[The biological activities of the human papillomavirus type 16 E6/E7 cDNAs cloned from the SiHa cervical carcinoma cell line].
Both the spliced and unspliced E6/E7 mRNA species are transcribed from the viral genome of the high risk human papillomavirus 16, 18, and 31 (HPVs 16, 18 and 31) in uterine cervical carcinomas, but no spliced E6/E7 transcripts have been found in the low risk HPVs 6b and 11 in genital benign lesions. In this study, to examine the in vitro biological activities of the spliced and unspliced E6/E7 mRNAs of HPV16, we synthesized three HPV16 E6/E7 cDNAs, that is, cF (wt), c* I and c* II, for full-length E6/E7 mRNA, and two spliced mRNAs of E6*I/E7 and E6*/II/E7, respectively, from the cervical carcinoma cell line SiHa by reverse transcriptase PCR technique. We also constructed two cDNA mutants, cF (Do) and cF (Ac), which carry single point mutations at the splice donor site and the splice acceptor site, respectively. These E6/E7 cDNAs were cloned and tested for the ability to transform primary rat fibroblasts collaboratively with activated ras gene and to induce cellular DNA synthesis. c* I showed almost the same level of these activities as the subgenomic E7 fragment and cF (wt). The transforming activities of the splice site mutants, cF (Do) and cF (Ac), and of c*II were low compared to cF (wt) and none of these cDNAs showed any detectable abilities to induce cellular DNA synthesis. These results suggest that transcription of the E6* I/E7 mRNA is important for in vitro biological activities of the HPV16 E6/E7 region, possibly by high-level E7 protein production.
Tamada
Y
Y
Department of Obstetrics and Gynecology, Hokkaido University School of Medicine, Sapporo, Japan.
D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000138:chemical synthesis / Q000502:physiology*; D004279:DNA, Viral / Q000235:genetics*; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D027383:Papillomaviridae / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics*; D051381:Rats; D014162:Transfection / Q000235:genetics; D014170:Transformation, Genetic / Q000235:genetics; D014407:Tumor Cells, Cultured; D014412:Tumor Virus Infections / Q000382:microbiology*; D002583:Uterine Cervical Neoplasms / Q000382:microbiology*
D018076:DNA, Complementary; D004279:DNA, Viral; D012333:RNA, Messenger; D012367:RNA, Viral