Elevated expression of c-myc in lymphoblastoid cells does not support an Epstein-Barr virus latency III-to-I switch.
Epstein-Barr virus (EBV) transforms primary B cells in vitro. Established cell lines adopt a lymphoblastoid phenotype (LCL). In contrast, EBV-positive Burkitt's lymphoma (BL) cells, in which the proto-oncogene c-myc is constitutively activated, do not express a lymphoblastoid phenotype in vivo. The two different phenotypes are paralleled by two distinct programmes of EBV latent gene expression termed latency type I in BL cells and type III in LCL. Human B cell lines were established from a conditional LCL (EREB2-5) by overexpression of c-myc and inactivation of EBV nuclear protein 2 (EBNA2). These cells (A1 and P493-6) adopted a BL phenotype in the absence of EBNA2. However, the EBV latency I promoter Qp was not activated. Instead, the latency III promoter Cp remained active. These data suggest that the induction of a BL phenotype by overexpression of c-myc in an LCL is not necessarily paralleled by an EBV latency III-to-I switch.
Pajic
Alexander
A
GSF-Forschungszentrum für Umwelt und Gesundheit, Institut für Klinische Molekularbiologie und Tumorgenetik, Marchioninistr. 25, D-81377 München, Germany1.
Polack
Axel
A
GSF-Forschungszentrum für Umwelt und Gesundheit, Institut für Klinische Molekularbiologie und Tumorgenetik, Marchioninistr. 25, D-81377 München, Germany1.
Staege
Martin S
MS
GSF-Forschungszentrum für Umwelt und Gesundheit, Institut für Klinische Molekularbiologie und Tumorgenetik, Marchioninistr. 25, D-81377 München, Germany1.
Spitkovsky
Dimitry
D
Deutsches Krebsforschungszentrum (DKFZ), Forschungsschwerpunkt Angewandte Tumorvirologie, D-69120 Heidelberg, Germany2.
Baier
Barbara
B
GSF-Forschungszentrum für Umwelt und Gesundheit, Institut für Klinische Molekularbiologie und Tumorgenetik, Marchioninistr. 25, D-81377 München, Germany1.
Bornkamm
Georg W
GW
GSF-Forschungszentrum für Umwelt und Gesundheit, Institut für Klinische Molekularbiologie und Tumorgenetik, Marchioninistr. 25, D-81377 München, Germany1.
Laux
Gerhard
G
GSF-Forschungszentrum für Umwelt und Gesundheit, Institut für Klinische Molekularbiologie und Tumorgenetik, Marchioninistr. 25, D-81377 München, Germany1.
D001402:B-Lymphocytes / Q000378:metabolism / Q000821:virology*; D002051:Burkitt Lymphoma / Q000821:virology*; D002461:Cell Line, Transformed; D019309:Epstein-Barr Virus Nuclear Antigens / Q000378:metabolism; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000502:physiology*; D006801:Humans; D011401:Promoter Regions, Genetic; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D017735:Virus Latency / Q000235:genetics
D019309:Epstein-Barr Virus Nuclear Antigens; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger