Homo sapiens
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PROVIDER: PRJNA133791 | ENA |
REPOSITORIES: ENA
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Project description:Survival of all B cells depends on signals from the B-cell receptor (BCR). In BCRnegative B cells the latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) replaces this survival signal and might play a role in the development of EBV-positive Hodgkin lymphomas and posttransplantation lymphoproliferative disease. In these BCR-negative cells LMP2A provides a ‘tonic’ signal similar to BCR’s constitutive expression in the absence of antigen in order to maintain activating signaling pathways common to both receptor molecules. In most latently EBV-infected B cells LMP2A and BCR are co-expressed but it is largely unclear what LMP2A contributes with respect to B-cell activation, proliferation and viral latency in these BCR-positive cells. A common model suggests that LMP2A maintains herpesviral latency by blocking BCR-mediated signals but how LMP2A could serve both antithetical ends in BCRnegative and BCR-positive cells is elusive. Our comparative analysis of BCR and LMP2A now indicates that LMP2A is a true BCR mimic that dominates BCR-operated signaling pathways in EBV-infected, BCR-positive cells to provide activation signals, support stable infections in vivo and allow exit from latency. These findings suggest that LMP2A co-opts the situation in anergic B cells, where continuous BCR signaling results in maintenance of the anergic state accompanied by unresponsiveness to acute BCR stimulation. The microarray experiment was used to compare effects of BCR and LMP2A on gene expression regulation. EBV's LMP2A and the human BCR activate similar cellular target genes; some genes are regulated solely by BCR or LMP2A, no gene is counter regulated A 12 chip study using cDNA from three separate 2525 LMP2A knockout LCL cultures and three separate 3696.10 LMP2A:mCD69 LCL cultures; each culture tested before and after 90 min stimulation of the BCR and LMP2A:mCD69, respectively.
2011-01-01 | E-GEOD-25434 | biostudies-arrayexpress
Project description:Survival of all B cells depends on signals from the B-cell receptor (BCR). In BCRnegative B cells the latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) replaces this survival signal and might play a role in the development of EBV-positive Hodgkin lymphomas and posttransplantation lymphoproliferative disease. In these BCR-negative cells LMP2A provides a ‘tonic’ signal similar to BCR’s constitutive expression in the absence of antigen in order to maintain activating signaling pathways common to both receptor molecules. In most latently EBV-infected B cells LMP2A and BCR are co-expressed but it is largely unclear what LMP2A contributes with respect to B-cell activation, proliferation and viral latency in these BCR-positive cells. A common model suggests that LMP2A maintains herpesviral latency by blocking BCR-mediated signals but how LMP2A could serve both antithetical ends in BCRnegative and BCR-positive cells is elusive. Our comparative analysis of BCR and LMP2A now indicates that LMP2A is a true BCR mimic that dominates BCR-operated signaling pathways in EBV-infected, BCR-positive cells to provide activation signals, support stable infections in vivo and allow exit from latency. These findings suggest that LMP2A co-opts the situation in anergic B cells, where continuous BCR signaling results in maintenance of the anergic state accompanied by unresponsiveness to acute BCR stimulation. The microarray experiment was used to compare effects of BCR and LMP2A on gene expression regulation. EBV's LMP2A and the human BCR activate similar cellular target genes; some genes are regulated solely by BCR or LMP2A, no gene is counter regulated
2011-01-01 | GSE25434 | GEO
Project description:Epstein-Barr virus (EBV) infects human B cells and reprograms them to allow virus replication and persistence. One key viral factor in this process is latent membrane protein 2A (LMP2A), which has been described as a B cell receptor (BCR) mimic promoting malignant transformation. However, how LMP2A signaling contributes to tumorigenesis remains elusive. By systematically comparing LMP2A and BCR signaling using quantitative phosphoproteomics and transcriptome profiling, we identified molecular mechanisms through which LMP2A affects B cell biology. Consistent with previous literature, we found that LMP2A mimics a subset of BCR signaling events, including tyrosine-phosphorylation of the kinase SYK, the calcium initiation complex consisting of BLNK, BTK, PLC2, and its downstream transcription factor NFAT. However, the vast majority of LMP2A-induced signaling events markedly differed from those induced by BCR stimulation. These included differential phosphorylation of kinases, phosphatases, adaptor proteins, transcription factors such as NFB and TCF3, as well as widespread changes in the transcriptional output of LMP2A-expressing B cells. LMP2A affected apoptosis and cell cycle checkpoints by dysregulating the expression of apoptosis regulators such as Bcl-xL and the tumor suppressor retinoblastoma-associated protein (RB1). Accordingly, LMP2A cooperated with drivers of Burkitt lymphoma, overexpressed MYC and an oncogenic cyclin D3 mutant, by counteracting the pro-apoptotic effects of MYC and by further inhibiting RB1 function to promote cell growth. Our results indicate that LMP2A rewires rather than mimics BCR signaling, promoting a signaling output that predisposes EBV-infected B cells to hyperproliferation and eventual malignant transformation.
2020-09-22 | PXD018566 | Pride
Project description:Abstract: Epstein-Barr virus (EBV) infects germinal center (GC) B cells and establishes persistent infection in memory B cells. EBV-infected B cells sometimes cause B cell malignancies in humans with T- or NK-cell deficiency. We now find EBV-encoded Latent Membrane Protein 2A (LMP2A) to mimic B cell antigen receptor (BCR) signaling in murine GC B cells, causing altered humoral immune responses and autoimmune diseases. Investigation of the impact of LMP2A on B cell differentiation in mice that conditionally express LMP2A in GC B cells, or all B-lineage cells, found LMP2A expression enhanced not only BCR signals but also plasma-cell differentiation, in vitro and in vivo. Conditional LMP2A expression in GC B cells resulted in preferential selection of low-affinity antibody–producing B-cells despite apparently normal GC formation. GC B cell-specific LMP2A expression led to systemic lupus erythematosus-like autoimmune phenotypes in an age-dependent manner. Epigenetic profiling of LMP2A B cells found increased H3K27ac and H3K4me1 signals at the Zbtb20 locus. We conclude that LMP2A reduces the stringency of GC B cell selection and may contribute to persistent EBV infection and pathogenesis by providing GC B cells with pro-survival signals. Significance Statement: Epstein-Barr virus (EBV) is a human herpesvirus that establishes persistent infection of the B-cell compartment. EBV is associated with autoimmune diseases, including systemic lupus erythematosus (SLE). However, the molecular mechanisms by which EBV contributes to autoimmunity remain unclear. We used transgenic mouse models to study the role of EBV-encoded Latent membrane protein 2A (LMP2A), which mimics B-cell receptor signaling. Interestingly, LMP2A not only enhanced B-cell survival, but also upregulated the transcription factor Zbtb20 and promoted plasma cell differentiation. When expressed late in B-cell development, LMP2A also caused prominent features of SLE, including autoantibody production with kidney immune complex deposition. Our findings suggest that LMP2A has important roles in B cell activation, differentiation and the development of EBV-associated autoimmune diseases.
2015-10-01 | GSE71408 | GEO
Project description:Latent infection with Epstein-Barr virus (EBV) is recognised as a factor in the pathogenesis of nasopharyngeal carcinoma (NPC). We found that EBV encoded Latent membrane protein 2A (LMP2A) enhances lipid accumulation significantly in NPC cells. We used microarrays to identify differential genes regulated by LMP2A in NPC cell lines.
2018-08-21 | GSE118807 | GEO
Project description:LMP2A of Epstein-Barr virus is a receptor that mimics an activated B cell receptor, BCR. K1 and K15, related receptors of Kaposi sarcoma-associated herpes virus, KSHV, are expressed in virus-associated tumors but their functions are less obvious. We addressed this uncertainty with mutant EBVs encoding the KSHV genes K1 or K15 in lieu of LMP2A and infected primary human B cells with them. K1 and K15 encoded proteins appear to have noncomplementing redundant functions in this model but our findings suggest that both KSHV proteins can replace LMP2AM-bM-^@M-^Ys key activities contributing to the survival, activation and proliferation of B cells. We infected unsorted B cells with the four virus stocks, wt EBV, K1 EBV, K15 EBV or M-NM-^TLMP2A EBV, adjusted to yield similar rates of EBV-activated and growth transformed B cells. Eight days p.i. activated B cells in the lymphocyte gate were collected by FACS sorting and their RNAs analyzed with the aid of the Affymetrix GeneChip Human Gene 1.0 ST Array covering the whole transcriptome of approx. 29,000 annotated human genes. B cell preparations from four different donors were infected and analyzed accordingly.
2014-04-01 | E-GEOD-53914 | biostudies-arrayexpress
Project description:Epstein-Barr virus (EBV) reactivation in latently infected B cells is essential for persistent infection and B cell receptor (BCR) activation is a physiologically relevant stimulus for EBV reactivation. Post-translational modifications, such as phosphorylation and ubiquitination, are known to be regulated by antigen binding to BCR within minutes. However, a detailed understanding of the signaling alterations at later time when EBV is being actively replicated remains elusive. To gain insights into BCR activation-mediated reprogramming of the cellular environment in both Akata-BX1 (EBV+) and Akata-4E3 (EBV-) B cells, we utilized a 3-plex stable isotope labeling by amino acid in cell culture (SILAC)-based quantitative proteomic approach to monitor the dynamic changes of protein ubiquitination during the course of immunoglobulin G (IgG) cross-linking of BCRs. We observed temporal alterations in the level of ubiquitination on approximately 150 sites in both Akata-BX1 (EBV+) and Akata-4E3 (EBV-) B cells post-IgG cross-linking compared with no cross-linking controls, with the majority of protein ubiquitination down-regulated. Our analysis revealed that IgG cross-linking plays a major role in the regulation of protein ubiquitination in both EBV+ and EBV- B cells. Bioinformatic analyses of up-regulated ubiquitination events revealed significant enrichment of proteins involved in RNA processing. Among the down-regulated ubiquitination events are proteins enriched in apoptosis and the ubiquitin-proteasome pathway. The comparative and quantitative studies provide a foundation for further understanding how BCR activation regulates cellular protein ubiquitination and how EBV utilizes or subverts BCR engagement-mediated changes to facilitate viral replication.
2017-02-02 | PXD004562 | Pride
Project description:Upon Epstein-Barr virus (EBV) infection of human B lymphocytes non-coding RNAs (ncRNAs) regulate expression of viral and cellular genes. In this study, we generated a specialized cDNA library from EBV-immortalized cells and subjected it to deep sequencing. We identified 631 unique ncRNA genes, comprised of 321 potential novel differentially expressed ncRNA candidates. Subsequently, we investigated differential expression of known and potential novel ncRNA candidates by custom-designed microchips by comparing expression of ncRNA genes of EBV-immortalized versus non-infected control cells. Among the differentially expressed candidates from chip analysis, differential expression of six novel ncRNA candidates was verified by northern blot analysis. In addition, microchip analysis resulted in observation of increased expression levels of a significant number of potential ncRNA candidates that were preferentially derived from genomic loci annotated as Alu repetitive elements. Alu elements are members of the repeat subfamily of short interspersed nuclear elements (SINE) and were reported to be transcribed upon stress stimulation. While EBV infection significantly up-regulated expression of Alu-derived RNA transcripts, no significant increase in expression of these transcripts was observed under additional tested stress conditions. By employing deep sequencing followed by custom microchip analysis, we identified six novel differentially expressed ncRNAs as well as significantly increased expression levels of Alu-derived RNA transcripts. These transcripts might be involved in crucial functions upon infection by EBV. 5 biological replica of non-infected BL2 samples were compared to 5 biological replica of LCL 197/2 EBV immortalized samples
2010-10-30 | E-GEOD-20441 | biostudies-arrayexpress
Project description:This study characterizes the effects of Epstein-Barr virus (EBV) reactivation on the host and virus transcriptomes. For this work, a dual-fluorescent lytic reporter (DFLR) EBV was constructed based on the M81 EBV strain and used to transform primary B cells into lymphoblastoid cell lines (LCL). Deposited here is RNA-seq data from these DFLR LCLs that were induced by BCR crosslinking and sorted into latent, early lytic, and late lytic fractions. All samples consist of 40,000 sorted cells and include equal quantities of ERCC spike-in RNAs for normalization. We also performed the same experimental approach on a second DFLR LCL in which the EBV BGLF5 host shutoff nuclease was deleted. This allowed us to define which changes in the transcriptome during EBV replication were due to BGLF5. This approach demonstrated extensive shutoff of host genes during EBV replication and, unexpectedly, revealed that most of those changes were independent of BGLF5.
2024-07-08 | GSE271717 | GEO
Project description:The purpose of this study was to investigate the effect of EBV infection on host cell miR and to characterize the miRNome in EBV+ B cell lymphomas from patients with PTLD. A qPCR array was used to measure the expression level of 377 previously identified miRs from RNA isolated from three sources: total B cells isolated from healthy individuals (n=4), lymphoblastoid cell lines (LCL) generated by transformation of normal B cell with the B95-8 lab strain of EBV (n=4) and EBV+ B cell lines isolated from patients with PTLD (n=6). miRNA expression was assayed in total B cells samples (n = 4, in duplicate), in lymphoblastoid cell lines (n = 4, in duplicate) and in spontaneous lymphoblastoid cell lines derived from PTLD patients with EBV+ B cell lymphomas (n = 6 in duplicate). The expression of miRNA in the B cell samples was used as a control.
2014-09-10 | E-GEOD-61283 | biostudies-arrayexpress