Genome-wide mapping of RTA binding sites in KSHV+ PEL cells during KSHV reactivation.
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PROVIDER: PRJNA510137 | ENA |
REPOSITORIES: ENA
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Project description:Chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) analysis was performed during Kaposi's sarcoma-associated herpesvirus (KSHV) reactivation in KSHV+ recombinant primary effusion B-cell lymphoma cells (PEL). RTA binding sites were identified genome-wide in a recombinant PEL cell line called TRExBCBL1-3xFLAG-RTA cells at 12 hours post-induction (hpi) of RTA expression.
2019-01-09 | GSE123897 | GEO
Project description:Kaposi's sarcoma-associated herpesvirus (KSHV) is a human oncogenic virus, which maintains the persistent infection of the host by intermittently reactivating from latently infected cells to produce viral progenies. Here, we performed a comprehensive time course transcriptome analysis during KSHV reactivation in KSHV+ primary effusion B-cell lymphoma cells (PEL). For this we used a recombinant PEL cell line called TRExBCBL1-3xFLAG-RTA. The expression of the N-terminally 3xFLAG-tagged RTA was induced by adding 1 μg/ml doxycycline (Dox) to the medium. Total gene expression changes were identified in TRExBCBL1-3xFLAG-RTA cells at 0, 6, 12, and 24 hours post-induction (hpi).
2019-01-09 | GSE123898 | GEO
Project description:The three-dimensional structure of chromatin via formation of genomic loops allows cellular RNA polymerase II to access distal promoters, thus it has a significant impact on the outcome of gene expression. The Kaposi’s sarcoma-associated herpesvirus (KSHV) entire lytic transcriptional program of 80 plus genes is initiated by a single viral transactivator, K-Rta. Here we examined the relationship between the KSHV genomic structure and K-Rta recruitment sites with unbiased Capture Hi-C analyses. The studies showed that KSHV forms a unique genomic structure, which coordinates a domain-specific viral gene expression program via K-Rta recruitment, and identified a number of direct physical, long-range, and dynamic genomic interactions. Chromatin immunoprecipitation-sequencing analyses identified a limited number of K-Rta recruitment sites in the KSHV genome, including the K12 and PAN RNA promoters. KSHV engineered to harbor point mutations in the K-Rta-responsive elements (RE) at these promoters significantly attenuated not only the direct downstream gene, but also distal viral gene expression in a domain-specific manner. Despite the long distance between two RE sites in the linear orientation, efficient recruitment of K-Rta to either promoter required intact K-Rta REs at both promoters. Finally, inducible genomic loops generated during KSHV reactivation occurred preferentially at K-Rta recruitment sites. Mutation of a K-Rta RE inhibited formation of inducible genomic loops, gene expression of its destination of looping genes, and KSHV replication in de novo infected human gingival epithelial cells. These results suggest that the KSHV genome is programed to form both stable and inducible chromatin hubs for effective KSHV gene expression, and partly explains why K-Rta has such a dominant effect on KSHV lytic gene transcription.
2018-01-22 | GSE99943 | GEO
Project description:Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiologic agent of primary effusion lymphoma (PEL). All PEL cell lines are infected with KSHV, and 70% are co-infected with Epstein-Barr Virus (EBV). KSHV reactivation from latency requires promoter-specific transactivation by the KSHV Rta protein through interactions with RBP-Jk (CSL), the cellular DNA binding component of the Notch signal transduction pathway. EBV transformation of primary B cells requires EBV nuclear antigen (EBNA)-2 to interact with RBP-Jk to direct the latent viral and cellular gene expression program. Although KSHV Rta and EBV EBNA-2 both require RBP-Jk for transactivation, previous studies have suggested that RBP-Jk-dependent transactivators do not function identically. We have found that the EBV latent protein LMP-1 is expressed in less than 5% of KSHV+/EBV+ PEL cells, but is induced in an Rta-dependent fashion when KSHV reactivates. KSHV Rta transactivates the EBV latency promoters in an RBP-Jk-dependent fashion and forms a ternary complex with RBP-Jk on the promoters. In B cells that are conditionally transformed by EBV alone, we show that KSHV Rta complements a short-term EBNA2 growth deficiency in an autocrine/paracrine manner. Complementaton of EBNA2-deficiency by Rta depends on RBP-Jk and LMP-1, and Rta transactivation is required for optimal growth of KSHV+/EBV+ PEL lines. Our data suggest that Rta can contribute to EBV-driven cellular growth by transactivating RBP-Jk-dependent EBV latency genes. However, our data also suggest that EBNA2 and Rta induce distinct alterations in the cellular proteomes that contribute to growth of infected cells.
2010-12-31 | GSE21375 | GEO
Project description:Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiologic agent of primary effusion lymphoma (PEL). All PEL cell lines are infected with KSHV, and 70% are co-infected with Epstein-Barr Virus (EBV). KSHV reactivation from latency requires promoter-specific transactivation by the KSHV Rta protein through interactions with RBP-Jk (CSL), the cellular DNA binding component of the Notch signal transduction pathway. EBV transformation of primary B cells requires EBV nuclear antigen (EBNA)-2 to interact with RBP-Jk to direct the latent viral and cellular gene expression program. Although KSHV Rta and EBV EBNA-2 both require RBP-Jk for transactivation, previous studies have suggested that RBP-Jk-dependent transactivators do not function identically. We have found that the EBV latent protein LMP-1 is expressed in less than 5% of KSHV+/EBV+ PEL cells, but is induced in an Rta-dependent fashion when KSHV reactivates. KSHV Rta transactivates the EBV latency promoters in an RBP-Jk-dependent fashion and forms a ternary complex with RBP-Jk on the promoters. In B cells that are conditionally transformed by EBV alone, we show that KSHV Rta complements a short-term EBNA2 growth deficiency in an autocrine/paracrine manner. Complementaton of EBNA2-deficiency by Rta depends on RBP-Jk and LMP-1, and Rta transactivation is required for optimal growth of KSHV+/EBV+ PEL lines. Our data suggest that Rta can contribute to EBV-driven cellular growth by transactivating RBP-Jk-dependent EBV latency genes. However, our data also suggest that EBNA2 and Rta induce distinct alterations in the cellular proteomes that contribute to growth of infected cells. EREB2-5 cells were transfected and grown in the presence or absence of β-estradiol, as described. Seven days post-transfection, protein extracts were prepared, and 200 ugs. of each were analyzed using the RayBio Human Apoptosis Antibody Array Kit (RayBiotech) as per manufacturers suggestions. The membranes were exposed to autoradiography film for different times to detect the chemiluminescent signals. Images with signals in linear range were quantitated using the program ImageJ [59]. For each membrane, signals from the negative control spots were averaged, and then subtracted from each of the other spots. A signal was considered valid if its value exceeded both its average local background, and the average of all valid negative control values. Valid signals were normalized using the positive control spots (for cellular BID protein). Fold change in signals for each spot were quantitated by dividing by the valid signals for each corresponding spot on the minus β-estradiol membrane. Average fold change, and standard deviation, were calculated for each protein.
2010-12-31 | E-GEOD-21375 | biostudies-arrayexpress
Project description:Primary effusion lymphoma (PEL) is an aggressive subtype of non-Hodgkin lymphoma caused by Kaposi’s sarcoma-associated herpesvirus infection, which is most commonly seen in HIV-positive patients. Induction of HIV reactivation by external stimuli in the presence of highly active anti-retroviral therapy (HAART) has been examined for its efficacy to eradicate latently infected HIV. Similary, lytic activation of viruses from latently infected tumor cells with anti-cancer drugs represents an effective strategy of anti-neoplastic therapy, through the induction of oncolysis by viral replication, stimulation of immune responses to the viral lytic antigens, and intrinsic effects of cancer drugs. Here we examined the combination of PEP005 with epigenetic drugs as a rational therapeutic strategy to target both in AIDS-associated KSHV-mediated malignancies. JQ1, a bromodomain and extra terminal protein (BET) inhibitor, in combination with a FDA-approved drug, PEP005, not only robustly induced KSHV lytic replication, but also inhibited IL-6 and VEGF production from PEL cells. This combination has been proposed for use in reactivation of HIV from latently infected T-cells, and the same combination and dosage inhibited PEL growth in vitro and delayed tumor growth in a PEL xenograft tumor model. Downstream activation of NF-B by PEP005 combined with sequestration of bromodomain-containing protein 4 (BRD4) by JQ1 robustly increased occupancy of RNA polymerase II onto the KSHV genome. RNA-sequencing analysis further revealed cellular targets of PEP005, JQ1, and the synergistic effects of both. We suggest that the combination of PEP005 with JQ1 should be considered as a rational therapeutic approach for HIV-associated PEL.
2017-11-03 | GSE89478 | GEO
Project description:Lytic reactivation from latency is critical for the pathogenesis of KSHV. We previously demonstrated that the 691 amino acid KSHV Rta transcriptional transactivator is necessary and sufficient to reactivate the virus from latency. Viral lytic cycle genes, including those expressing additional transactivators and putative oncogenes, are induced in a cascade fashion following Rta expression. In this study, we sought to define Rta’s direct targets during reactivation by generating a conditionally nuclear variant of Rta. WT Rta protein is constitutively localized to cell nuclei, and contains two putative nuclear localization signals (NLSs). Only one NLS (NLS-2; aa 516-530) was required for nuclear localization of Rta, and relocalized eGFP exclusively to cell nuclei. Analyses of Rta NLS mutants demonstrated that proper nuclear localization of Rta was required for transactivation and stimulation of viral reactivation. Fusion of Rta_NLS-1,2 to the hormone binding domain of the murine estrogen receptor generated a variant of Rta whose nuclear localization and ability to transactivate and induce reactivation were tightly controlled post-translationally by the synthetic hormone tamoxifen. We used this strategy in KSHV-infected cells treated with protein synthesis inhibitors to identify direct transcriptional targets of Rta. Only eight KSHV genes were activated by Rta in the absence of de novo protein synthesis. These direct transcriptional targets of Rta were transactivated to different magnitudes, and included the genes nut-1/PAN, ORF57/Mta, ORF56/Primase, K2/vIL-6, ORF37/SOX, K14/vOX, K9/vIRF1, and ORF52. Our data suggest that induction of most of the KSHV lytic cycle genes requires additional protein expression post-Rta. Keywords: Comparative transcriptome analysis by oligonucleotide microarray
2008-08-31 | GSE11432 | GEO
Project description:The objective of this study was to identify the binding sites of KSHV encoded imemdiate early protein, RTA and early protein, K8 on KSHV genome by chromatin immunoprecipitation assay and sequencing of the DNA bound to RTA and K8
2016-06-07 | GSE82283 | GEO
Project description:Primary effusion lymphoma (PEL) is an aggressive subtype of non-Hodgkin lymphoma caused by Kaposi's sarcoma-associated herpesvirus (KSHV) infection. Currently, treatment options for patients with PEL are limited. Oncolytic viruses have been engineered as anticancer agents and have recently shown increased therapeutic promise. Similarly, lytic activation of endogenous viruses from latently infected tumor cells can also be applied as a cancer therapy. In theory, such a therapeutic strategy would induce oncolysis by viral replication, while simultaneously stimulating an immune response to viral lytic cycle antigens. We examined the combination of the FDA-approved drug ingenol-3-angelate (PEP005) with epigenetic drugs as a rational therapeutic approach for KSHV-mediated malignancies. JQ1, a bromodomain and extra terminal (BET) protein inhibitor, in combination with PEP005, not only robustly induced KSHV lytic replication, but also inhibited IL6 production from PEL cells. Using the dosages of these agents that was found to be effective in reactivating HIV (as a means to clear latent virus with highly active antiretroviral therapy), we were able to inhibit PEL growth in vitro and delay tumor growth in a PEL xenograft tumor model. KSHV reactivation was mediated by activation of NF-kB pathway by PEP005, which led to increased occupancy of RNA polymerase II onto the KSHV 33 genome. RNA-sequencing analysis further revealed cellular targets of PEP005, JQ1, and the synergistic effects of both. Thus, combination of PEP005 with a BET inhibitor may be considered as a rational therapeutic approach for the treatment of PEL.
2017-10-24 | GSE103395 | GEO
Project description:Global host gene expression changes in KSHV+ PEL cells upon KSHV reactivation
| PRJNA510136 | ENA