FIG. 5.

In vitro transcription with ς⁷⁰ mutants from the tac and T4 uvsY promoters. Reactions contained RNA polymerase core enzyme and the indicated GST-ς⁷⁰ protein (0.5 pmol). Runoff transcripts were synthesized from a linear template containing either the tac promoter (A) (320-base transcript) or the T4 uvsY promoter (B) (221-base transcript, indicated by the arrow; the template was not T4 modified). Size standards (in bases) are indicated to the left of the gel. The heavy spot at the bottom left corner (just above the numeral 2) is a film artifact.