Figure 2.

RNA primer exchange is induced by holo E. coli RNA polymerase. As indicated at the top of each lane, RNA–DNA bubble- duplex constructs were incubated with buffer (lanes 1 and 2) or with either the holo (lanes 3–5) or core (lanes 6–8) forms of E. coli RNA polymerase in the presence or absence of NTPs and of an RNA trap, and the products obtained were resolved by nondenaturing gel electrophoresis (see Materials and Methods). The band positions of the RNA primer and of RNA Products 1, 2, and 3 are indicated on the right side of the gel.