Human papillomavirus type 33 in a tonsillar carcinoma generates its putative E7 mRNA via two E6* transcript species which are terminated at different early region poly(A) sites.
Human papillomavirus type 33 (HPV-33)-specific early region transcripts in a tonsillar carcinoma were analyzed by using the RNA polymerase chain reaction method. A total of five cDNA species including species with potential to encode E6*I, E6*II, and E6*III, could be identified. As determined by 3' cDNA end mapping, one E6*I cDNA species was found to utilize a novel early region poly(A) site and was polyadenylated at or near the putative initiation codon of the E1 open reading frame (ORF). Compared with the HPV-16 and HPV-18 E6* mRNAs, the HPV-33 E6*I and E6*II species utilize different splice acceptor sites, the latter being localized within the E7 ORF. Furthermore, HPV-33 E6* mRNAs were found to contain a short overlapping ORF resulting in alternative coding potentials if translation were to start at an internal AUG codon within the E6 region. These results indicate that like HPV-16 and HPV-18, HPV-33 generates E6* mRNAs which may serve as efficient mRNAs for E7. However, HPV-33 has the ability to generate its putative E7 mRNAs by the utilization of two early region poly(A) sites, which offers the possibility of expressing E7 in different ways.
Snijders
P J
PJ
Department of Pathology, Free University Hospital, Amsterdam, The Netherlands.
van den Brule
A J
AJ
Schrijnemakers
H F
HF
Raaphorst
P M
PM
Meijer
C J
CJ
Walboomers
J M
JM
D001483:Base Sequence; D002874:Chromosome Mapping; D004277:DNA, Single-Stranded; D006801:Humans; D008969:Molecular Sequence Data; D027383:Papillomaviridae / Q000235:genetics*; D011061:Poly A; D016133:Polymerase Chain Reaction; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism*; D014067:Tonsillar Neoplasms / Q000382:microbiology*; D014158:Transcription, Genetic; D014412:Tumor Virus Infections / Q000235:genetics*
D004277:DNA, Single-Stranded; D012333:RNA, Messenger; D011061:Poly A