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bioRxiv · 10.1101/2021.02.26.433008

The Epstein-Barr virus ubiquitin deconjugase BPLF1 regulates the activity of Topoisomerase II during virus replication

Li, J.·Nagy, N.·Liu, J.·Gupta, S.·Frisan, T.·Hennig, T.·Cameron, D. P.·Baranello, L.·Masucci, M. G.
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Abstract

Topoisomerases are essential for the replication of herpesviruses but the mechanisms by which the viruses hijack the cellular enzymes are largely unknown. We found that topoisomerase-II (TOP2) is a substrate of the Epstein-Barr virus (EBV) ubiquitin deconjugase BPLF1. BPLF1 selectively inhibited the ubiquitination of TOP2 following treatment with topoisomerase poisons, interacted with TOP2 and TOP2{beta} in co-immunoprecipitation and in vitro pull-down, stabilized Etoposide-trapped TOP2 cleavage complexes (TOP2cc) and promoted TOP2 SUMOylation, which halted the DNA-damage response and reduced Etoposide toxicity. Induction of the productive virus cycle promoted the accumulation of TOP2{beta}cc, enhanced TOP2{beta} SUMOylation, and reduced Etoposide toxicity in lymphoblastoid cell lines carrying recombinant EBV encoding the active enzyme. Attenuation of this phenotype upon expression of a catalytic mutant BPLF1-C61A impaired viral DNA synthesis and virus release. These findings highlight a previously unrecognized function of BPLF1 in promoting non-proteolytic pathways for TOP2cc debulking that favor cell survival and virus production.

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Li, J., Nagy, N., Liu, J., Gupta, S., Frisan, T., Hennig, T., Cameron, D. P., Baranello, L., Masucci, M. G.. 2021-02-27. The Epstein-Barr virus ubiquitin deconjugase BPLF1 regulates the activity of Topoisomerase II during virus replication. https://doi.org/10.1101/2021.02.26.433008

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