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. 2023 Oct 6;24(19):14956. doi: 10.3390/ijms241914956

Figure 3.

Figure 3

Dose-dependent regulation of DSB repair pathway choice. (A,B) Idealized dose response curves of γ-H2AX and RAD51 foci formation depicting the linear increase of γ-H2AX foci with increasing radiation dose and the saturation of RAD51 foci at higher IR-doses. The plots show fictive data points based on previously published results. (C) The numbers of RAD51 and γ-H2AX foci are used to calculate their ratio that indicates the fraction of DSBs processed by HR (HR repair, %). It is evident that HR contributes more to DSB repair at low IR doses, while its contribution at high doses is reduced. (D) Diagram showing estimates of the relative involvement of the different DSB repair pathways with increasing DSB-load. It is evident that c-NHEJ is the dominant repair pathway at medium and high DSB-loads, while HR is engaged at low DSB loads. Alternative forms of DSB repair gain ground when HR is suppressed at high doses. Moreover, under conditions of excessive DNA end resection (high-DSB load), SSA is promoted and significantly contributes to the repair of DSBs.