title: EBNA promoter usage in EBV-negative Burkitt lymphoma cell lines converted with a neomycin-resistant EBV strain.
abstract: Latent Epstein-Barr virus (EBV) uses two alternative strategies to express the Epstein-Barr nuclear antigens (EBNAs). Resting normal B cells harboring latent virus and Burkitt's lymphoma (BL) cells use monocistronic messages generated from the Q promoter (restricted strategy). EBV-transformed immunoblasts express all EBNAs by using giant messages generated from the W/C promoter (full program). Whether the virus establishes the restricted program on primary infection of a BL cell (or its progenitor) or, alternatively, whether such cells are generated by phenotypic down-regulation from the immunoblast is unclear. We found previously that conversion of EBV-negative BL lines to EBV-positive sublines required repeated exposure to large virus doses. The converted sublines used the full program. However, the possibility that cells with a full program had a selective advantage during the long period of in vitro passage could not be excluded. We therefore infected EBV-negative BL lines with recombinant EBV carrying a neomycin resistance marker. Most convertants of the 12 lines tested were positive for YUK splicing, indicative of the full program, but some were also positive for the restricted QUK splice program. One convertant DG75 line showing both YUK and QUK was cloned and gave rise to stable QUK users. We conclude that EBV infection of established BL lines can give rise to subclones with either the full or the restricted program. The fact that all EBVs carrying BL lines use the restricted program in vitro may be a consequence of immunoselection.
authors.affiliation: Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden. akimae@eos.ocn.ne.jp
authors.forename: A
authors.initials: A
authors.lastname: Maeda
authors.forename: C
authors.initials: C
authors.lastname: Kiss
authors.forename: F
authors.initials: F
authors.lastname: Chen
authors.forename: B
authors.initials: B
authors.lastname: Ehlin-Henriksson
authors.forename: N
authors.initials: N
authors.lastname: Nagy
authors.forename: L
authors.initials: L
authors.lastname: Szekely
authors.forename: K
authors.initials: K
authors.lastname: Takada
authors.forename: E
authors.initials: E
authors.lastname: Klein
authors.forename: G
authors.initials: G
authors.lastname: Klein
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002051:Burkitt Lymphoma / Q000235:genetics / Q000473:pathology*; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral / Q000235:genetics*; D004352:Drug Resistance, Microbial; D019309:Epstein-Barr Virus Nuclear Antigens / Q000032:analysis / Q000235:genetics*; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D004854:Herpesvirus 4, Human / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D009355:Neomycin / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000502:physiology*; D014407:Tumor Cells, Cultured; D014763:Viral Matrix Proteins / Q000032:analysis; D014764:Viral Proteins
chemical_list: D000900:Anti-Bacterial Agents; C402641:EBNA-2 protein, Human herpesvirus 4; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D019309:Epstein-Barr Virus Nuclear Antigens; D014763:Viral Matrix Proteins; D014764:Viral Proteins; D009355:Neomycin; C417029:EBV-encoded nuclear antigen 1