Pro transgene mRNA expression in Pro[s] and Pro[a/s] plants. (Left) Total RNA from nontransgenic (NT), Pro[s]1, Pro[s]3, and Pro[s]5 tobacco plants probed for Pro sense mRNA. (Right) Nontransgenic (NT), Pro[a/s]1, and Pro[a/s]4 tobacco plants probed for antisense Pro mRNA. Both filters were also probed for actin mRNA (see Materials and Methods) for details.