Skip to main content
. Author manuscript; available in PMC: 2023 Sep 27.
Published in final edited form as: Cell Rep. 2023 Jul 16;42(7):112792. doi: 10.1016/j.celrep.2023.112792

Figure 2. ATR prevents resection from PrimPol-generated gaps at ongoing forks.

Figure 2.

(A) Schematic representation of the nascent DNA degradation fiber assay.

(B and C) Cells were treated as in (A) with or without ATRi (VE-821, 10 μM) and MRE11i (Mirin, 50 μM) in (B), and with or without ATRi (VE-821, 10 μM) following 48 h siRNA knockdown of EXO1 in (C). Number (n) of fibers quantified >250 across two biological replicates. Significance was calculated using the Mann-Whitney Ranked Sum Test with ***p < 0.001, ****p < 0.0001.

(D and E) siRNAs against HLTF, SMARCAL1, and ZRANB3 (siTriple) (D) or PrimPol (E) were transfected 48 h prior to fiber analysis. Number (n) of fibers quantified >500 across three biological replicates. Significance was calculated using the Mann-Whitney Ranked Sum Test with ****p < 0.0001.

(F) U2OS cells were analyzed as in (E) except cells were treated for only 1 h with or without ATRi (VE-821, 10 μM) and HU (4 mM) followed by S1 nuclease digestion. Number (n) of fibers quantified >135 in each sample across two biological replicates. Significance was calculated using the Mann-Whitney Ranked Sum Test with *p < 0.05, ****p < 0.0001.

(G) Model for how nascent DNA is degraded at ongoing forks.