Prokaryotic Overview 1 type of RNA polymerase (RNAp) Structure α2ββ' core subunits Initiation σ (sigma) = initiation factor binds RNAp to DNA Termination ρ (rho) = termination factor Clinical importance inhibited by rifampin antibiotic actinomycin D antibiotic Eukaryotic Overview 3 types of RNA polymerase RNAp 1 synthesizes rRNA in nucleolus remember: rRNA is most abundant RNA; so it is #1 RNAp 2 synthesizes mRNA, snRNA in nucleus RNAp 3 synthesizes tRNA in nucleus remember: tee = three makes eukaryotic 5s rRNA Structure similar in structure to prokaryotes Initiation TFIID = initiation factor binds RNAp to DNA Termination translation continues far past gene and RNAp eventually falls off Clinical importance inhibited by α-amanitin poison in death cap mushrooms inhibits RNA polymerase 2 from synthesizing small nucleolar RNA and messenger RNA leads to acute liver and kidney failure actinomycin D chemotherapeutic