Unusual diversity in alpha-amanitin sensitivity of RNA polymerases in trichomonads.
Previous studies in the parasitic protist Trichomonas vaginalis have revealed that protein coding genes are transcribed by an alpha-amanitin-resistant RNA polymerase (RNAP) II. To investigate whether this unusual property is a general characteristic of trichomonads, we addressed the physiology of RNA synthesis in lysolecithin-permeabilized cells. Unlike in T. vaginalis, RNAP II in Tritrichomonas foetus was highly sensitive to the inhibitor alpha-amanitin. On the other hand, RNAP III, identified by its sensitivity to the specific inhibitor tagetitoxin, was found to be resistant to alpha-amanitin in Tritrichomonas foetus, but showed a typical intermediate sensitivity in T. vaginalis. Extension of this study to an additional seven trichomonad species confirmed this genera specific pattern of alpha-amanitin sensitivity and highlighted an unusual diversity in RNAPs among trichomonads, a closely related group of unicellular eukaryotes.
Vanácová
S
S
Department of Parasitology, Faculty of Science, Charles University, Vinicná 7, 2 128 44, Prague, Czech Republic.
Tachezy
J
J
Ullu
E
E
Tschudi
C
C
D000546:Amanitins / Q000494:pharmacology*; D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects; D003998:Dicarboxylic Acids / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D009943:Organophosphorus Compounds / Q000494:pharmacology; D012319:RNA Polymerase II / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016053:RNA, Protozoan / Q000096:biosynthesis*; D014158:Transcription, Genetic; D016834:Trichomonadida / Q000187:drug effects / Q000201:enzymology*; D014246:Trichomonas vaginalis / Q000187:drug effects / Q000201:enzymology*; D016835:Tritrichomonas foetus / Q000187:drug effects / Q000201:enzymology*
D000546:Amanitins; D003998:Dicarboxylic Acids; D004791:Enzyme Inhibitors; D008244:Lysophosphatidylcholines; D009943:Organophosphorus Compounds; D016053:RNA, Protozoan; C062221:tagetitoxin; D012319:RNA Polymerase II