Fig. 1: Polymerase usage following HR-restart.

a Schematic of the RTS1-rRFB locus on chromosome II. The positions of the directional RTS1 and rRFB barriers are shown as red and orange, respectively. The thick bar represents the directionality of fork arrest. ARS autonomously replicating sequence. The direction (see panel b) of unperturbed and perturbed replication at this locus is indicated by the thickness of arrows underneath. b Pu-seq traces of the ChrII locus. Top two traces: RTS1 barrier activity off (rtf1-d). Bottom two traces: RTS1 barrier activity on (rtf1⁺). Left: the usage of Pol δ (blue) and Pol ε (red) are shown on the Watson and Crick strands. Note the switch from Pol ε to Pol δ on the Watson strand at the RTS1 site is indicative of a change in polymerase usage on the leading strand when RTS1 barrier activity is on. Right: The same traces overlaid with data for Pol α (green). Pol α data is not to scale, see Methods section. c Chromatin immunoprecipitation of Rpa3-GFP at the indicated positions (relative to base 1 of the RTS1 sequence) in unsynchronised cells with either rnh1⁺ rnh201⁺ (WT) or rnh1-d rnh201-d backgrounds. Data presented are relative to the ade6⁺ control locus. n = 3 biological repeats. Error bars: standard deviation of the mean. d Chromatin immunoprecipitation using the S9.6 antibody in wild-type cells synchronised in G2 and released into S phase. n = 3 biological repeats. Error bars: standard deviation of the mean.