title: Interaction of Marek's disease virus oncoprotein Meq with heat-shock protein 70 in lymphoid tumour cells.
abstract: Marek's disease virus (MDV) is a highly oncogenic alphaherpesvirus that induces the rapid onset of T-cell lymphomas in poultry. The MDV-encoded oncoprotein Meq plays an important role in oncogenicity, as its deletion abolishes the ability of the virus to induce tumours. It has been shown previously that Meq oncogenicity is linked to its interaction with C-terminal binding protein 1 (CtBP), a property also shared by other virus-encoded oncoproteins such as adenovirus E1A and Epstein-Barr virus EBNA3A and -3C. Therefore, this study examined whether Meq also shares the properties of these viral oncoproteins in interacting with other binding partners such as heat-shock protein 70 (Hsp70), a molecular chaperone protein linked to multiple cellular functions including neoplastic transformation. Confocal microscopic analysis demonstrated that MDV infection induced nuclear accumulation of Hsp70 and its co-localization with Meq. Biochemical evidence of Meq-Hsp70 interaction was obtained by two-way immunoprecipitation with Meq- and Hsp70-specific antibodies. To demonstrate further the Meq-Hsp70 interaction in virus-induced lymphomas, recombinant MDV was generated expressing an N-terminal tandem affinity purification (TAP) tag-fused Meq by mutagenesis of the infectious BAC clone of the oncogenic MDV strain RB-1B. Demonstration of Hsp70 in the TAP-tag affinity purified Meq from tumours induced by the recombinant virus, using quadrupole time-of-flight tandem mass spectrometry analysis, further confirmed the Meq-Hsp70 interaction in the transformed lymphocytes. Given the well-documented evidence of the tumorigenic properties of Hsp70 and its interaction with a number of other known viral oncoproteins, demonstration of the interaction of Meq and Hsp70 is significant in MDV oncogenesis.
authors.affiliation: Viral Oncogenesis Group, Institute for Animal Health, Compton RG20 7NN, UK.
authors.forename: Yuguang
authors.initials: Y
authors.lastname: Zhao
authors.forename: Dominic
authors.initials: D
authors.lastname: Kurian
authors.forename: Hongtao
authors.initials: H
authors.lastname: Xu
authors.forename: Lawrence
authors.initials: L
authors.lastname: Petherbridge
authors.forename: Lorraine P
authors.initials: LP
authors.lastname: Smith
authors.forename: Lawrence
authors.initials: L
authors.lastname: Hunt
authors.forename: Venugopal
authors.initials: V
authors.lastname: Nair
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002642:Chick Embryo; D004195:Disease Models, Animal; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D008381:Herpesvirus 2, Gallid / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008223:Lymphoma / Q000378:metabolism* / Q000821:virology; D008380:Marek Disease / Q000378:metabolism* / Q000821:virology; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D013047:Specific Pathogen-Free Organisms
chemical_list: C100369:Eco-Q protein, Gallid herpesvirus 2; D018840:HSP70 Heat-Shock Proteins; D009856:Oncogene Proteins, Viral