Cargando…

Mechanism of Genomic Instability in Cells Infected with the High-Risk Human Papillomaviruses

In HPV–related cancers, the “high-risk” human papillomaviruses (HPVs) are frequently found integrated into the cellular genome. The integrated subgenomic HPV fragments express viral oncoproteins and carry an origin of DNA replication that is capable of initiating bidirectional DNA re-replication in...

Descripción completa

Detalles Bibliográficos
Autores principales: Kadaja, Meelis, Isok-Paas, Helen, Laos, Triin, Ustav, Ene, Ustav, Mart
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2666264/
https://www.ncbi.nlm.nih.gov/pubmed/19390600
http://dx.doi.org/10.1371/journal.ppat.1000397
_version_ 1782166039967039488
author Kadaja, Meelis
Isok-Paas, Helen
Laos, Triin
Ustav, Ene
Ustav, Mart
author_facet Kadaja, Meelis
Isok-Paas, Helen
Laos, Triin
Ustav, Ene
Ustav, Mart
author_sort Kadaja, Meelis
collection PubMed
description In HPV–related cancers, the “high-risk” human papillomaviruses (HPVs) are frequently found integrated into the cellular genome. The integrated subgenomic HPV fragments express viral oncoproteins and carry an origin of DNA replication that is capable of initiating bidirectional DNA re-replication in the presence of HPV replication proteins E1 and E2, which ultimately leads to rearrangements within the locus of the integrated viral DNA. The current study indicates that the E1- and E2-dependent DNA replication from the integrated HPV origin follows the “onion skin”–type replication mode and generates a heterogeneous population of replication intermediates. These include linear, branched, open circular, and supercoiled plasmids, as identified by two-dimensional neutral-neutral gel-electrophoresis. We used immunofluorescence analysis to show that the DNA repair/recombination centers are assembled at the sites of the integrated HPV replication. These centers recruit viral and cellular replication proteins, the MRE complex, Ku70/80, ATM, Chk2, and, to some extent, ATRIP and Chk1 (S317). In addition, the synthesis of histone γH2AX, which is a hallmark of DNA double strand breaks, is induced, and Chk2 is activated by phosphorylation in the HPV–replicating cells. These changes suggest that the integrated HPV replication intermediates are processed by the activated cellular DNA repair/recombination machinery, which results in cross-chromosomal translocations as detected by metaphase FISH. We also confirmed that the replicating HPV episomes that expressed the physiological levels of viral replication proteins could induce genomic instability in the cells with integrated HPV. We conclude that the HPV replication origin within the host chromosome is one of the key factors that triggers the development of HPV–associated cancers. It could be used as a starting point for the “onion skin”–type of DNA replication whenever the HPV plasmid exists in the same cell, which endangers the host genomic integrity during the initial integration and after the de novo infection.
format Text
id pubmed-2666264
institution National Center for Biotechnology Information
language English
publishDate 2009
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-26662642009-04-24 Mechanism of Genomic Instability in Cells Infected with the High-Risk Human Papillomaviruses Kadaja, Meelis Isok-Paas, Helen Laos, Triin Ustav, Ene Ustav, Mart PLoS Pathog Research Article In HPV–related cancers, the “high-risk” human papillomaviruses (HPVs) are frequently found integrated into the cellular genome. The integrated subgenomic HPV fragments express viral oncoproteins and carry an origin of DNA replication that is capable of initiating bidirectional DNA re-replication in the presence of HPV replication proteins E1 and E2, which ultimately leads to rearrangements within the locus of the integrated viral DNA. The current study indicates that the E1- and E2-dependent DNA replication from the integrated HPV origin follows the “onion skin”–type replication mode and generates a heterogeneous population of replication intermediates. These include linear, branched, open circular, and supercoiled plasmids, as identified by two-dimensional neutral-neutral gel-electrophoresis. We used immunofluorescence analysis to show that the DNA repair/recombination centers are assembled at the sites of the integrated HPV replication. These centers recruit viral and cellular replication proteins, the MRE complex, Ku70/80, ATM, Chk2, and, to some extent, ATRIP and Chk1 (S317). In addition, the synthesis of histone γH2AX, which is a hallmark of DNA double strand breaks, is induced, and Chk2 is activated by phosphorylation in the HPV–replicating cells. These changes suggest that the integrated HPV replication intermediates are processed by the activated cellular DNA repair/recombination machinery, which results in cross-chromosomal translocations as detected by metaphase FISH. We also confirmed that the replicating HPV episomes that expressed the physiological levels of viral replication proteins could induce genomic instability in the cells with integrated HPV. We conclude that the HPV replication origin within the host chromosome is one of the key factors that triggers the development of HPV–associated cancers. It could be used as a starting point for the “onion skin”–type of DNA replication whenever the HPV plasmid exists in the same cell, which endangers the host genomic integrity during the initial integration and after the de novo infection. Public Library of Science 2009-04-24 /pmc/articles/PMC2666264/ /pubmed/19390600 http://dx.doi.org/10.1371/journal.ppat.1000397 Text en Kadaja et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Kadaja, Meelis
Isok-Paas, Helen
Laos, Triin
Ustav, Ene
Ustav, Mart
Mechanism of Genomic Instability in Cells Infected with the High-Risk Human Papillomaviruses
title Mechanism of Genomic Instability in Cells Infected with the High-Risk Human Papillomaviruses
title_full Mechanism of Genomic Instability in Cells Infected with the High-Risk Human Papillomaviruses
title_fullStr Mechanism of Genomic Instability in Cells Infected with the High-Risk Human Papillomaviruses
title_full_unstemmed Mechanism of Genomic Instability in Cells Infected with the High-Risk Human Papillomaviruses
title_short Mechanism of Genomic Instability in Cells Infected with the High-Risk Human Papillomaviruses
title_sort mechanism of genomic instability in cells infected with the high-risk human papillomaviruses
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2666264/
https://www.ncbi.nlm.nih.gov/pubmed/19390600
http://dx.doi.org/10.1371/journal.ppat.1000397
work_keys_str_mv AT kadajameelis mechanismofgenomicinstabilityincellsinfectedwiththehighriskhumanpapillomaviruses
AT isokpaashelen mechanismofgenomicinstabilityincellsinfectedwiththehighriskhumanpapillomaviruses
AT laostriin mechanismofgenomicinstabilityincellsinfectedwiththehighriskhumanpapillomaviruses
AT ustavene mechanismofgenomicinstabilityincellsinfectedwiththehighriskhumanpapillomaviruses
AT ustavmart mechanismofgenomicinstabilityincellsinfectedwiththehighriskhumanpapillomaviruses