Mapping EBNA-1 domains involved in binding to metaphase chromosomes.
The Epstein-Barr virus (EBV) genome can persist in dividing human B cells as multicopy circular episomes. Viral episomes replicate in synchrony with host cell DNA and are maintained at a relatively constant copy number for a long time. Only two viral elements, the replication origin OriP and the EBNA-1 protein, are required for the persistence of viral genomes during latency. EBNA-1 activates OriP during the S phase and may also contribute to the partition and/or retention of viral genomes during mitosis. Indeed, EBNA-1 has been shown to interact with mitotic chromatin. Moreover, viral genomes are noncovalently associated with metaphase chromosomes. This suggests that EBNA-1 may facilitate the anchorage of viral genomes on cellular chromosomes, thus ensuring proper partition and retention. In the present paper, we have investigated the chromosome-binding activity of EBV EBNA-1, herpesvirus papio (HVP) EBNA-1, and various derivatives of EBV EBNA-1, fused to a variant of the green fluorescent protein. The results show that binding to metaphase chromosomes is a common property of EBV and HVP EBNA-1. Further studies indicated that at least three independent domains (CBS-1, -2, and -3) mediate EBNA-1 binding to metaphase chromosomes. In agreement with the anchorage model, two of these domains mapped to a region that has been previously demonstrated to be required for the long-term persistence of OriP-containing plasmids.
Marechal
V
V
Service de Microbiologie, Hôpital Rothschild, 75571 Paris Cedex 12, France. vmarecha@infobiogen.fr
Dehee
A
A
Chikhi-Brachet
R
R
Piolot
T
T
Coppey-Moisan
M
M
Nicolas
J C
JC
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002874:Chromosome Mapping; D002877:Chromosomes, Human; D019309:Epstein-Barr Virus Nuclear Antigens / Q000235:genetics* / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008677:Metaphase; D008969:Molecular Sequence Data; D010215:Papio; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D019309:Epstein-Barr Virus Nuclear Antigens; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins