Figure 21-5: A. Consensus sequence of the N4 virion RNA polymerase promoters. (X:X) indicates non-conserved positions in the inverted repeats. (+1) indicates the site of transcription initiation. Boxed sequences are required for high hairpin stability and extrusion. B. Proposed model for the pathway of vRNAP-promoter utilization. The stoichiometry of Eco SSB in the activated complex is unknown.