Skip to main content
. 2009 Sep 16;284(46):31658–31663. doi: 10.1074/jbc.M109.022764

FIGURE 2.

FIGURE 2.

Transcriptional mutagenesis. a, adenine misincorporation in EC A in the presence of CTP at different ratios (1 mm ATP, 5-min incubation). RNA products containing adenine (5900 Da) or cytosine (5924 Da) were identified by mass spectrometry (see “Experimental Procedures”). b, misincorporated adenine remains in the runoff (RO) RNA. EC A was incubated with NTPs (1 mm, 60 min) or with ATP (1 mm, 5 min), followed by incubation with NTPs (1 mm, 60 min) as indicated. Mass spectrometry identified runoff RNAs containing cytosine (10,393 Da) or adenine (10,417 Da). c, effect of the cleavage stimulatory factor TFIIS on RNA elongation with ECs B and C. Incubation with TFIIS for 5 min resulted in cleavage products (lanes 3, 10, and 11). The presence of NTPs (1 mm) increased runoff formation (lanes 6 and 14) independent of the order of addition (lanes 7, 8, 15, and 16). * and #, RNA impurities and a cleavage product after backtracking, respectively. Controls included incubations of fluorescent RNA with pol II (lanes 4 and 12) and of lesion-free ECs Bundamaged and Cundamaged with TFIIS (lanes 2 and 10).