FIG 5.

Nbs1 is not necessary for HPV31 genome maintenance. (A) DNA was isolated at the indicated passages from CIN612 9E cells stably maintaining a Scramble shRNA (shScram) or Nbs1 shRNA (shNbs1) and analyzed by Southern blotting. Passage 22 (p22) represents the passage at which the CIN612 9E cells were transduced with the respective shRNAs. Each passage following transduction is represented by p22-#. Western blot analysis was performed on lysates harvested at each passage using an antibody to Nbs1 to demonstrate knockdown, as well as antibodies to Mre11 and Rad50. GAPDH served as a loading control. IB, immunoblotting. (B) Bar graph represents episome copy number quantified and averaged across the passages of cells containing Scramble shRNA (set at 1) compared to passages of Nbs1 shRNA-containing cells. The data represent the averages of four independent experiments. Densitometry was performed using ImageJ software. The statistical analysis was assayed by 2-tailed t test. Data are means ± standard errors.