FIG. 6.

Transgenic expression of AL2 and L2 reduces genome-wide cytosine methylation. The histograms illustrate relative incorporation of dCTP observed in methylation-sensitive extension assays. DNA was obtained from dex- or water (mock)-treated Arabidopsis plants containing dex-inducible AL2 or L2 transgenes, digested to completion with MspI, and incubated with [³²P]dCTP and Taq polymerase to allow single-nucleotide extension (see text). Increased incorporation reflects enhanced MspI cleavage due to reduced methylation. Assays were performed with DNA from three individual plants from each of two independent AL2 transgenic lines (AL2-L6 and AL2-L7) (A) or three individual plants from each of two independent L2 transgenic lines (L2-L6 and L2-L8) (B). Mock treatment assays contained DNA from three or four plants from the same transgenic lines. Asterisks indicate significant differences between dex- and mock-treated samples at the 95% (*) or 99% (**) confidence level, as determined by Student's t test.