Structure, DNasel hypersensitivity and expression of integrated papilloma virus in the genome of HeLa cells

Abstract

Three integrated copies of human papilloma virus-18 (HPV-18) have been identified in HeLa DNA as Hind111 bands. HPV-18 has no Hind111 restriction site in its genome. The three segments: A, 8.4 kb; B, 7.9 kb and C, 5.8 kb, have an incomplete viral genome. All of them have most of the 1.1-kb BumHl non-coding fragment of HPV-18, which seems to contain the viral origin of replication and regulatory elements. Two of the segments (A and B) have a common 5'-end break-point in the viral genome within the L2 open reading frame (ORF). In both segments the second early transcriptional unit of the virus (E6, E7 and El) is structurally conserved in a new environment. The 3'-end break-point for segments A and B is within the E2 ORF. Segment C has the L2 and L1 ORF but none of the genes of the early region. Segments A and B have a specific DNaseI-hypersensitive site located in the E7/E1 region. The nucleotide sequence of this region has twelve papova virus enhancer-like consensus sequence (5'-TCCACANA-3') and a double inverted repeat with fixed spacing capable of forming a hairpin loop. Two viral RNA transcripts of 4.8 kb and 1.7 kb have been detected in poly(A)-rich RNA. The larger transcripts hybridizes to E6, E7 and El ORFs as well and has 2.4 kb of host sequence in its 3' end. The smaller transcript hybridizes with E6 and E7 ORFs and the beginnig of El, the final 0.7 kb of El are not detectable. No transcripts have been detected carrying E2, E4, E5, L2 and L1 ORF sequences. The transcripts are derived from segments A or B. Segment C is not transcriptionally competent.A T Papilloma viruses are members of the papova virus family but have not received as much attention as other members of this group (simian virus 40, polyoma), because originally they were not associated with any cancer and were difficult to propagate in cell culture. The better-characterized morphological alterations induced by these viruses are papillomas or fibropapillomas (common warts), an abnormal cellular proliferation in the stratified epithelia [l, 21. More recent information has demonstrated a close association between the presence of this virus and malignant growth in the same area. The best-characterized association was detected in cervical carcinomas in rabbits [3, 41 and more recently in humans Papilloma viruses can infect a wide variety of mammals in a species-specific manner [l]. Many viral types have been identified so far and in spite of their high variation at the nucleotide level their gene organization (Fig. 1) is remarkably conserved (for recent review see [17]). These viruses have circular DNA molecules of approximately 7.5 -8.5 kb. They contain a region considered regulatory and an origin of replication [18], also called the non-coding region or long control region, followed by an early region consisting of eight open reading frames (ORF) and a late region with two ORFs [ll, 19-22]. The best-characterized virus of this family is bovine papilloma virus 1, BPV-1 [22]. Most of the studies [5-161.

Genomic instability of the host cell induced by the human papillomavirus replication machinery

“…( D ) Analysis of expression of HA epitope‐tagged E1 of HPV6b (lanes 1 and 2), HPV11 (lanes 3 and 4), HPV16 (lanes 5 and 6) and HPV18 (lanes 7 and 8) 48 h after transfection with 3F10‐HRP antibody. ( E ) Schematic representation of the episomal HPV18 genome and the integrated HPV18 in HeLa cells (Lazo, 1987; Meissner, 1999). Cellular DNA is shown as dashed line and HPV18 DNA as solid line.…”

Adenovirus E1B55K Region Is Required To Enhance Cyclin E Expression for Efficient Viral DNA Replication

“…First, E1B55K-mutated viruses are highly impaired in their ability to produce viruses in HeLa cells (1,62), which contain and express the human papillomavirus E6 protein (43,76,77). The E6 protein, having a function of interfering with p53 (74,75), cannot compensate for E1B55K loss for virus replication in HeLa cells.…”

Detection of EBV, HBV, HCV, HIV-1, HTLV-I and -II, and SMRV in Human and Other Primate Cell Lines

“…Indeed, some cell lines are known to harbor human pathogenic viruses, among them the well-known and widely distributed HeLa cell line which contains the human papilloma virus integrated into its genome [4]. Besides the infection of the primary material which may be traced back to the donor, contaminations of cell cultures can also be introduced secondarily by laboratory personnel or from other infected cells when handled simultaneously.…”