(A) The IR and CPT survival defects of ctp1Δ cells are suppressed by eliminating Ku80. This rescue depends on Exo1.
(B) Recruitment of RPA to a DSB is reduced in ctp1Δ and mre11Δ strains relative to wild type. ChIP analysis of RPA (rad11-TAP) around an HO-induced DSB. Expression of HO endonuclease was controlled using the thiamine-repressible nmt1 promoter. Sites located 0.2, 2, 9 and 16 kb from the DSB were assayed for enrichment of RPA (see Figure 4 for map of probes). The act1 probe is included as a negative control. Microscopic analyses confirmed that >90% of the cells in all strains arrested division as a result of HO expression, confirming highly efficient cutting by HO endonuclease.
(C) Recruitment of RPA to a DSB is reduced in ctp1Δ and mre11Δ strains relative to wild type. Quantitative real-time PCR was used to measure enrichment of RPA at sites located 0.2 or 9 kb from the HO-induced DSB.