Fig. 7. Proposed model for ATR-PrimPol-mediated RST under KRASG12V-induced RS.
a Left, KRASWT cells (H3122, H1975, H1819) and KRASG12mut cells (H358, A427, H2009) were incubated for 2 days. The indicated proteins expression levels were analyzed by western blot analysis. Right, quantification of each expression level. The results represent the means ± SEM of three cells. Unpaired t-test. b Left, Dot plot and mean of fork speed in KRASWT cells and KRASG12mut cells transfected with 1 nM of siControl or siPPol#5 for 24 h as shown in (S7b). Representative result of two independent reproducible experiments are shown. Black lines indicate the mean; n = 200; two-tailed Mann–Whitney t-test. Right, PrimPol KD fold change in fork speed. The results represent the means ± SEM of three cells. two-tailed unpaired t-test. c High expression of both ATR and PrimPol is associated to poor prognosis of LUAD patients. Overall Survival (OS) according to ATR and PrimPol mRNA expression from totally 199 of LUAD patients harboring KRASWT and KRASmut were sanalyzed. Log-rank p-values are shown. d In the early step of KRASG12V expression, KRASG12V induces transcription-dependent locally compacted heterochromatin region mediated by H3K27me3, leading to RS. When cells express normal level of ATR, replication forks stall, causing incomplete replication. In contrast, when cells express high level of ATR, ATR-PrimPol pathway functions as a regulatory module at replication forks to complete replication by promoting repriming, allowing cells to survive under KRASG12V-induced RS with acquiring genomic instability. All source data are provided as a Source Data file.