Fig. 2: RNA–DNA hybrid formation after DNA fork collision.
From: RNA polymerase II is a polar roadblock to a progressing DNA fork
a Detailed view of a representative force-extension trace of the DNA fork unzipping through an elongating Pol II in the co-directional orientation, showing an extension shift, where the force profile follows that of the naked DNA but at a shorter extension. The dashed curve indicates the predicted force-extension curve for an unzipping fork encounter with a Pol II at the TSS. b Cartoon depiction of how an RNA–DNA hybrid leads to extension shortening in the co-directional orientation, with the hybrid forming on the leading strand. c RNA–DNA hybrid size, measured after the disruption of Pol II by the DNA fork, plotted against transcript size for the co-directional orientation. The dashed line indicates the predicted hybrid size if the entire transcript RNA is converted to a hybrid. (−) RNase T1, N = 22; (+) RNase T1, N = 17. d Detailed view of a force-extension trace of the DNA fork unzipping through an elongating Pol II in the head-on orientation, showing an extension shift, where the force profile follows that of the naked DNA but at a shorter extension. The dashed curve indicates the predicted force-extension curve for an unzipping fork encounter with a Pol II at the TSS. e Cartoon depiction of how the RNA–DNA hybrid leads to extension shortening in the head-on orientation, with the hybrid forming on the lagging strand. f RNA–DNA hybrid size, measured after the disruption of Pol II by the DNA fork, plotted against transcript size. The dashed line indicates the predicted hybrid size if the entire transcript RNA is converted to a hybrid. (−) RNase T1, N = 21; (+) RNase T1, N = 8. Source data are provided as a Source data file.
