Transcriptional activity of human papillomavirus type 16 variants having deletions in the long control region

Transcription of the E6 and E7 viral oncogenes of human papillomavirus (HPV ) type 16 is regulated by the P97 major early promoter, and enhancer and si lencer elements found in the long control region (LCR). In this study, we t ested the transcriptional activity of natural HPV 16 variants having long d eletions in the LCR. The HPV 16 LCR regions were amplified from invasive ce rvical cancer specimens, and cloned into the reporter vector pALuc. Transcr iptional activity of the different clones was measured by luciferase test a fter transient transfection into HeLa cells. The deletions found in the LCR encompassed parts of the enhancer and either the YY1-specific silencer alo ne or together with the CDP-specific silencer. The transcriptional activity of these deletion variants were usually reduced compared with that of the corresponding full-length clones. However, a deletion variant lacking the w hole enhancer and both silencer regions retained substantial enhancer activ ity on the P97 promoter. These results point to the existence of a novel co ntext-dependent enhancer element in the 5 ' LCR of HPV 16. (C) 2001 Elsevie r Science Ltd. All rights reserved.