Down-regulation of BLIMP1? by the EBV oncogene, LMP-1, disrupts the plasma cell differentiation program and prevents viral replication in B cells: implications for the pathogenesis of EBV-associated B-cell lymphomas.

ABSTRACT: An important pathogenic event in Epstein-Barr virus (EBV)-associated lymphomas is the suppression of virus replication, which would otherwise lead to cell death. Because virus replication in B cells is intimately linked to their differentiation toward plasma cells, we asked whether the physiologic signals that drive normal B-cell differentiation are absent in EBV-transformed cells. We focused on BLIMP1?, a transcription factor that is required for plasma cell differentiation and that is inactivated in diffuse large B-cell lymphomas. We show that BLIMP1? expression is down-regulated after EBV infection of primary germinal center B cells and that the EBV oncogene, latent membrane protein-1 (LMP-1), is alone capable of inducing this down-regulation in these cells. Furthermore, the down-regulation of BLIMP1? by LMP-1 was accompanied by a partial disruption of the BLIMP1? transcriptional program, including the aberrant induction of MYC, the repression of which is required for terminal differentiation. Finally, we show that the ectopic expression of BLIMP1? in EBV-transformed cells can induce the viral lytic cycle. Our results suggest that LMP-1 expression in progenitor germinal center B cells could contribute to the pathogenesis of EBV-associated lymphomas by down-regulating BLIMP1?, in turn preventing plasma cell differentiation and induction of the viral lytic cycle.

SUBMITTER: Vrzalikova K 

PROVIDER: S-EPMC3293751 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature