title: Regulation of c-fgr proto-oncogene expression in Burkitt's lymphoma cells: effect of interferon treatment and relationship to EBV status and c-myc mRNA levels.
abstract: The proto-oncogene c-fgr is expressed in transformed human B lymphoid cell lines and has been reported to be induced in cells infected with the Epstein-Barr virus (EBV). We have compared the levels of c-fgr mRNA in several B cell lines and have examined the effects of interferon-induced changes in growth rate of Daudi cells on the concentration of this mRNA. High levels were found in exponentially growing EBV-positive Raji and Daudi cells but the amounts in B95-8 and P3HR-1 cells (also EBV-positive) were lower than in the EBV-negative cell line Ramos. Growth inhibition of Daudi cells by interferon-alpha is preceded by a reduction in c-fgr expression, with a 56% decrease observed within 6 h. The differences in the amounts of c-fgr mRNA in the various cell lines and in control versus interferon-treated cells are similar to the differences in the c-myc mRNA contents of these cells. These results indicate that c-fgr expression bears little relationship to the EBV status of B lymphoid cell lines but may play a role, in conjunction with c-myc expression, in growth regulation by interferons. Other conditions which influence Daudi cell proliferation, such as treatment with a phorbol ester or growth to high cell density, also inhibit c-fgr expression but to a lesser extent than interferon treatment.
authors.affiliation: Department of Cellular and Molecular Sciences, St George's Hospital Medical School, London, UK.
authors.forename: N A
authors.initials: NA
authors.lastname: Sharp
authors.forename: M J
authors.initials: MJ
authors.lastname: Luscombe
authors.forename: M J
authors.initials: MJ
authors.lastname: Clemens
mesh_terms: D015152:Blotting, Northern; D002051:Burkitt Lymphoma / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects; D004854:Herpesvirus 4, Human / Q000032:analysis; D006801:Humans; D066298:In Vitro Techniques; D007370:Interferon Type I / Q000494:pharmacology*; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D011994:Recombinant Proteins; D013997:Time Factors; D014407:Tumor Cells, Cultured; D019061:src-Family Kinases
chemical_list: D007370:Interferon Type I; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011994:Recombinant Proteins; C053102:proto-oncogene proteins c-fgr; D019061:src-Family Kinases