[Selective inhibition of the synthesis of AMP-rich RNA by α-amanitin in higher plant cells].

The effect of α-amanitin on the synthesis of AMP-rich RNA has been investigated. After incubation of freely suspended callus cells of parsley with the toxin and pulse labelling (30 min) with (32)P-orthophosphate, the high AMP content of the RNA component eluted from MAK columns behind the 25 S-RNA disappears. The base ratio of this RNA becomes ribosomal (CMP 20.1, AMP 26.5, GMP 28.4, UMP 25.0). Polyacrylamide gel electrophoresis of the high molecular RNA shows that radioactivity is incorporated only into the 32 S-RNA. At higher α-amanitin concentrations the total nucleic acid synthesis is reduced. In this case only the high molecular RNA (32 S-RNA) is produced.