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Message: <blockquote data-quote="Shemeska" data-source="post: 2735803" data-attributes="member: 11697">Here's the abstract:STEWART, TODD WESLEY, M.S.  Studies of Epstein-Barr Virus BZLF1 Protein Binding to Human Mitotic Chromosomes. (2005)Directed by Dr. Amy L. Adamson. 71 pp.    The Epstein-Barr virus (EBV) immediate-early proteins BZLF1 (Z) and BRLF1 (R) together act as transcription factors to activate the promoters of the EBV early genes. Z has been observed to associate with the mitotic chromosomes during cellular division, and I found that this localization pattern is not unique to HeLa cells, but appears in D98HER1, NIH3T3, and Daudi cell lines, but not in Ramos cells. The localization of Z on the mitotic chromosomes within these cell lines, with the sole exception of Ramos cells, does not seem to depend on cell type / morphology or on EBV infection status of the cells. Additionally I examined if the presence of Z and R have any effect on each other’s localization and expression when co-transfected into a cell. In this case I found that while when R is expressed singly, it does not localize to the mitotic chromosomes, but that when expressed along with Z, both R and Z localized on the mitotic chromosomes.Z is also known to associate with a number of host proteins, such as p53 that it binds to and inactivates, as well as Pax5. These interactions potentially modify the host environment to promote survival and long-term proliferation of EBV, the inactivation of p53 likely preventing p53-mediated apoptosis during lytic phase replication of the EBV infected host cell. While we had previously observed that Z localizes to the mitotic chromosomes in some cases, it had also been observed that Z alters the localization of some of the proteins that it is known to interact with. In these cases, Z appears to recruit them to the mitotic chromosomes in a pattern very different from their normal localization. I examined a series of these Z-interacting host proteins both singly and in conjunction with transfected and expressed Z to determine if Z modifies their cellular localization. I found a partially altered localization for CREB and p65, in which they were present on the mitotic chromosomes, though not to the same degree as Z, and no change in localization for CBP, p53, and Pax-5.     In contrast to the mitotic chromosome localization of Z in HeLa cells, a different pattern has been observed with a mutant form known as Z311. This mutant protein, which is unable to bind to DNA, does not localize to chromosomes. Rather, the protein is localized to discrete “Z311 bodies” within the nucleus that appear both smaller and separate from promyelocytic leukemia (PML) bodies. I found that Z311 bodies were found only in EBV negative cells, regardless of cell type. However, the appearance of Z311 bodies in other cell types was not as distinct as preliminary work (unpublished) in our lab initially seemed to indicate.    I also examined the expression and localization (in HeLa cells) of other Z mutant proteins that were capable of DNA binding. All of these mutant forms of Z localized to mitotic chromosomes in a pattern similar to wild type Z. Together, these results indicate that the DNA-binding domain of Z is necessary and sufficient for localization to the mitotic chromosomes.</blockquote>

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