Figure 1.

Detection of HPV16 DNA in a keratinocyte cell culture (HPK IA) by Southern blot analysis at different time points after transfection. Ten picograms of HPV16 DNA excised from vector by BamHI digestion (7.9 kb) is included as a sensitivity marker for hybridization and represents approximately one viral copy per cell. Total genomic cell line DNA was digested with EcoRI or BamHI. The 7.3-kb EcoRI band and the 7.9-kb BamHI band are characteristic for cleavage of the full length HPV16 genome whereas high molecular mass EcoRI and BamHI bands (arrowheads) are indicative of viral integration.