Fig. 7

FAAP100 is required to protect nascent DNA strands against degradation. A Experimental scheme and ratios of CldU:IdU tract lengths in MEFs under unperturbed conditions or after exposure to 2 μM APH or 0.5 mM HU for 4 h. At least 200 DNA fibers were scored per group. Three independent experiments were conducted. B Model of FA pathway functions in the resolution of transcription–replication conflicts (TRCs) in PGCs. When TRCs occur, the FA pathway is activated to resolve R-loops and protect nascent DNA strands from uncontrolled nucleolytic degradation, thus safeguarding PGC genome stability during the active proliferation period. In the absence of FAAP100, the nonfunctional FA pathway leads to R-loop accumulation and replication fork collapse, further resulting in catastrophic genome instability and proliferation defects in PGCs. Data are shown as the mean ± SEM (A). Unpaired two-tailed Student’s t-test (A), ns, not significant, *P < 0.05 and ***P < 0.001