Figure 3. TYLCCNB, or βC1 expression, globally reduces cytosine methylation in the host genome.

The histograms depict the relative ³²P-dCTP incorporation observed in methylation-sensitive extension assays. DNA was obtained from mock inoculated or infected plants, digested with MspI, and incubated with ³²P-dCTP and Taq polymerase to permit single-nucleotide extension. Increased incorporation due to enhanced MspI cleavage indicates reduced methylation. (A) DNA was obtained from mock-inoculated plants, or plants inoculated with TYLCCNV or TYLCCNV + TYLCCNB. (B) DNA was obtained from mock-inoculated plants, or plants inoculated with PVX or PVX expressing βC1 protein (PVX-βC1). Both (A) and (B) represent data from two independent experiments. In each experiment, assays were performed in duplicate with DNA from three individual plants per treatment. Values represent means +/- SE. Double asterisks indicate significant differences between samples with and without TYLCCNB at the 99% confidence interval, as determined by Student's t test.