Cell Cycle-Dependent EBNA1-DNA Cross-Linking Promotes Replication Termination at oriP and Viral Episome Maintenance

• Published in: Cell Vol. 184; no. 3; pp. 643 - 654.e13
• Main Authors: Dheekollu, Jayaraju, Wiedmer, Andreas, Ayyanathan, Kasirajan, Deakyne, Julianna S., Messick, Troy E., Lieberman, Paul M.
• Format: Journal Article
• Language: English
• Published: 21.01.2021
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/j.cell.2020.12.022

Epstein-Barr virus (EBV) is an oncogenic human herpesvirus that persists as a multicopy episome in proliferating host cells. Episome maintenance is strictly dependent on EBNA1, a sequence-specific DNA binding protein with no known enzymatic activities. Here, we show that EBNA1 forms a cell cycle-dependent DNA cross-link with EBV origin of plasmid replication oriP . EBNA1 tyrosine 518 (Y518) is essential for cross-linking to oriP and functionally required for episome maintenance and generation of EBV transformed lymphoblastoid cell lines (LCLs). Mechanistically, Y518 is required for replication fork termination at oriP in vivo and for the formation of SDS-resistant complexes in vitro . EBNA1-DNA cross-linking corresponds to single-strand endonuclease activity specific to DNA structures enriched at replication-termination sites, such as 4-way junctions. Taken together, these findings reveal that EBNA1 forms tyrosine-dependent DNA-protein crosslinks and single stand cleavage at oriP required for replication termination and viral episome maintenance. Cell cycle dependent recombinase-like activity of EBNA1 is required for replication termination and viral episome maintenance of oncogenic Epstein-Barr Virus.