Kaposi’s sarcoma-associated herpesvirus (KSHV) is the causative agent of several human malignancies. Herpesviruses are known to modulate cellular pathways responsible for the recognition and repair of DNA lesions, collectively known as the DNA damage response (DDR). Here it is demonstrated that lytic reactivation of KSHV in B cells results in activation of the ATM and DNA-PK kinases that regulate the response to DNA double-strand breaks (DSBs). This DDR does not depend on amplification of viral DNA and results in phosphorylation of downstream proteins involved in DNA repair, cell cycle regulation and apoptosis. Specific inhibition of ATM activity attenuates KSHV replication while, in contrast, abrogation of DNA-PK activity enhances amplification of viral DNA. It is also shown here that cells containing lytic virus enter S phase which is required for efficient viral replication and robust activation of the DDR. In addition, immunofluorescence microscopy reveals that DNA damage sensing proteins such as MRE11 and Ku80 localise to sites of KSHV replication while other DSB repair proteins form foci in cellular DNA. Specific inhibition of MRE11 exonuclease activity in B cells restricts KSHV replication efficiency indicating that this DDR protein contributes positively to this phase of the viral lifecycle.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:720738 |
| Date | January 2017 |
| Creators | Hollingworth, Robert |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/7641/ |
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