EBNA1 mediates the stable segregation or partitioning of EBV genomes during cell division by tethering them to the cellular mitotic chromosomes. We have discovered an interaction between EBNA1 and a human mitotic chromosomal protein, that we named EBP2 (EBNA1 binding protein 2), and have shown that the ability to bind EBP2 correlates with the ability of EBNA1 to attach to human chromosomes and to segregate EBV plasmids. We have also shown that EBNA1 can stably segregate EBV plasmids through chromosome attachment in yeast cells and that the human EBP2 protein is required for this process. Using siRNA technology, we have shown that EBP2 is critical for EBNA1 attachment to human chromosomes in mitosis. Our studies are facilitated by the yeast-based segregation system, which enables us to use yeast genetic approaches to uncover proteins that regulate these events. We are presently studying how EBP2 attaches to mitotic chromosomes, how the EBNA1-EBP2 interaction is regulated and what other cellular proteins are involved in EBNA1-mediated segregation.

Stable segregation of EBV-based plasmids in yeast occurs in the presence of EBNA1 and human EBP2. Shown here in comparison to a positive control plasmid containing a centromere (CEN).
Publications:

Sivachandran, N., Thawe, N.N. and Frappier, L. 2011 Epstein-Barr Nuclear Antigen 1 Replication and Segregation Functions in Nasopharyngeal Carcinoma Cell Lines. J. Virol. 85, 10425-10430.

Welcker, M., Larimore, E.A., Frappier, L. and Clurman, B.E. 2011 Nucleolar Targeting of Fbw7 by EBNA1-Binding Protein 2 and Glycogen Synthase Kinase 3. Mol. Cell. Biol. 31(6):1214-24.

Nayyar, V., Shire, K and Frappier, L. Mitotic Chromosome Interactions of Epstein-Barr Nuclear Antigen 1 (EBNA1) and human EBNA1 binding protein 2 (EBP2). J. Cell Science. In press.

Shire,K., Kapoor, P., Jiang, K., Ng Thow Hing, M., Nguyen, T. and Frappier, L. 2006 Regulation of the EBNA1 Epstein-Barr virus protein by Serine Phosphorylation and Arginine Methylation. J. Virol. 80, 5261-5272.

Kapoor, P., Lavoie, B. and Frappier, L. 2005 EBP2 plays a key role in Epstein-Barr Virus mitotic segregation and is regulated by Aurora family kinases. Mol. Cell Biol. 25, 4934-4945.

Kapoor, P and Frappier, L. 2003. EBNA1 partitions Epstein-Barr virus plasmids in yeast by attaching to hEBP2 on mitotic chromosomes. J. Virol. 77, 6946-6956.

Wu, H., Kapoor, P. and Frappier, L. 2002 Separation of the DNA replication, segregation and transcriptional activation functions of Epstein-Barr nuclear antigen 1. J. Virol. 25, 2480-2490.

Kapoor, P., Shire, K. and Frappier, L. 2001 Reconstitution of Epstein-Barr virus-based plasmid partitioning in budding yeast. EMBO J. 20, 222-230.

Wu, H., Ceccarelli, D.F.J. and Frappier, L. 2000 The DNA segregation mechanism of the Epstein-Barr virus EBNA1 protein. EMBO Reports 1, 140-144.

Shire, K., Ceccarelli, D.F., Avolio-Hunter, T.M. and Frappier, L. 1999 EBP2, a human protein that interacts with sequences of the Epstein-Barr nuclear antigen 1 important for plasmid maintenance. J. Virol. 73, 2587-2595.