Fig. 7
From: Visualizing translocation dynamics and nascent transcript errors in paused RNA polymerases in vivo
Transcriptional pauses and errors frequently occur at CpG sequences in vivo. (a) G-to-A error at the 3′ RNA end induces backtracking of RNAP in the C−1G+1 motif. These pauses are rescued and the errors are corrected by Gre factors. In the absence of Gre factors, the backtracked RNAP imposes a strong barrier to a replicating DNA polymerase (DNAP) leading to double-strand DNA breaks [22, 24]. (b) The PIE of the non-template DNA in the ΔgreAB, which is composed of 1,555 pause sites identified by parameters P(0.9, 50). The pre-translocated RNAP (gray oval) and the RNA-DNA hybrid are shown. (c) The 3′-penultimate C residue in the nascent RNA is favored when a G-to-A error(s) occurs at the 3′ G residue in ΔgreAB cells. The two groups for the PIE are shown: the left-side group represents reads containing ≥1 G-to-A errors at the G−1 (n = 127) and the right-side group represents the reads containing no error at the G−1 (n = 162). For panels B and C, 18 nt reads were used