20.2 Eukaryotic RNA polymerases consist of many subunits Amanitin(more fully a-amanitin)is a bicyclic octapeptide derived from the poisonous mushroom amanita halloides; it inhibits transcription by certain eukaryotic rNa polymerases especially rna polymerase II 请莘大Amanitin (more fully a-amanitin)is a bicyclic octapeptide derived from the poisonous mushroom Amanita phalloides; it inhibits transcription by certain eukaryotic RNA polymerases, especially RNA polymerase II. 20.2 Eukaryotic RNA polymerases consist of many subunits