Figure 8.—

Analyses of complete and incomplete silencer transcripts. (A) Five RNAi-37 clones (nos. 1–5), which show distinctive silencing efficiencies, were chosen. A spotting test was carried out using plates containing various concentrations of spectinomycin. (B) Detection of the silencer transcripts. In Northern blot analyses, a membrane was first hybridized with the 5′-terminal sense-aadA RNA probe, which recognized the almost completely transcribed products (top). The probe was stripped and a second hybridization with the 3′-terminal antisense-aadA RNA probe, which hybridized with complete and incomplete transcripts of the silencer DNA, was carried out (middle). Finally, the same membrane was hybridized with a ble probe to ensure equal loading of total RNA (bottom).