Integrated analyses reveal CHD4 mediating establishment and maintenance of latent KSHV chromatin
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ABSTRACT:
PROVIDER: PRJNA687212 | ENA |
REPOSITORIES: ENA
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Project description:lncRNAs regulate protein functions via formation of protein-RNA complexes. Previous studies have shown that expression of viral lncRNA, polyadenylated nuclear RNA (PAN RNA) is essential for inducible viral genomic looping and distal gene activation during Kaposi's sarcoma-associated herpesvirus (KSHV) reactivation. Here we show an underlying molecular mechanism and regulation of KSHV latency by a viral lncRNA-CHD4 (chromodomain helicase DNA binding protein 4) interaction. Knock-out of the viral RNA binding protein, ORF57 protein, leads to decreased inducible and static viral genomic loops in latent chromatin and a failure to form RNA polymerase II aggregates in the nucleus during reactivation. We identified that CHD4's enzymatic activity silences viral gene expression by preventing nuclear aggregate formation. Furthermore, integrated genomic and proteomic studies together show that KSHV episomes frequently tether near the host cell centromeres and colocalize with a CHD4 protein complex, ChAHP. KSHV episomes detached from these sites when reactivation is triggered, and PAN RNA binds and inhibits CHD4 DNA binding in vitro. Our studies suggest that CHD4 exhibits strong repressor function by preventing inducible enhancer-promoter looping, and is therefore important for the ability of KSHV to establish and maintain latency in a “poised” state at specific host genomic loci.
2022-03-17 | GSE163098 | GEO
Project description:lncRNAs regulate protein functions via formation of protein-RNA complexes. Previous studies have shown that expression of viral lncRNA, polyadenylated nuclear RNA (PAN RNA) is essential for inducible viral genomic looping and distal gene activation during Kaposi's sarcoma-associated herpesvirus (KSHV) reactivation. Here we show an underlying molecular mechanism and regulation of KSHV latency by a viral lncRNA-CHD4 (chromodomain helicase DNA binding protein 4) interaction. Knock-out of the viral RNA binding protein, ORF57 protein, leads to decreased inducible and static viral genomic loops in latent chromatin and a failure to form RNA polymerase II aggregates in the nucleus during reactivation. We identified that CHD4's enzymatic activity silences viral gene expression by preventing nuclear aggregate formation. Furthermore, integrated genomic and proteomic studies together show that KSHV episomes frequently tether near the host cell centromeres and colocalize with a CHD4 protein complex, ChAHP. KSHV episomes detached from these sites when reactivation is triggered, and PAN RNA binds and inhibits CHD4 DNA binding in vitro. Our studies suggest that CHD4 exhibits strong repressor function by preventing inducible enhancer-promoter looping, and is therefore important for the ability of KSHV to establish and maintain latency in a “poised” state at specific host genomic loci.
2022-03-17 | GSE163694 | GEO
Project description:Integrated analyses reveal CHD4 mediating establishment and maintenance of latent KSHV chromatin [CUT&RUN]
| PRJNA684898 | ENA
Project description:Integrated analyses reveal CHD4 mediating establishment and maintenance of latent KSHV chromatin [Capture Hi-C]
| PRJNA687215 | ENA
Project description:Kaposi's sarcoma-associated herpesvirus (KSHV) establishes a latent infection, in which most viral genes are silenced except a few latent proteins such as latency-associated nuclear antigen (LANA). In latent viral chromatin, viral genes are poised to be transcribed, and KSHV LANA plays a major role in maintaining such transcription status. In the poised chromatins, LANA recruits cellular CHD4 (Chromodomain Helicase DNA binding protein 4) and suppresses inducible viral gene promoters. The CHD4 is known to regulate cell differentiation by restricting enhancer-promoter interactions and its mutation or overexpression deregulates the host cell transcription program and therefore associates with tumorigenesis. Here, we identified a putative CHD4 inhibitor from the LANA amino acid sequence from the LANA-CHD4 interaction surface. The small peptide interacts with CHD4 at its PHD domain with 14 nM KD (dissociation constant). The introduction of the peptide into the primary effusion lymphomas induces caspase-mediated CHD4 cleavage and subsequently triggered cell apoptosis and autophagy. A series of MTT assays demonstrated that the peptide preferentially killed lymphoma and leukemia cell lines at low micromolar concentrations, while peripheral mononuclear cells or adhesion cell lines were found to be more resistant to the peptide treatment. A monocyte cell differentiation model demonstrated that pre-treatment with the peptide at a low dose substantially enhanced transitioning into M2 macrophage (by reducing CHD4 occupancies from gene promoters), and globally altered the repertories of phorbol myristate acetate target genes in U937 cells. Finally, the PEL xenograft mouse model inhibited tumor growth without measurable side effects, and PEL cells isolated from xenograft tumors showed reduced CHD4 and LANA expression with terminally differentiated phenotype. We propose that the peptide isolated from the KSHV LANA sequence is biologically active and may function as a CHD4 inhibitor.
2024-03-01 | GSE228553 | GEO
Project description:Kaposi's sarcoma-associated herpesvirus (KSHV) establishes a latent infection, in which most viral genes are silenced except a few latent proteins such as latency-associated nuclear antigen (LANA). In latent viral chromatin, viral genes are poised to be transcribed, and KSHV LANA plays a major role in maintaining such transcription status. In the poised chromatins, LANA recruits cellular CHD4 (Chromodomain Helicase DNA binding protein 4) and suppresses inducible viral gene promoters. The CHD4 is known to regulate cell differentiation by restricting enhancer-promoter interactions and its mutation or overexpression deregulates the host cell transcription program and therefore associates with tumorigenesis. Here, we identified a putative CHD4 inhibitor from the LANA amino acid sequence from the LANA-CHD4 interaction surface. The small peptide interacts with CHD4 at its PHD domain with 14 nM KD (dissociation constant). The introduction of the peptide into the primary effusion lymphomas induces caspase-mediated CHD4 cleavage and subsequently triggered cell apoptosis and autophagy. A series of MTT assays demonstrated that the peptide preferentially killed lymphoma and leukemia cell lines at low micromolar concentrations, while peripheral mononuclear cells or adhesion cell lines were found to be more resistant to the peptide treatment. A monocyte cell differentiation model demonstrated that pre-treatment with the peptide at a low dose substantially enhanced transitioning into M2 macrophage (by reducing CHD4 occupancies from gene promoters), and globally altered the repertories of phorbol myristate acetate target genes in U937 cells. Finally, the PEL xenograft mouse model inhibited tumor growth without measurable side effects, and PEL cells isolated from xenograft tumors showed reduced CHD4 and LANA expression with terminally differentiated phenotype. We propose that the peptide isolated from the KSHV LANA sequence is biologically active and may function as a CHD4 inhibitor.
2024-03-01 | GSE228656 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2022-03-17 | GSE163695 | GEO
Project description:Gene expression profiling of three PEL cell lines compare to three Burkitt's lymphoma lines to figure out the changed genes under KSHV latent infection. Gene expression profiling of two time points on TIVE cells after infection by KSHV compare to TIVE cell without infection by KSHV to figure out the changed genes on TIVE cell under latent infection of KSHV. Gene expression profiling of four time points after inducing recombinant LANA protein expression when compare to no inducing BJAB/Tet-On/LANA cells to figure out the changed genes under the latency-associate nuclear antigen (LANA) of KSHV expression. Gene expression profiling of three time points after inducing recombinant LANA protein expression when compare to no inducing Jurkat/Tet-On/LANA cell line to figure out the changed genes under the latency-associate nuclear antigen (LANA) of KSHV expression. Gene expression profiling of two time points after inducing recombinant LANA protein expression when compare to no inducing 293/Tet-On/LANA cell line to figure out the changed genes under the latency-associate nuclear antigen (LANA) of KSHV expression. Keywords = TIVE Keywords = KSHV Keywords = LANA Keywords = PEL Keywords = BJAB Keywords = 293 Keywords = Jurkat Keywords: other
2004-10-27 | GSE1880 | GEO
Project description:Herpesvirus latency is generally thought to be governed by epigenetic modifications, but the dynamics of viral chromatin at early timepoints of latent infection are poorly understood. Here, we report a comprehensive spatial and temporal analysis of epigenetic modifications during latent infection with Kaposi's sarcoma associated herpesvirus (KSHV), the etiologic agent of Kaposi's sarcoma and primary effusion lymphoma (PEL). Using high resolution tiling microarrays in conjunction with immunprecipitation of methylated DNA (MeDIP) and modified histones (ChIP), we have determined global patterns of epigenetic modifications across the KSHV genome in several tumor-derived cell lines as well as de novo infected endothelial cells, revealing highly distinct landscapes of epigenetic modifications associated with latent KSHV infection. We find that KSHV genomes are subject to profound methylation at CpG dinucleotides, leading to the establishment of characteristic global DNA methylation patterns. However, such patterns evolved slowly and thus are unlikely to govern latency early during the infection process. In contrast, we observed that latent histone modification patterns were rapidly established upon a de novo infection. Our analysis furthermore demonstrates that such patterns are not characterized by the absence of activating histone modifications, since both H3K9/K14-ac and H3K4-me3 marks were prominently detected at several loci, including the promoter of the lytic cycle transactivator Rta. While these regions were furthermore largely devoid of the constitutive heterochromatin marker H3K9-me3, we observed rapid and widespread deposition of H3K27-me3 across latent KSHV genomes, a bivalent modification which is able to repress transcription despite of the simultaneous presence of activating marks. Our findings suggest that the epigenetic patterns identified here induce a poised state of repression during viral latency, which can be rapidly reversed once the lytic cycle is induced. This dataset contains our ChIP-on-chip data; the MeDIP data are deposited in a separate dataset.
2010-06-07 | GSE19906 | GEO