The DNA segregation mechanism of Epstein-Barr virus nuclear antigen 1.
Latent Epstein-Barr virus (EBV) genomes are maintained in human cells as low copy number episomes that are thought to be partitioned by attachment to the cellular mitotic chromosomes through the viral EBNA1 protein. We have identified a human protein, EBP2, which interacts with the EBNA1 sequences that govern EBV partitioning. Here we show that, in mitosis, EBP2 localizes to the condensed cellular chromosomes producing a staining pattern that is indistinguishable from that of EBNA1. The localization of EBNA1 proteins with mutations in the EBP2 binding region was also examined. An EBNA1 mutant (delta325-376) disrupted for EBP2 binding and segregation function was nuclear but failed to attach to the cellular chromosomes in mitosis. Our results indicate that amino acids 325-376 mediate the binding of EBNA1 to mitotic chromosomes and strongly suggest that EBNA1 mediates EBV segregation by attaching to EBP2 on the cellular mitotic chromosomes.
Department of Medical Genetics and Microbiology, University of Toronto, Ontario, Canada.
H
H
Wu
D F
DF
Ceccarelli
L
L
Frappier
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D001402:B-Lymphocytes / Q000502:physiology; D002051:Burkitt Lymphoma / Q000235:genetics; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002875:Chromosomes / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D003703:Demecolcine / Q000494:pharmacology; D019309:Epstein-Barr Virus Nuclear Antigens / Q000235:genetics* / Q000378:metabolism; D004854:Herpesvirus 4, Human / Q000502:physiology*; D006801:Humans; D008856:Microscopy, Fluorescence; D008938:Mitosis / Q000187:drug effects / Q000502:physiology; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins; D014407:Tumor Cells, Cultured
D000972:Antineoplastic Agents, Phytogenic; D002352:Carrier Proteins; C432687:EBNA1BP2 protein, human; D019309:Epstein-Barr Virus Nuclear Antigens; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D004247:DNA; C417029:EBV-encoded nuclear antigen 1; D003703:Demecolcine