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Abstract
In papillomavirus infections, the viral genome is established as a double-stranded DNA episome. To segregate the episomes into daughter cells during mitosis, they are tethered to cellular chromatin by the viral E2 protein. We previously demonstrated that the E2 proteins of diverse papillomavirus types, including bovine papillomavirus (BPV) and human papillomavirus 16 (HPV16), associate with the cellular DNA helicase ChlR1. This virus-host interaction is important for the tethering of BPV E2 to mitotic chromatin and the stable maintenance of BPV episomes. The role of the association between E2 and ChlR1 in the HPV16 life cycle is unresolved. Here we show that an HPV16 E2 Y131A mutant (E2Y131A) had significantly reduced binding to ChlR1 but retained transcriptional activation and viral origin-dependent replication functions. Subcellular fractionation of keratinocytes expressing E2Y131A showed a marked change in the localization of the protein. Compared to that of wild-type E2 (E2WT), the chromatin-bound pool of E2Y131A was decreased, concomitant with an increase in nuclear matrix-associated protein. Cell cycle synchronization indicated that the shift in subcellular localization of E2Y131A occurred in mid-S phase. A similar alteration between the subcellular pools of the E2WT protein occurred upon ChlR1 silencing. Notably, in an HPV16 life cycle model in primary human keratinocytes, mutant E2Y131A genomes were established as episomes, but at a markedly lower copy number than that of wild-type HPV16 genomes, and they were not maintained upon cell passage. Our studies indicate that ChlR1 is an important regulator of the chromatin association of E2 and of the establishment and maintenance of HPV16 episomes.
Original language | English |
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Article number | e01853-16 |
Number of pages | 16 |
Journal | Journal of virology |
Volume | 91 |
Issue number | 1 |
Early online date | 19 Oct 2016 |
DOIs | |
Publication status | Published - Jan 2017 |
Bibliographical note
Acknowledgments:We thank Joseph Spitzer and his patients for the collection and donation of foreskin tissue.
This work was supported by a Royal Society University Research Fellowship awarded to J.L.P. (grant UF110010). L.H. and L.M.-M. were funded by studentships awarded to J.L.P. by the Universities of St. Andrews and Birmingham. K.C.-L. is funded by a Medical Research Council project grant awarded to J.L.P. and S.R. (grant MR/N023498/1).
We have no conflicts of interest to declare.
Keywords
- DNA helicase
- episome
- papillomavirus
- persistence
- virus-hostinteraction
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Dive into the research topics of 'The cellular DNA helicase ChlR1 regulates chromatin and nuclear matrix attachment of the human papillomavirus type 16 E2 protein and high copy viral genome establishment: ChlR1 regulates the chromatin association of HPV16 E2'. Together they form a unique fingerprint.Projects
- 2 Finished
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Understanding the role of the chromatin insulator CTCF in human papillomavirus gene expression and disease progression
Parish, J. & Roberts, S.
1/07/16 → 31/03/20
Project: Research Councils
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The Functional Role of ChIR1 in Genome Integrity and Papillomavirus Persistence
1/02/13 → 31/01/16
Project: Research Councils