Transcription of Episomal Papillomavirus DNA in Human Condylomata Acuminata and Buschke-Lowenstein Tumours

Abstract

SUMMARYCondylomata acuminata and Buschke-L6wenstein tumours were analysed for the presence of human papillomavirus (HPV) transcripts. HPV DNA and RNA sequences were present in all 13 samples investigated. Ten contained HPV6 and three harboured HPVll. The HPV genomes were found exclusively as extrachromosomal circular molecules. In six biopsy specimens, viral RNA transcripts were not detectable by Northern blot analysis but could be demonstrated in dot blots. From seven HPV6-containing samples it was possible to obtain sufficient amounts of undegraded mRNA. We have found consistently one major species (1.4 kb). Less prominent species of 1.7, 1.85, 2.7 and 3.2 kb, respectively, were also detected. The 3' ends of the HPV6 mRNAs were located between nucleotides 3917 and 4441 in the putative early region and between nucleotides 7232 and 7696 in the putative late region. The arrangement of the 3' termini and the adjacent coding areas within the HPV6 genome show that the RNA species are transcribed from one DNA strand.

Physical State and Biological Activity of Human Papillomavirus Genomes in Precancerous Lesions of the Female Genital Tract

“…Owing to the low amount of RNA available (3 to 10 gg total RNA per tumour), RNA analysis was performed by the procedure of synthesis of 32p-labelled cDNAs by reverse transcription of the polyadenylated RNAs present in the tumour RNA samples, as described recently elsewhere (Lehn et al, 1984). Total RNA (3 to 10 gg) was incubated at 37 °C in 200 I-tg/ml oligo(dT), 30 ~tM-32p-labelled deoxynucleoside triphosphates (Amersham, 400 Ci/mmol), 100 ~tg/ml actinomycin D, 50 mM-Tris-HC1 pH 8.3, 6 mM-MgC12, 140 mM-KCI and 6 to 18 units of avian myeloblastosis virus reverse transcriptase (Life Sciences, St Petersburg, Fla., U.S.A.).…”

“…HPV DNA sequences have been found in the majority of these lesions; however, there are few data available on the important questions of physical state and transcription of these genomes. The genomes of HPV types 6 and 11 are present exclusively as extrachromosomal (episomal) DNA molecules in benign lesions of the genital tract (Gissmann et al, 1982;Lehn et al, 1984), whereas HPV16 genomes were shown to be integrated into the host genome in cervical carcinoma biopsies (Dfirst et al, 1985;Lehn et al, 1985;Lehn & Sauer, 1985). Both in benign tumours and in some carcinomas, the HPV genomes were transcriptionally active (Lehn et al, 1984(Lehn et al, , 1985Lehn & Sauer, 1985;Schwarz et al, 1985) while in contrast HPVI6 DNA was not expressed in some of the cervical carcinoma biopsy specimens screened (Lehn et al, 1985;Lehn & Sauer, 1985;Schwarz et al, 1985).…”

Different human cervical carcinoma cell lines show similar transcription patterns of human papillomavirus type 18 early genes.

“…The generation of the fusion transcripts is a direct consequence of the integration mode of HPV18 DNA in the cells since disruption of the HPV18 early region within the El -E2 segment removes part or all of the 3'-terminal processing signals for maturation of the early mRNAs from the upstream transcribed E6/E6*-E7-El sequences. These 3' signals include a splice acceptor site located in the E2-E4 segment and a polyadenylation signal at the 3'-end of the early transcription unit which has been identified in early mRNAs of BPV1 (Stenlund et al, 1985;Yang et al, 1985), CRPV (Danos et al, 1985;Nasseri and Wettstein, 1984) and HPV6b (Lehn et al, 1984). Integration within El -E2 and synthesis of viralcellular fusion transcripts may be necessary in the malignant tumor cells in order: (i) to disrupt intragenomic regulation mechanisms for HPV gene expression, (ii) to abolish expression of the 3' ORFs of the HPV early transcription unit, and (iii) to stabilize the mRNAs coding for the E6/E6*/E7 proteins thereby assuring expression of the viral functions necessary for maintenance of the malignant phenotype.…”

Transcriptional Activity of Human Papillomavirus Type 6 in Respiratory Tract Papillomata

“…Viral RNA in HPV-6-induced genital tract lesions has been examined. Lehn et al (1984) were able to detect viral transcripts in seven condylomata acuminata and Buschke-LSwenstein tumours. They found one major transcript of 1.4 kb and less abundant transcripts of 1-7, 1.85, 2.7 and 3-2 kb.…”

“…No hybridization to this size class was detectable in controls using RNA prepared from human liver, placenta or grossly normal respiratory epithelium. This 1200 nucleotide transcript may correspond to the 1.4 kb transcript seen by Lehn et al (1984) in HPV-6-containing condylomata acuminata, and to the El-E4 cDNA isolated by Nasseri et al (1987) from a genital wart induced by HPV-11. Their sequence analysis demonstrated a joining of part of ORF E1 to this region of E4, E5a and E5b.…”