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

Harris, Leanne, McFarlane-Majeed, Laura, Campos-León, Karen, Roberts, Sally and Parish, Joanna L (2016) 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. Journal of Virology, 91 (1). ISSN 0022-538X

[img] PDF - Published Version
Available under License Creative Commons Attribution.

Download (2MB)

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.

Item Type: Article
Schools and Departments: School of Life Sciences > Biochemistry
Depositing User: Leanne Harris
Date Deposited: 23 Nov 2017 10:04
Last Modified: 23 Nov 2017 10:04
URI: http://sro.sussex.ac.uk/id/eprint/71507

View download statistics for this item

📧 Request an update