cells, U937 myeloid cells and H441 lung cancer cells. The luciferase activity of these plasmids was measured 24 hr after transfection. Fold induction of luciferase activity was calculated relative to the activity in cells transfected with unmethylated Le2. Each point is the mean of three experiments. (***) indicates p<0.01, unpaired student T test.