Epstein-Barr virus LMP2A interferes with global transcription factor regulation when expressed during B-lymphocyte development.
Epstein-Barr virus (EBV) is associated with the development of malignant lymphomas and lymphoproliferative disorders in immunocompromised individuals. The LMP2A protein of EBV is thought to play a central role in this process by allowing the virus to persist in latently infected B lymphocytes. We have demonstrated that LMP2A, when expressed in B cells of transgenic mice, allows normal B-cell developmental checkpoints to be bypassed. To identify cellular genes targeted by LMP2A that are involved in this process, we have utilized DNA microarrays to compare gene transcription in B cells from wild-type versus LMP2A transgenic mice. In B cells from LMP2A transgenic mice, we observed decreased expression of many genes associated with normal B-cell development as well as reduced levels of the transcription factors that regulate their expression. In particular, expression of the transcription factor E2A was down-regulated in bone marrow and splenic B cells. Furthermore, E2A activity was inhibited in these cells as determined by decreased DNA binding and reduced expression of its target genes, including the transcription factors early B-cell factor and Pax-5. Expression of two E2A inhibitors, Id2 and SCL, was up-regulated in splenic B cells expressing LMP2A, suggesting a possible mechanism for E2A inhibition. These results indicate that LMP2A deregulates transcription factor expression and activity in developing B cells, and this likely allows for a bypass of normal signaling events required for proper B-cell development. The ability of LMP2A to interfere with B-cell transcription factor regulation has important implications regarding its role in EBV latency.
Portis
Toni
T
Department of Microbiology and Immunology, Northwestern University, Chicago, Illinois 60611, USA.
Longnecker
Richard
R
D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000502:physiology; D015536:Down-Regulation; D005786:Gene Expression Regulation; D051379:Mice; D008822:Mice, Transgenic; D020411:Oligonucleotide Array Sequence Analysis; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000502:physiology; D014763:Viral Matrix Proteins / Q000502:physiology*
D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D014763:Viral Matrix Proteins; C037662:EBV-associated membrane antigen, Epstein-Barr virus; C407909:TCF3 protein, human