Fig. 4

Smarcad1 and Trim28 depletion has an additive effect on MLV upregulation (A) Double KD was achieved by lentiviral infection carrying Smarcad1 shRNA, puromycin selection and then Trim28 shRNA lentiviral vector with G418 selection. Depletion was verified by RT‒qPCR, normalized to UBC control gene. Data are the mean ± s.e.m, n = 3 and a nonparametric Wilcoxon test was employed for comparisons to 1 (WT expression ratio). *P < 0.05. **P < 0.01. ***P < 0.001. B The percentage of GFP-positive cells 14 days after shSmarcad1 infection, 7 days after infection by MLV-PBSpro, and 5 days after shTrim28 infection. Data are the mean ± s.e.m, n = 3. All values significantly differ (black *P < 0.05) from 1 using a nonparametric Wilcoxon test. The double KD was significantly different from the single KDs using the Mann–Whitney U Test (orange *P < 0.05). C Expression levels of selected ERVs following Smarcad1 and/or Trim28 depletion were measured by RT‒qPCR. Data are the mean ± s.e.m, n = 3–5. Values significantly differ (*P < 0.05) from 1 using a nonparametric Wilcoxon test. D The percentage of GFP-positive cells 27 days after shSmarcad1 infection, 20 days after infection by MLV-PBSpro and 5 days after shTrim28 infection. Data are the mean ± s.e.m, n = 3. The P value between different KD lines was calculated using Mann–Whitney U Test, (orange *P < 0.05). Only the double KD values significantly differ (black *P < 0.05) from 1 using a nonparametric Wilcoxon test