Figure 7.

ResT promotes fork regression. (A) Fork regression assay using a synthetic replication fork with homologous arms. Leading and lagging arm partial duplexes are annealed with ResT. The resulting replication fork mimic has homologous arms but a 5 nt heterology on each template strand at the ss-dsDNA junction inhibits spontaneous branch migration. ATP^.Mg²⁺ is added to induce ResT's helicase activity. (B) 8% PAGE 1× TAE/0.1%SDS gel analysis of fork regression promoted by wild type ResT and ResT (Q181A). After a 10 min annealing step, fork unwinding was induced by addition of ATP^.Mg²⁺ (or ATP-γ-S^.Mg²⁺). The possible products of fork unwinding were loaded as markers M1-5. The structure of the markers is indicated in the legend. The partial duplex arm substrates were present at 15 nM and ResT at 37 nM.