ABSTRACT: Epstein-Barr Virus Nuclear Antigen 2 (EBNA2) gene regulation through the cell RBPJ transcription factor (TF) is essential for conversion of resting B-lymphocytes (RBLs) into Lymphoblastoid Cell Lines (LCLs). ChIP-seq investigation of EBNA2 and RBPJ sites in LCL DNA found EBNA2 at 5151 and RBPJ at 10,529 sites. EBNA2 was 72% localized with RBPJ, predominantly at intergenic and intronic sites and only 14% at promoter sites. EBNA2/RBPJ sites were enriched for Early B-cell Factor (EBF, 60%), RUNX(41%), ETS(35%), NF-ï«B(31%), and PU.1(17%) TF motifs. Using ENCyclopedia Of DNA Elements (ENCODE) LCL data, EBF, RELA, and PU.1 were found at 54%, 31%, and 17% of EBNA2 sites. K-Means clustering of EBNA2 site associated TFs found RELA-ETS, EBF-RUNX, EBF, ETS, RBPJ, and repressive RUNX ranked highest to lowest in nearly symmetric H3K4me1 signal distribution and nucleosome depletion, marks of active chromatin. Although quantitatively less, high level nearly symmetric H3K4me1 signals with nucleosome depletion at the same sites in RBLs was remarkably similar to LCLs, indicating that EBNA2 localizes into a pre-established RBL chromatin pattern, which likely evolved to enable RBL antigen-induced proliferation. EBF was critical for EBNA2 activation of the EBV LMP1 promoter. LCL HiC data mapped intergenic EBNA2 sites to EBNA2 up-regulated genes. Fluorescence In Situ Hybridization (FISH), conditional EBNA2 FISH, Chromatin Conformation Capture (3C), and 3C q-PCR, linked EBNA2/RBPJ enhancers 428 kb 5' of MYC to MYC. These data support the hypothesis that EBNA2 evolved to exploit the RBL transcription framework to drive B-lymphocyte proliferation in primary human infection.
