Figure 3.

Northern analysis of N-gene expression. Top, Ethidium bromide-stained gel pattern. Bottom, Pattern of fluorescent bands following hybridization of the gel shown in the top frame to the DIG-labeled PCR product shown in Figure 1. Numbers and arrows on the right indicate the positions of RNA size markers. Lanes were loaded with RNA extracted of a leaf from non-inoculated tobaccoⁿⁿ (lane 1), a leaf from TMV-infected tobaccoⁿⁿ (lane 2), a locally infected leaf of tobacco^NN (lane 3), a leaf from noninoculated tobacco^NN (lane 4), and a systemic (noninfected) leaf from TMV-infected tobacco^NN (lane 5).