title: Requirement of replication licensing for the dyad symmetry element-dependent replication of the Epstein-Barr virus oriP minichromosome.
abstract: Latent Epstein-Barr virus genome is maintained in cells by the viral oriP-binding factor EBNA1 and cellular replication factors. EBNA1 binds to the dyad symmetry (DS) element in oriP and initiates DNA replication once in a single S phase, but the mechanism by which this DS-dependent replication is initiated is unknown. Replication licensing of cellular chromatins occurs during early G1 phase. Because licensing is essential for the next round of replication in S phase, it facilitates once-in-a-cell-cycle replication of the cellular genome. Using the transient replication assay with HeLa/EB1 cell, we demonstrate that the oriP plasmid required a cell cycle window including early G1 phase for replication in the next S phase. The plasmid containing only the DS element had a similar requirement of early G1 phase for replication. Analysis using sucrose density gradient centrifugation revealed that the oriP minichromosome existed in two distinct states: one formed at late G1 and the other formed at G2/M. These results suggest that the DS-dependent DNA replication from oriP requires the replication licensing, implying a possible involvement of the cellular licensing factor MCM in the DNA replication from oriP.
authors.affiliation: Division of Virology and Immunology, Medical Research Institute, Tokyo Medical and Dental University, Yushima 1-5-45, Tokyo, Bunkyo, 113-8510, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Shirakata
authors.forename: K I
authors.initials: KI
authors.lastname: Imadome
authors.forename: K
authors.initials: K
authors.lastname: Hirai
mesh_terms: D002453:Cell Cycle; D002499:Centrifugation, Density Gradient; D004261:DNA Replication; D019309:Epstein-Barr Virus Nuclear Antigens; D015967:Gene Expression Regulation, Viral; D006367:HeLa Cells; D004854:Herpesvirus 4, Human / Q000235:genetics* / Q000502:physiology*; D006801:Humans; D010957:Plasmids / Q000235:genetics; D018741:Replication Origin; D016196:S Phase; D014162:Transfection; D014407:Tumor Cells, Cultured; D014779:Virus Replication
chemical_list: D019309:Epstein-Barr Virus Nuclear Antigens