The HPV E2 protein targets several cellular proteins during DNA replication and mitosis to facilitate viral DNA replication and persistence. Work is on-going to characterise these virus-host interactions and decipher their importance in the HPV life cycle.
Characterisation of the functional interactions facilitated by the HPV E2 proteins that are required for viral persistence.
Work in the Parish laboratory is primarily focused on how HPV genomes are passed to daughter cells during mitotic division. To ensure the passage of viral genomes to new cells, papillomaviruses hijack some of the mechanisms that exist in host cells required the maintenance of genome stability. In particular, the HPV E2 protein targets several cellular proteins during DNA replication and mitosis to facilitate attachment of genomes to mitotic chromosomes (Figure 1). Work is on going to characterise these virus-host interactions and the cellular pathways hijacked by HPV and decipher their importance in the HPV life cycle. This project is funded by the Royal Society.
Right: Mechanism of viral genome tethering during mitosis. Many episomally maintained DNA viruses tether genomes to host cell chromosomes during mitosis. In general, a virally encoded DNA-binding protein (red; here shown as HPV E2) associates simultaneously with the viral genome (circle) and host cell chromatin (blue) or chromatin-bound cellular protein(s) (green).
Functional analysis of the ChlR1 DNA helicase in HPV and host cell DNA replication.
Work is on-going in the Parish lab to characterise to function of the ChlR1 DNA helicase in host cell DNA replication. Using a variety of methods including the DNA fibre technique, immunofluorescent microscopy, cell cycle analysis and sister chromatid cohesion analysis, we are able to study the function of this DNA helicase in the maintenance of host cell genome stability.
We are also interested in how ChlR1 facilitates the persistence of HPV episomes. Using FRET analysis we have shown that E2 directly targets ChlR1 during DNA replication. This has lead us to propose the model shown in figure 2. This work is funded by Medical Research Scotland and The Royal Society.
Above: Targeting of ChlR1 by HPV E2 during DNA replication to ensure viral persistence.(A) Cellular DNA replication fork movement from left to right. (B) Replication pauses as a cohesin ring is encountered promoting recruitment of ChlR1, E2 and viral DNA. (C) ChlR1 promotes re-initiation of DNA replication and leaves the complex. HPV E2 and viral DNA stay bound to the chromatin.
Characterisation of DNA binding proteins recruited to the HPV genome to control viral gene expression.
Using chromatin immunoprecipitation approaches we have identified several novel host cell proteins that are recruited to HPV genomes. We are currently characterising these interactions and their importance in the control of viral gene expression and/or replication. This project is funded Cancer Research UK and Tenovus Scotland.
The study of novel interactions between the HPV E2 and host cell proteins that alter sub cellular vesicle trafficking within infected cells.
We have recently identified a novel binding partner of E2 that is important in the regulation of sub-cellular trafficking. Preliminary studies suggest that E2 alters the function of the protein and therefore alters vesicle trafficking within infected cells. We are currently characterising this interaction and its role in the completion of the HPV life cycle.