Overview Process initiation RNAp binds the template DNA strand at the promoter site with the help of transcription factors elongation RNAp synthesizes the mRNA strand in 5' → 3' direction reads template strand in 3' → 5' direction eukaryotic RNAps transcribe introns as well as exons RNAp inhibited by alpha-amanitin (ingestion of the amanita phalloides mushroom) termination prokaryotes two mechanisms rho-dependent rho protein binds the mRNA causes RNAp to fall off rho-independent mRNA has a GC-rich segment that naturally forms a hairpin causes RNAp to fall off eukaryotes transcription continues past the gene and eventually falls off Mono/polycistronic monocistronic = mRNA codes for 1 protein eukaryotes only have monocistronic mRNA polycistronic = mRNA codes for >1 protein e.g. bacterial lac operon