FIGURE 1.

RPB9 deletion has a minor effect on the catalytic properties of pol II. A, design of the assembled TEC7–50, TEC7–65, and TEC20–65. RNA is colored in red, and the sequences of the RNA primers for the TEC assembly are underlined and described in supplemental Table 2. B, bulk elongation assays. TEC7–50 was walked to position +9 with 5 μm each of GTP and ATP (TEC9–50, indicated in green), washed, and incubated with 2 μm of all four NTPs for various time intervals. The pause sites are indicated by gray boxes. C, time course of CTP incorporation at positions +10 and +23 of the transcript by TEC7–65 and TEC20–65, respectively. Black symbols and lines show the data set for WT pol II, and red symbols and lines represent pol IIΔ9. The curves represent a single exponential fit of the experimental data and the apparent rates (k) are shown for each reaction. Note that for the experiments described in the legends for Figs. 1C and 5, TEC9–65 and TEC22–65 were chased with CTP or with a mixture of CTP and ATP, respectively. The presence of ATP in the chase mixture does not affect CTP incorporation kinetics by TEC22–65.