scholarly journals Regulation of host and viral promoters during human cytomegalovirus latency via US28 and CTCF

2021 ◽  
Vol 102 (5) ◽  
Author(s):  
Elizabeth G. Elder ◽  
Benjamin A. Krishna ◽  
Emma Poole ◽  
Marianne Perera ◽  
John Sinclair
Keyword(s):  
Gene Expression ◽  
Human Cytomegalovirus ◽  
Ctcf Binding ◽  
Dependent Manner ◽  
Gene Promoters ◽  
Cellular Gene ◽  
Control Gene Expression ◽  
Viral Promoters ◽  
G Protein Coupled ◽  
Major Immediate Early Promoter

Viral latency is an active process during which the host cell environment is optimized for latent carriage and reactivation. This requires control of both viral and host gene promoters and enhancers often at the level of chromatin, and several viruses co-opt the chromatin organiser CTCF to control gene expression during latency. While CTCF has a role in the latencies of alpha- and gamma-herpesviruses, it was not known whether CTCF played a role in the latency of the beta-herpesvirus human cytomegalovirus (HCMV). Here, we show that HCMV latency is associated with increased CTCF expression and CTCF binding to the viral major lytic promoter, the major immediate early promoter (MIEP). This increase in CTCF binding is dependent on the virally encoded G protein coupled receptor, US28, and contributes to suppression of MIEP-driven transcription, a hallmark of latency. Furthermore, we show that latency-associated upregulation of CTCF represses expression of the neutrophil chemoattractants S100A8 and S100A9 which we have previously shown are downregulated during HCMV latency. As with downregulation of the MIEP, CTCF binding to the enhancer region of S100A8/A9 drives their suppression, again in a US28-dependent manner. Taken together, we identify CTCF upregulation as an important mechanism for optimizing latent carriage of HCMV at both the levels of viral and cellular gene expression.

scholarly journals Hesx1 homeodomain protein represses transcription as a monomer and antagonises transactivation of specific sites as a homodimer

2002 ◽  
Vol 28 (3) ◽  
pp. 193-205 ◽  
Author(s):  
J Quirk ◽  
P Brown
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Binding Site ◽  
Anterior Pituitary ◽  
Homeodomain Protein ◽  
Dependent Manner ◽  
Gene Promoters ◽  
Differentiation Markers ◽  
Proximal Half ◽  
Dna Binding Site

The homeobox repressor Hesx1, expressed throughout Rathke's pouch and required for normal pituitary development, has been implicated in anterior pituitary pathogenesis in man. Prolonged expression of Hesx1 delays the appearance of anterior pituitary terminal differentiation markers in mice, particularly the gonadotroph hormones. We tested if Hesx1 could modulate gonadotrophin gene expression directly, and found that Hesx1 repressed both common alpha subunit (alpha GSU) and luteinising hormone beta-subunit (LH beta) gene promoters. Repression mapped to the Pitx1 homeodomain protein transactivation site in the proximal alpha GSU promoter, but did not map to the equivalent site on LH beta. Hesx1 repression of the alpha GSU Pitx1 site was overridden by co-transfection of Pitx1. In contrast, Hesx1 antagonised Pitx1 transactivation of LH beta in a dose-dependent manner. This was due to monomeric binding of Hesx1 on alpha GSU and homodimerisation on LH beta. The homodimerisation site comprises the Pitx1 DNA binding site and a proximal binding site, and mutation of either inhibited homodimer formation. Conversion of the LH beta Pitx1 DNA binding site to an alpha GSU-type did not promote homodimer formation, arguing that Hesx1 has pronounced site selectivity. Furthermore, mutation of the proximal half of the homodimerisation site blocked Hesx1 antagonisation of Pitx1 transactivation. We conclude that Hesx1 monomers repress gene expression, and homodimers block specific transactivation sites.

Abstract 40: Disturbed Flow Alters Genomewide DNA Methylation Patterns, Regulating Endothelial Gene Expression and Atherosclerosis

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Jessilyn Dunn ◽  
Haiwei Qiu ◽  
Soyeon Kim ◽  
Daudi Jjingo ◽  
Ryan Hoffman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Dna Methyltransferase ◽  
Methylation Status ◽  
Western Diet ◽  
Dependent Manner ◽  
Gene Promoters ◽  
Genome Wide ◽  
Methylation Patterns ◽  
Endothelial Gene Expression

Atherosclerosis preferentially occurs in arterial regions of disturbed blood flow (d-flow), which alters gene expression, endothelial function, and atherosclerosis. Here, we show that d-flow regulates genome-wide DNA methylation patterns in a DNA methyltransferase (DNMT)-dependent manner. We found that d-flow induced expression of DNMT1, but not DNMT3a or DNMT3b, in mouse arterial endothelium in vivo and in cultured endothelial cells by oscillatory shear (OS) compared to unidirectional laminar shear in vitro. The DNMT inhibitor 5-Aza-2’deoxycytidine (5Aza) or DNMT1 siRNA significantly reduced OS-induced endothelial inflammation. Moreover, 5Aza reduced lesion formation in two atherosclerosis models using ApoE-/- mice (western diet for 3 months and the partial carotid ligation model with western diet for 3 weeks). To identify the 5Aza mechanisms, we conducted two genome-wide studies: reduced representation bisulfite sequencing (RRBS) and transcript microarray using endothelial-enriched gDNA and RNA, respectively, obtained from the partially-ligated left common carotid artery (LCA exposed to d-flow) and the right contralateral control (RCA exposed to s-flow) of mice treated with 5Aza or vehicle. D-flow induced DNA hypermethylation in 421 gene promoters, which was significantly prevented by 5Aza in 335 genes. Systems biological analyses using the RRBS and the transcriptome data revealed 11 mechanosensitive genes whose promoters were hypermethylated by d-flow but rescued by 5Aza treatment. Of those, five genes contain hypermethylated cAMP-response-elements in their promoters, including the transcription factors HoxA5 and Klf3. Their methylation status could serve as a mechanosensitive master switch in endothelial gene expression. Our results demonstrate that d-flow controls epigenomic DNA methylation patterns in a DNMT-dependent manner, which in turn alters endothelial gene expression and induces atherosclerosis.

scholarly journals Lytic infection of permissive cells with human cytomegalovirus is regulated by an intrinsic ‘pre-immediate-early’ repression of viral gene expression mediated by histone post-translational modification

2009 ◽  
Vol 90 (10) ◽  
pp. 2364-2374 ◽  
Author(s):  
Ian J. Groves ◽  
Matthew B. Reeves ◽  
John H. Sinclair
Keyword(s):  
Gene Expression ◽  
Human Cytomegalovirus ◽  
Chromatin Structure ◽  
Viral Gene Expression ◽  
Lytic Infection ◽  
Immediate Early ◽  
Late Gene ◽  
Viral Gene ◽  
Gene Promoters ◽  
Late Gene Expression

Human cytomegalovirus (HCMV) lytic gene expression occurs in a regulated cascade, initiated by expression of the viral major immediate-early (IE) proteins. Transcribed from the major IE promoter (MIEP), the major IE genes regulate viral early and late gene expression. This study found that a substantial proportion of infecting viral genomes became associated with histones immediately upon infection of permissive fibroblasts at low m.o.i. and these histones bore markers of repressed chromatin. As infection progressed, however, the viral MIEP became associated with histone marks, which correlate with the known transcriptional activity of the MIEP at IE time points. Interestingly, this chromatin-mediated repression of the MIEP at ‘pre-IE’ times of infection could be overcome by inhibition of histone deacetylases, as well as by infection at high m.o.i., and resulted in a temporal advance of the infection cycle by inducing premature viral early and late gene expression and DNA replication. As well as the MIEP, and consistent with previous observations, the viral early and late promoters were also initially associated with repressive chromatin. However, changes in histone modifications around these promoters also occurred as infection progressed, and this correlated with the known temporal regulation of the viral early and late gene expression cascade. These data argue that the chromatin structure of all classes of viral genes are initially repressed on infection of permissive cells and that the chromatin structure of HCMV gene promoters plays an important role in regulating the time course of viral gene expression during lytic infection.

scholarly journals Human Cytomegalovirus IE72 Protein Interacts with the Transcriptional Repressor hDaxx To Regulate LUNA Gene Expression during Lytic Infection

2010 ◽  
Vol 84 (14) ◽  
pp. 7185-7194 ◽  
Author(s):  
Matthew Reeves ◽  
David Woodhall ◽  
Teresa Compton ◽  
John Sinclair
Keyword(s):  
Gene Expression ◽  
Human Cytomegalovirus ◽  
Direct Interaction ◽  
Lytic Infection ◽  
Early Gene ◽  
Productive Infection ◽  
Viral Promoters ◽  
Infected Cells ◽  
Sirna Knockdown ◽  
Interfering Rna

ABSTRACT A putative latency-associated transcript (LUNA) complementary to the human cytomegalovirus (HCMV) UL81-82 region previously identified in seropositive donors' monocytes is also expressed during lytic infection. Thus, the LUNA promoter is active during both lytic and latent infection. Consequently, the mechanisms regulating this promoter may provide further insight into factors that determine whether the outcome of HCMV infection is latent or lytic. By transfection, the LUNA promoter exhibited low but reproducible activity. Substantial activation by virus infection suggested that a viral factor was important for LUNA expression during lytic infection. IE72, a known transactivator of viral promoters, activated the LUNA promoter in cotransfection assays. Furthermore, coinfection with wild-type HCMV but not an IE72 deletion virus (CR208) also activated the LUNA promoter. Finally, diminished LUNA gene expression in CR208 virus-infected cells supported a role for IE72 in LUNA gene expression. The initial regulation of herpesvirus immediate-early gene expression is associated with proteins found at cellular nuclear domain 10 (ND10) bodies, such as PML, hDaxx, and ATRX. hDaxx transfection repressed LUNA promoter activity. Furthermore, we observed binding of hDaxx to the LUNA promoter, which was abrogated by IE72 gene expression via direct interaction. Finally, we show that small interfering RNA (siRNA) knockdown of the hDaxx interaction partner ATRX rescued LUNA gene expression in CR208-infected cells. Overall, these data show that hDaxx/ATRX-mediated repression of LUNA during lytic infection absolutely requires IE72 gene expression. It also suggests that the targeting of cellular factors by IE72 is important throughout the different phases of HCMV gene expression during productive infection.

scholarly journals The IE2 60-Kilodalton and 40-Kilodalton Proteins Are Dispensable for Human Cytomegalovirus Replication but Are Required for Efficient Delayed Early and Late Gene Expression and Production of Infectious Virus

2007 ◽  
Vol 81 (6) ◽  
pp. 2573-2583 ◽  
Author(s):  
Elizabeth A. White ◽  
Christia J. Del Rosario ◽  
Rebecca L. Sanders ◽  
Deborah H. Spector
Keyword(s):  
Gene Expression ◽  
Human Cytomegalovirus ◽  
Infectious Virus ◽  
Deletion Mutants ◽  
Wild Type ◽  
Late Gene Expression ◽  
Cellular Gene ◽  
C Terminus ◽  
Viral Genes ◽  
Early Transcription

ABSTRACT The human cytomegalovirus (HCMV) IE2 86-kDa protein is an essential transactivator of viral and cellular gene expression. Additional proteins of 60 and 40 kDa are expressed from the IE2 gene at late times postinfection and are identical to the C terminus of IE2 86. We have constructed HCMV recombinants that express wild-type full-length IE2 86 but do not express the IE2 40- and 60-kDa proteins. Each of these recombinants is viable, indicating that neither the 60-kDa nor the 40-kDa protein is required for virus replication, either alone or in combination. Cells infected with the IE2 60 and IE2 40 deletion mutants, however, exhibit decreased expression of selected viral genes at late times. In particular, expression of the viral DNA replication factor UL84 is affected by the deletion of IE2 40, and expression of the tegument protein pp65 (ppUL83) is affected by the deletion of both IE2 40 and IE2 60. IE2 60 and IE2 40 are also required for the production of normal levels of infectious virus. Finally, IE2 40 appears to function as a repressor of major immediate-early transcription in the infected cell. These results begin to define functions for the IE2 60- and IE2 40-kDa proteins and indicate that these products contribute both to the expression of selected viral genes and to the overall progression of the infection.

scholarly journals FAK regulates IL-33 expression by controlling chromatin accessibility at c-Jun motifs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Billie G. C. Griffith ◽  
Rosanna Upstill-Goddard ◽  
Holly Brunton ◽  
Graeme R. Grimes ◽  
Andrew V. Biankin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Focal Adhesions ◽  
Gene Promoter ◽  
Chromatin Accessibility ◽  
Dependent Manner ◽  
Rna Seq ◽  
Interleukin 33 ◽  
Control Gene Expression ◽  
Differential Gene

AbstractFocal adhesion kinase (FAK) localizes to focal adhesions and is overexpressed in many cancers. FAK can also translocate to the nucleus, where it binds to, and regulates, several transcription factors, including MBD2, p53 and IL-33, to control gene expression by unknown mechanisms. We have used ATAC-seq to reveal that FAK controls chromatin accessibility at a subset of regulated genes. Integration of ATAC-seq and RNA-seq data showed that FAK-dependent chromatin accessibility is linked to differential gene expression, including of the FAK-regulated cytokine and transcriptional regulator interleukin-33 (Il33), which controls anti-tumor immunity. Analysis of the accessibility peaks on the Il33 gene promoter/enhancer regions revealed sequences for several transcription factors, including ETS and AP-1 motifs, and we show that c-Jun, a component of AP-1, regulates Il33 gene expression by binding to its enhancer in a FAK kinase-dependent manner. This work provides the first demonstration that FAK controls transcription via chromatin accessibility, identifying a novel mechanism by which nuclear FAK regulates biologically important gene expression.

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