Figure 2.

RNA analysis. (A) RNase protection reveals the ≈0.3-kb NOSpro dsRNA transcribed from the silencer NOSpro IR. NT, normal untransformed plants. (B) Total RNA used in A probed with an actin probe from tobacco and an eIF-4A probe from Arabidopsis as loading controls. (C) Detection of NOSpro short RNAs (sense probe) produced by means of dsRNA cleavage. Identical results were obtained with an antisense probe. (D) Nuclear run-on analysis demonstrating transcriptional down-regulation of the NOSpro–NPTII target gene in the presence of the silencing locus, which encodes HPT and NOSpro dsRNA. A constitutively expressed ribulose 1,5-bisphosphate carboxylase (rubisco) gene was used as a control. Positive controls in A and C were prepared from tobacco plants transformed with the 35Spro–NOSproIR construct.