Figure 3.

Primer extension assay of the Pcop1-Pcop2, Pδ, Pω, and Pαβ in the absence or presence of the ω protein. The supercoiled plasmid DNA (2 nM) was incubated with 20 nM of σ^ARNAP in the absence or presence of increasing concentrations of ω protein (15, 30, 60, and 120 nM) and subjected to in vitro transcription followed by primer extension. In A, Pcop1-Pcop2; in B, Pδ; in C, Pω; and in D, Pαβ as a nonspecific control. The lengths of the cDNAs obtained in the presence or absence of ω are indicated. The length of the standards in the region of interest are indicated. −, absence of protein ω.