PT  - JOURNAL ARTICLE
AU  - Maier, Sabine
AU  - Santak, Maja
AU  - Mantik, Anja
AU  - Grabusic, Kristina
AU  - Kremmer, Elisabeth
AU  - Hammerschmidt, Wolfgang
AU  - Kempkes, Bettina
TI  - A Somatic Knockout of CBF1 in a Human B-Cell Line Reveals that Induction of CD21 and CCR7 by EBNA-2 Is Strictly CBF1 Dependent and that Downregulation of Immunoglobulin M Is Partially CBF1 Independent
AID  - 10.1128/JVI.79.14.8784-8792.2005
DP  - 2005 Jul 01
TA  - Journal of Virology
PG  - 8784--8792
VI  - 79
IP  - 14
4099  - http://jvi.asm.org/content/79/14/8784.short
4100  - http://jvi.asm.org/content/79/14/8784.full
SO  - J. Virol.2005 Jul 01; 79
AB  - CBF1 is a cellular highly conserved DNA binding factor that is ubiquitously expressed in all tissues and acts as a repressor of cellular genes. In Epstein-Barr virus growth-transformed B-cell lines, CBF1 serves as a central DNA adaptor molecule for several viral proteins, including the viral transactivator Epstein-Barr virus nuclear antigen 2 (EBNA-2). EBNA-2 binds to CBF1 and thereby gains access to regulatory regions of target genes and activates transcription. We have inactivated the CBF1 gene by homologous recombination in the human B-cell line DG75 and characterized changes in cellular gene expression patterns upon loss of CBF1 and activation of EBNA-2. CBF1-negative DG75 cells were viable and proliferated at wild-type rates. Loss of CBF1 was not sufficient to release repression of the previously described EBNA-2 target genes CD21 or CCR7, whereas induction of both target genes by EBNA-2 required CBF1. In contrast, repression of immunoglobulin M by EBNA-2 was mainly CBF1 independent. CBF1-negative DG75 B cells thus provide an excellent tool to dissect CBF1-dependent and -independent functions exerted by the EBNA-2 protein in future studies.