title: Unique amanitin resistance of RNA synthesis in isolated nuclei from Amanita species accumulating amanitins.
abstract: In order to understand the basis upon which amanitin-accumulating species of Amanita are able to develop in the presence of these specific inhibitors of RNA synthesis, the in vitro RNA synthesizing activities of nuclei isolated from amanitin-accumulating species. Amanita hygroscopica (culture, derived from amanitin-accumulating carpophore) and A. suballiacea (carpophore), and from the non-accumulating species A. solitaria (culture) and A. brunnescens (carpophore) were tested for their sensitivities to alpha-amanitin inhibition. The nuclear RNA synthesizing activities obtained from both carpophores and cultures of non-accumulating organisms displayed significant sensitivities to alpha-amanitin, whereas those obtained from accumulating organisms displayed remarkable resistance to alpha-amanitin. The observed relationship between levels of amanitins in carpophores and resistance of the RNA synthesizing activities to inhibition by alpha-amanitin supports the hypothesis that amanitins may function as regulators of mRNA transcription in Amanita species.
mesh_terms: D000363:Agaricales / Q000187:drug effects*; D000545:Amanita / Q000187:drug effects* / Q000378:metabolism; D000546:Amanitins / Q000096:biosynthesis / Q000494:pharmacology*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002474:Cell-Free System; D004352:Drug Resistance, Microbial; D012319:RNA Polymerase II / Q000037:antagonists & inhibitors; D012331:RNA, Fungal / Q000096:biosynthesis*; D013045:Species Specificity
chemical_list: D000546:Amanitins; D012331:RNA, Fungal; D012319:RNA Polymerase II