Project description:We used Precision Nuclear Run-on followed by Deep Sequencing (PRO-Seq) to investigate RNA Polymerase (Pol) activity during Epstein-Barr Virus (EBV) reactivation and its link to CTCF in latently EBV infected ymphoblastoid cell lines (LCLs). Nuclei were harvested from WT LCLs or LCLs containing an 18bp deletion at the LMP CTCF binding site (DCTCF) treated with DMSO or induced to reactivate with the small molecule C60 for 24h. Relative to WT, DCTCF displayed disrupted transcriptional activity at other CTCF sites during latency and this phenotype correlated with an inability to reactivate from latency.
Project description:Our group has previously identified how PARP1 can control EBV latency by: (1) altering the 3D virus chromatin structure [28]; (2) regulating CTCF binding on EBV promoters and supporting the latency expression program [29-32]; (3) repressing the lytic gene expression by binding BZLF1 promoter [33, 34]. To date, the therapeutic effect of PARP1 inhibitors on EBV+ lymphomagenesis has been poorly explored. Therefore, we aimed to investigate whether PARP1i was able to counteract EBV-driven tumors in a LCL xenograft model and identify, and confirm, possible mechanisms underlying its therapeutic effect. In the present study we demonstrate that PARP1 inhibition restricts EBV-driven lymphoma in vivo, pointing out the oncogene MYC as its functional target. Specifically, PARP1 inhibition reverts the tumor growth and the metastatic potential of EBV+ LCL, inducing a dramatic transcriptional reprogramming. Interestingly, the absence of PARP1 activity causes a decrease in MYC expression, subsequently leading to a dysregulation of MYC-associated co-factors and targets, both in vivo and in vitro. Our findings also corroborate the link between PARP1 and EBNA2 expression, that we previously demonstrated in vitro. Overall, our study strengthens the central role of PARP1 in EBV malignant transformation and outlines the EBNA2/MYC pathway as an additional target of PARP1 regulation in LCL
Project description:This SuperSeries is composed of the following subset Series: GSE31485: CTCF promotes RNA pol II pausing and links DNA methylation to alternative splicing [ChIP-Seq] GSE31486: CTCF promotes RNA pol II pausing and links DNA methylation to alternative splicing [RNA-Seq] Refer to individual Series
Project description:DNA from Epstein-Barr virus (EBV)-transformed lymphocyte cell lines (LCLs) has proven very useful for studies of genetic sequence polymorphisms. Whether EBV-LCL DNA is suitable for methylation studies is less clear. We conduct a genome-wide methylation investigation using an array set with 45 million probes to investigate the methylome of EBV-LCL DNA and technical duplicates of whole blood (WB) DNA from the same 10 individuals. Methylation sites that show variation between individuals are potentially useful as biomarkers in disease studies. Our comparison is, therefore, focused specifically on these methylation variable sites. The sample correlations (i.e., a measure of whether the rank of the signals remains consistent between two samples from the same individual) for the methylation variable probes ranged from 0.69-0.78 for the WB duplicates and from 0.27-0.72 for WB versus EBV-LCL. To compare the pattern of the methylation signals, we grouped adjacent probes based on their inter-correlations. These analyses showed ~29,000 blocks in WB and ~14,000 blocks in EBV-LCL. Furthermore, merely 31% of the methylated regions detected in WB were detectable in EBV-LCLs. Our study shows that there are substantial differences in the DNA methylation patterns between EBV-LCL and WB. Thus, EBV-LCL DNA cannot be used as a proxy for WB DNA in methylation studies.
Project description:DNA from Epstein-Barr virus (EBV)-transformed lymphocyte cell lines (LCLs) has proven very useful for studies of genetic sequence polymorphisms. Whether EBV-LCL DNA is suitable for methylation studies is less clear. We conduct a genome-wide methylation investigation using an array set with 45 million probes to investigate the methylome of EBV-LCL DNA and technical duplicates of whole blood (WB) DNA from the same 10 individuals. Methylation sites that show variation between individuals are potentially useful as biomarkers in disease studies. Our comparison is, therefore, focused specifically on these methylation variable sites. The sample correlations (i.e., a measure of whether the rank of the signals remains consistent between two samples from the same individual) for the methylation variable probes ranged from 0.69-0.78 for the WB duplicates and from 0.27-0.72 for WB versus EBV-LCL. To compare the pattern of the methylation signals, we grouped adjacent probes based on their inter-correlations. These analyses showed ~29,000 blocks in WB and ~14,000 blocks in EBV-LCL. Furthermore, merely 31% of the methylated regions detected in WB were detectable in EBV-LCLs. Our study shows that there are substantial differences in the DNA methylation patterns between EBV-LCL and WB. Thus, EBV-LCL DNA cannot be used as a proxy for WB DNA in methylation studies. The methylation of technical duplicates of DNA extracted from whole blood from 10 individuals, as well as DNA extracted from EBV-transformed lymphocyte cell lines (EBV-LCL) from the same samples of whole blood, are investigated using the Affymetrix GeneChip Human Tiling 2.0R array set. In total, 30 samples from 10 individuals were investigated on 7 arrays. The supplementary "GSE35204_ChrXX_bgc_qt.txt" files contain the background-corrected and quantile-normalized data for all 30 samples per chromosome. The files include 32 columns: 'Seq' refers to the chromosome, 'Pos' indicates the position in the genome on that chromosome, and columns 3-32 indicate the sample numbers.
Project description:Epstein-Barr-Virus (EBV) Nuclear Antigens EBNALP and EBNA2 are co-expressed in EBV infected B-lymphocytes and are critical for Lymphoblastoid Cell Line (LCL) growth. EBNALP removes NCOR1 and RBPJ repressive complexes from promoter and enhancer sites and EBNA2 mostly activates transcription from distal enhancers. ChIP-seqs found EBNALP at 19,224 LCL sites, which were 33% promoter associated. EBNALP was associated with 10 transcription factor (TF) clusters that included YY1(63%), SP1(62%), PAX5(59%), BATF(50%), IRF4(49%), RBPJ(43%), ETS1(39%), PU.1(37%), RAD21(33%), NF-kB(31%), TBLR1(26%), ZNF143(24%), CTCF(23%), SMC3(21%), and EBF(17%). EBNALP sites had higher H3K4me3, H3K9ac, H3K27ac, H2Az, and RNA Pol II signals than EBNA2 sites and had similar transcription effects. EBNALP co-localized with 29% of 19,845 EBNA2 sites. EBNALP/EBNA2 sites were similar to EBNALP sites in promoter localization, associated cell TFs, Pol II, H3K4me3, H3K9ac, H3K27ac, and H2Az signals. EBNALP and EBNA2 promoter sites were more transcriptionally active than EBNALP or EBNA2 promoter sites. EBNALP was at the enhancer or promoter of myc and MYC affected genes, including cyclin D2, and bcl2. EBNALP at promoters with DNA looping and transcription factors, is positioned to deplete repressors from enhancers and promoters, enable chromatin remodeling, and transcription activation. Two EBNALP ChIP-seq replicates from IB4 LCL are analyzed in this study.
Project description:We used Precision Nuclear Run-on followed by Deep Sequencing (PRO-Seq) to investigate RNA Polymerase (Pol) activity during Epstein-Barr Virus (EBV) reactivation in EBV positive Burkitt's lymphoma cell lines Mutu-I and Akata. Nuclei were harvested from latent cells and after treatment with NaB/TPA (Mutu-I) or anti-IgG (akata) to stimulate reactivation at 1 and 4 and 12h. We identified multiple sites on the EBV genome enriched with Pol displaying distinct patterns of activity, which showed an association with CTCF and open chromatin.
Project description:Glycosylation of proteins is an important post-translational modification that comprises two major stages: synthesis and attachment of glycans in the endoplasmic reticulum (ER), and glycan remodeling in the ER and Golgi apparatus (GA). Genetic disorders impairing a step of this process give rise to a group of pathologies named congenital disorders of glycosylation (CDG). The most common CDG type is PMM2-CDG, caused by mutations on PMM2 (phosphomannomutase 2) genes. PMM2-CDG clinical presentation vary among affected individuals. CDG condition is considered a form of chronic ER stress. Inhibition of glycosylation results in the accumulation of misfolded proteins in the ER, which induces a complex protective reaction known as the unfolded protein response (UPR), which includes translational repression, transcriptional activation of ER chaperones, and ER-associated degradation of unfolded proteins. In search for CDG biomarkers, EBV-transformed CDG B-lymphoblastoid cell lines (B-LCL) were used as cellular models due to two main advantages: first, B-LCL are secretory cells that are forced to continuously synthetize proteins such as immunoglobulins, cytokines or other cell to cell communication molecules, so their ER is chronically stressed; second, as immune system cells, they express common genes and share common regulatory mechanisms with nervous system cells such as neurons (affected cell in most CDG patients). In this work we generated a collection of 7 EBV-transformed PMM2-CDG B-LCL by culture of patients' purified blood B lymphocytes with supernatants of the marmoset EBV-leukocyte cell line B95-8, and compared their transcriptome with that of 7 EBV-transformed healthy B-LCL. Our analysis revealed 348 significantly up-regulated and 106 down-regulated protein-coding genes compared to non-CDG cell lines, which included response to stress, transcription factors, glycosylation, motility and cell junction, development and cell (neuron) differentiation and synapse genes. Gene Set Enrichment Analysis (GSEA) identified biological consequences associated to gene expression changes in PMM2-CDG cells related to the unfolded protein response (UPR), RNA metabolism and the endoplasmic reticulum, Golgi apparatus and mitochondria components. Dysregulated important genes were MAN1A1, MGAT2, CHST4, LARGE, ADAM23, SEMA4D, UNC13C, AUTS2, CA2, SMN1, EXOSC2 expressed not only in the immune system but in other tissues including the nervous system that were compatible with CDG pathophysiology. Our results confirm PMM2-CDG EBV-transformed B-LCL as a suitable cell model that expands both our knowledge and tools to study CDG pathology at the cellular level, useful for functional characteristics and potential therapeutic drugs testing.