Dataset Information

E2F1 mediated apoptosis induced by the DNA damage response is blocked by EBV nuclear antigen 3C in lymphoblastoid cells.

ABSTRACT: EBV latent antigen EBNA3C is indispensible for in vitro B-cell immortalization resulting in continuously proliferating lymphoblastoid cell lines (LCLs). EBNA3C was previously shown to target pRb for ubiquitin-proteasome mediated degradation, which facilitates G1 to S transition controlled by the major transcriptional activator E2F1. E2F1 also plays a pivotal role in regulating DNA damage induced apoptosis through both p53-dependent and -independent pathways. In this study, we demonstrate that in response to DNA damage LCLs knocked down for EBNA3C undergo a drastic induction of apoptosis, as a possible consequence of both p53- and E2F1-mediated activities. Importantly, EBNA3C was previously shown to suppress p53-induced apoptosis. Now, we also show that EBNA3C efficiently blocks E2F1-mediated apoptosis, as well as its anti-proliferative effects in a p53-independent manner, in response to DNA damage. The N- and C-terminal domains of EBNA3C form a stable pRb independent complex with the N-terminal DNA-binding region of E2F1 responsible for inducing apoptosis. Mechanistically, we show that EBNA3C represses E2F1 transcriptional activity via blocking its DNA-binding activity at the responsive promoters of p73 and Apaf-1 apoptosis induced genes, and also facilitates E2F1 degradation in an ubiquitin-proteasome dependent fashion. Moreover, in response to DNA damage, E2F1 knockdown LCLs exhibited a significant reduction in apoptosis with higher cell-viability. In the presence of normal mitogenic stimuli the growth rate of LCLs knockdown for E2F1 was markedly impaired; indicating that E2F1 plays a dual role in EBV positive cells and that active engagement of the EBNA3C-E2F1 complex is crucial for inhibition of DNA damage induced E2F1-mediated apoptosis. This study offers novel insights into our current understanding of EBV biology and enhances the potential for development of effective therapies against EBV associated B-cell lymphomas.

SUBMITTER: Saha A

PROVIDER: S-EPMC3305458 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

E2F1 mediated apoptosis induced by the DNA damage response is blocked by EBV nuclear antigen 3C in lymphoblastoid cells.

Saha Abhik A Lu Jie J Morizur Lise L Upadhyay Santosh K SK Aj Mahadesh Prasad MP Robertson Erle S ES

PLoS pathogens 20120315 3

EBV latent antigen EBNA3C is indispensible for in vitro B-cell immortalization resulting in continuously proliferating lymphoblastoid cell lines (LCLs). EBNA3C was previously shown to target pRb for ubiquitin-proteasome mediated degradation, which facilitates G1 to S transition controlled by the major transcriptional activator E2F1. E2F1 also plays a pivotal role in regulating DNA damage induced apoptosis through both p53-dependent and -independent pathways. In this study, we demonstrate that in ...[more]

PMID: 22438805

Similar Datasets

Project description:Epstein Barr virus (EBV) nuclear antigen 3C (EBNA3C) is an essential transcription factor for initiating and maintaining human B lymphocyte transformation to lymphoblastoid cell lines (LCLs). To comprehensively identify EBNA3C regulated cell genes in LCLs, oligonucleotide arrays were used to compare RNA abundances in 3 different LCLs transformed by an EBV that conditionally expresses EBNA3C. Cell RNA levels were assessed in actively growing LCLs, under non-permissive or permissive conditions or under non-permissive conditions after transcomplementation with wild type EBNA3C. A two-way ANOVA model with covariates including the 3 different clone effects and the 3 EBNA3C expression levels, identified 550 EBNA3C regulated genes, with False Discovery Rate <0.01 and >1.5 fold change. A seeded Bayesian network analysis of the 80 most significantly EBNA3C regulated genes that changed >1.5 fold, positioned RAC1, LYN and TNF upstream of other EBNA3C regulated genes. Further, Gene Set Enrichment Assay (GSEA) identified EBNA3C regulated genes to be enriched for MAP kinase signaling, cytokine-cytokine receptor interactions, JAK-STAT signaling, and cell adhesion molecule effects, implicating these pathways in LCL growth or survival. Moreover, 106 EBNA3C regulated genes could be placed in protein interaction networks. Since CXCL12 and CXCR4 signaling are implicated in LCL growth and were EBNA3C up-regulated, up-regulation of CXCL12 was validated by qRT-PCR and effects on induced LCL migration were confirmed. EBNA3C regulated genes significantly overlapped with EBNA2 and EBNA3A regulated genes, consistent with a central role for RBP/CSL in these effects. RNAs from three different Lymphoblastoid Cell Lines(LCLs) expressing conditional EBNA3C grown under permissive or non-permissive conditions for 7 days; the same LCLs transcompletemented with EBNA3C expressed in trans at full wild-type level were used to identify EBNA3C regualted cellular genes. Total cell RNAs were hybrdized to Affymetrix U-133 Plus 2.0 microarrays. A two way ANOVA model was developed with covariates including the 3 different clone effects and the 3 EBNA3C expression levels and identified 550 EBNA3C regulated genes.

Dataset Information

E2F1 mediated apoptosis induced by the DNA damage response is blocked by EBV nuclear antigen 3C in lymphoblastoid cells.

Publications

E2F1 mediated apoptosis induced by the DNA damage response is blocked by EBV nuclear antigen 3C in lymphoblastoid cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets