(a) Co-localisation of p97 with CPDs in human cells. Mild expression of myc-tagged p97 (wild-type or p97 EQ) was induced with doxycycline (+Dox). Cells were probed 15 min after UV irradiation through micropore filters, whereby endogenous p97 was detected with anti-p97 antibodies and p97-myc with anti-myc antibodies. Scale bar, 10 μm. (b) UV-induced p97 re-localisation shown as quantitative ratio of fluorescence at CPDs against surrounding nuclear areas (200 nuclei from two independent experiments); error bars, s.e.m, ***P<0.001 relative to wild-type (the unpaired two-tailed t-test was used for all P-value determinations). (c) Reduced recruitment of myc-p97 EQ to CPDs after treatment with MG132 or siRNA targeting the indicated cullins; siNC, non-coding control. (d) Quantification of p97 EQ at CPDs over three experiments (>300 nuclei), ***P<0.001 relative to siNC control (unpaired two-tailed t-test). (e) Increased K48-linked ubiquitin after treatment with siRNA targeting p97, CUL4A/B or DDB2. (f, g) Quantification (>300 nuclei from three experiments) of K48-linked ubiquitin in nuclei overall and at lesion sites, respectively.