Figure 6.

Primer extension showing lesions in 28S rRNA in multiple tissues. a: Total RNA was purified from blood, brain, kidney, lung, liver, and spleen of mice instilled with saline (lanes 1 to 6) or 20 μg of ricin/100 g body weight (lanes 7 to 12) and sacrificed 48 hours after instillation. Reverse transcription was performed using a primer that binds near the known ricin-mediated depurination site of the 28S rRNA10,13 to detect the presence of stalled transcripts. Truncated transcripts were detected from all ricin-treated tissues except brain. b: Mice were instilled with 2 μg of ricin/100 g body weight and blood, kidney, lung, liver, and spleen were harvested at times from 6 hours to 14 days, as indicated. Total RNA was purified and primer extension was performed as described above.