FIG 1.

Knockdown of ATR in cells that maintain viral episomes blocks HPV episome maintenance and amplification upon keratinocyte differentiation. (a) Western blot analysis of p-ATR, ATR, involucrin, and GAPDH levels in HFKs, HPV31, and HPV31-positive CIN612 cells differentiated in high-calcium media for the indicated times (in hours). (b) Western blot analysis of ATR and GAPDH levels in CIN612 cells transiently transduced with five different shRNA lentiviruses against ATR. (c) Southern blot analysis for HPV31 episomes in CIN612 cells with transient ATR knockdown following differentiation in high-calcium media for the indicated times (in hours). (d). Western blot analysis of ATR, ATM, and GAPDH protein levels in mock, scrambled control, and two stably selected ATR knockdown CIN612 cells upon differentiation in high-calcium media for 72 h. (e) Southern blot analysis for HPV31 episomes in CIN612 cells with stable ATR knockdown following differentiation in high-calcium media for the indicated times (in hours). The two panels are from the same blot. All results are representative of observations from two or three independent experiments. IB, immunoblotting.