Up mutations - more like consensus and make promoter stronger Sigma factor allows initiation of transcription by causing RNA polymerase holoenzyme to bind tightly to promoter. Local melting of DNA at -10 region forms open complex of promoter with RNA holoenzyme and is possible only in presence of sigma factor. Terminators Have inverted repeats which form stem-loop structure. Stem-loop in RNA causes RNA polymerase to pause just after making it. Pause may allow termination.
Pause occurs after U stretch.
Travels along mRNA at same speed as RNA polymerase. Rho has DNA-RNA helicase properties.