Fig. 6. Presence of 35Spro-NOSpro-Sense or -Antisense constructs does not trigger methylation of the target NOSpro. The intact sense construct was integrated in three independent tobacco transformants (A, left) and the antisense construct in four (A, right) as indicated by the presence of EcoRI (E) fragments of the expected sizes (arrowheads; first lanes of each panel). The SacII (S) site in the NOSpro was largely unmethylated in the sense plants (A, left), as indicated by the conversion to the smaller fragment after an ES double digest (second lanes of each panel). The SacII site was slightly methylated in several antisense plants (A, right), as indicated by the less than complete conversion to the smaller fragment following an ES double digest (second lanes of each panel). The significance of this methylation is not known. (B) The target NOSpro, which was the same in all lines, remained unmethylated in the presence of the transcribed sense (B, left) and antisense (B, right) constructs. Digests and explanations as in Figure 3C. Size markers are shown to the right.