scholarly journals Alu repeats at the boundaries of regulatory elements shape the epigenetic environment of immune genes in T cells

2021 ◽  
Author(s):  
Mickael COSTALLAT ◽  
Christophe Rachez ◽  
Christian MUCHARDT
Keyword(s):  
Dna Methylation ◽  
T Cells ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Average Length ◽  
Boundary Function ◽  
Regulatory Elements ◽  
Immune Gene ◽  
Alu Elements ◽  
Immune Genes

Promoters and enhancers are sites of transcription initiation (TSSs) and carry active histone modifications, including H3K4me1, H3K4me3, and H3K27ac. Yet, the principles governing the boundaries of such regulatory elements are still poorly characterized. Alu elements are good candidates for a boundary function, being highly abundant in gene-rich regions, while essentially excluded from regulatory elements. Here, we show that the interval from the TSS to the first upstream Alu accommodates essentially all H3K4me3 marks, while excluding DNA methylation. In contrast, enhancer-enriched H3K4me1 and H3K27ac marks eventually cross the first-Alu limit, consistent with enhancer-annotation occasionally overlapping with Alu elements. Remarkably, the average length of TSS-to-first Alu intervals greatly varies in-between tissues, being longer in stem- and shorter in immune-cells. Shortest TSS-to-Alu intervals were observed at promoters active in T cells, particularly at immune genes, correlating with serendipitous RNA polymerase II transcription and accumulation of H3K4me1 signal at the first-Alu. At several T-cell first-Alus, the DNA methylation was further found to evolved with age, regressing from young to middle-aged, then recovering later in life. Thus, the first-Alu upstream of TSSs functions as a dynamic boundary for regulatory elements, initiating the upstream DNA-methylation landscape, while also participating in the recording of immune gene transcriptional events.

The Long Road to Understanding RNAPII Transcription Initiation and Related Syndromes

2021 ◽  
Vol 90 (1) ◽  
pp. 193-219
Author(s):  
Emmanuel Compe ◽  
Jean-Marc Egly
Keyword(s):  
Transcription Factors ◽  
Rna Polymerase Ii ◽  
Chromatin Remodeling ◽  
Transcription Initiation ◽  
Rna Synthesis ◽  
Regulatory Elements ◽  
Initiation Mechanism ◽  
Protein Coding ◽  
Core Promoters ◽  
General Transcription Factors

In eukaryotes, transcription of protein-coding genes requires the assembly at core promoters of a large preinitiation machinery containing RNA polymerase II (RNAPII) and general transcription factors (GTFs). Transcription is potentiated by regulatory elements called enhancers, which are recognized by specific DNA-binding transcription factors that recruit cofactors and convey, following chromatin remodeling, the activating cues to the preinitiation complex. This review summarizes nearly five decades of work on transcription initiation by describing the sequential recruitment of diverse molecular players including the GTFs, the Mediator complex, and DNA repair factors that support RNAPII to enable RNA synthesis. The elucidation of the transcription initiation mechanism has greatly benefited from the study of altered transcription components associated with human diseases that could be considered transcription syndromes.

scholarly journals Specific expression of the human CD4 gene in mature CD4+ CD8- and immature CD4+ CD8+ T cells and in macrophages of transgenic mice

1994 ◽  
Vol 14 (2) ◽  
pp. 1084-1094
Author(s):  
Z Hanna ◽  
C Simard ◽  
A Laperrière ◽  
P Jolicoeur
Keyword(s):  
T Cells ◽  
T Cell ◽  
Transgenic Mice ◽  
Cd8 T Cells ◽  
Transcription Initiation ◽  
Critical Role ◽  
Regulatory Elements ◽  
T Cell Subsets ◽  
Double Positive ◽  
Specific Expression

The CD4 protein plays a critical role in the development and function of the immune system. To gain more insight into the mechanism of expression of the human CD4 gene, we cloned 42.2 kbp of genomic sequences comprising the CD4 gene and its surrounding sequences. Studies with transgenic mice revealed that a 12.6-kbp fragment of the human CD4 gene (comprising 2.6 kbp of 5' sequences upstream of the transcription initiation site, the first two exons and introns, and part of exon 3) contains the sequences required to support the appropriate expression in murine mature CD4+ CD8- T cells and macrophages but not in immature double-positive CD4+ CD8+ T cells. Expression in CD4+ CD8+ T cells was found to require additional regulatory elements present in a T-cell enhancer fragment recently identified for the murine CD4 gene (S. Sawada and D. R. Littman, Mol. Cell. Biol. 11:5506-5515, 1991). These results suggest that expression of CD4 in mature and immature T-cell subsets may be controlled by distinct and independent regulatory elements. Alternatively, specific regulatory elements may control the expression of CD4 at different levels in mature and immature T-cell subsets. Our data also indicate that mouse macrophages contain the regulatory factors necessary to transcribe the human CD4 gene.

scholarly journals Identification the prognostic value of immune gene signature and infiltrating immune cells of esophageal cancer patients

2020 ◽  
Author(s):  
Lin Wang ◽  
Qian Wei ◽  
Ming Zhang ◽  
Lianze Chen ◽  
Zinan Li ◽  
...  
Keyword(s):  
T Cells ◽  
Esophageal Cancer ◽  
Signaling Pathway ◽  
Immune Cells ◽  
Roc Curves ◽  
Survival Outcome ◽  
Immune Gene ◽  
Prognostic Signature ◽  
Immune Genes ◽  
Validation Set

Abstract Background Esophageal cancer (ESCA) is one of the deadliest solid malignancies with worse survival in the world. The poor prognosis of ESCA is not only related to malignant cells, but also affected by the microenvironment. We aimed to establish prognostic signature consisting of immune genes to predict the survival outcome of patients and estimate the prognosis value of infiltrating immune cells in tumor microenvironment (TME). Methods Based on integrated analysis of gene expression profiling and immune gene database, differentially immune-related genes were filtered out. Then, stepwise Cox regression analysis was applied to identify survival related immune genes and construct prognosis signature. Functional enrichment analysis was performed to explore biology function. Kaplan-Meier (K-M) curves and receiver operating characteristic (ROC) curves were performed to validate the predictive effect of predictive signature. We also verified the clinical value of prognostic signature under the influence of different clinical parameters. For deeper analysis, we evaluated the correlation between prognosis signature and infiltrating immune cells by Tumor Immune Estimation Resource (TIMER) and CIBERSORT. Results Finally, we identified 303 differentially immune genes as candidate and constructed immune prognosis signature composed of six immune genes. Furthermore, we observed that the prognosis signature was enriched in cytokine-mediated signaling pathway, lymphocyte activation, immune effector process, cancer pathway, NF-kappa B signaling pathway. K-M survival curves showed that the prognosis signature indeed have good predictive ability in entire ESCA set ( P =0.003), validation set 1 ( P =0.008) and validation set 2 ( P =0.036). The area under the curve (AUC) of ROC curves validated the predictive accuracy of immune signature in three cohorts (AUC=0.757, 0.800 and 0.701), respectively. In addition, we identified the prognosis value of infiltrating-immune cells including activated memory CD4 T cells, T cells follicular helper cells and monocytes and provided a landscape of TME. Conclusions The results indicated that immune prognosis signature can be a novel biomarker to predict survival outcome, which can provide new targets for immunotherapy and individualized therapies in ESCA and open up a new prospect for improving the prognosis of ESCA patients in the era of immunotherapy.

scholarly journals Quantitative modelling predicts the impact of DNA methylation on RNA polymerase II traffic

2019 ◽  
Vol 116 (30) ◽  
pp. 14995-15000 ◽  
Author(s):  
Justyna Cholewa-Waclaw ◽  
Ruth Shah ◽  
Shaun Webb ◽  
Kashyap Chhatbar ◽  
Bernard Ramsahoye ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rett Syndrome ◽  
Transcription Initiation ◽  
Expression Patterns ◽  
Global Gene Expression ◽  
A Genome ◽  
The Impact

Patterns of gene expression are primarily determined by proteins that locally enhance or repress transcription. While many transcription factors target a restricted number of genes, others appear to modulate transcription levels globally. An example is MeCP2, an abundant methylated-DNA binding protein that is mutated in the neurological disorder Rett syndrome. Despite much research, the molecular mechanism by which MeCP2 regulates gene expression is not fully resolved. Here, we integrate quantitative, multidimensional experimental analysis and mathematical modeling to indicate that MeCP2 is a global transcriptional regulator whose binding to DNA creates “slow sites” in gene bodies. We hypothesize that waves of slowed-down RNA polymerase II formed behind these sites travel backward and indirectly affect initiation, reminiscent of defect-induced shockwaves in nonequilibrium physics transport models. This mechanism differs from conventional gene-regulation mechanisms, which often involve direct modulation of transcription initiation. Our findings point to a genome-wide function of DNA methylation that may account for the reversibility of Rett syndrome in mice. Moreover, our combined theoretical and experimental approach provides a general method for understanding how global gene-expression patterns are choreographed.

scholarly journals Epigenetic alterations in skin homing CD4+CLA+ T cells of atopic dermatitis patients

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Nathalie Acevedo ◽  
Rui Benfeitas ◽  
Shintaro Katayama ◽  
Sören Bruhn ◽  
Anna Andersson ◽  
...  
Keyword(s):  
Dna Methylation ◽  
T Cells ◽  
Atopic Dermatitis ◽  
Regulatory Elements ◽  
Upstream Region ◽  
Cytokine Signaling ◽  
Integrated Network ◽  
Molecular Alterations ◽  
Protein Ubiquitination ◽  
Skin Homing

Abstract T cells expressing the cutaneous lymphocyte antigen (CLA) mediate pathogenic inflammation in atopic dermatitis (AD). The molecular alterations contributing to their dysregulation remain unclear. With the aim to elucidate putative altered pathways in AD we profiled DNA methylation levels and miRNA expression in sorted T cell populations (CD4+, CD4+CD45RA+ naïve, CD4+CLA+, and CD8+) from adult AD patients and healthy controls (HC). Skin homing CD4+CLA+ T cells from AD patients showed significant differences in DNA methylation in 40 genes compared to HC (p < 0.05). Reduced DNA methylation levels in the upstream region of the interleukin-13 gene (IL13) in CD4+CLA+ T cells from AD patients correlated with increased IL13 mRNA expression in these cells. Sixteen miRNAs showed differential expression in CD4+CLA+ T cells from AD patients targeting genes in 202 biological processes (p < 0.05). An integrated network analysis of miRNAs and CpG sites identified two communities of strongly interconnected regulatory elements with strong antagonistic behaviours that recapitulated the differences between AD patients and HC. Functional analysis of the genes linked to these communities revealed their association with key cytokine signaling pathways, MAP kinase signaling and protein ubiquitination. Our findings support that epigenetic mechanisms play a role in the pathogenesis of AD by affecting inflammatory signaling molecules in skin homing CD4+CLA+ T cells and uncover putative molecules participating in AD pathways.

scholarly journals Specific expression of the human CD4 gene in mature CD4+ CD8- and immature CD4+ CD8+ T cells and in macrophages of transgenic mice.

1994 ◽  
Vol 14 (2) ◽  
pp. 1084-1094 ◽  
Author(s):  
Z Hanna ◽  
C Simard ◽  
A Laperrière ◽  
P Jolicoeur
Keyword(s):  
T Cells ◽  
T Cell ◽  
Transgenic Mice ◽  
Cd8 T Cells ◽  
Transcription Initiation ◽  
Critical Role ◽  
Regulatory Elements ◽  
T Cell Subsets ◽  
Double Positive ◽  
Specific Expression

The CD4 protein plays a critical role in the development and function of the immune system. To gain more insight into the mechanism of expression of the human CD4 gene, we cloned 42.2 kbp of genomic sequences comprising the CD4 gene and its surrounding sequences. Studies with transgenic mice revealed that a 12.6-kbp fragment of the human CD4 gene (comprising 2.6 kbp of 5' sequences upstream of the transcription initiation site, the first two exons and introns, and part of exon 3) contains the sequences required to support the appropriate expression in murine mature CD4+ CD8- T cells and macrophages but not in immature double-positive CD4+ CD8+ T cells. Expression in CD4+ CD8+ T cells was found to require additional regulatory elements present in a T-cell enhancer fragment recently identified for the murine CD4 gene (S. Sawada and D. R. Littman, Mol. Cell. Biol. 11:5506-5515, 1991). These results suggest that expression of CD4 in mature and immature T-cell subsets may be controlled by distinct and independent regulatory elements. Alternatively, specific regulatory elements may control the expression of CD4 at different levels in mature and immature T-cell subsets. Our data also indicate that mouse macrophages contain the regulatory factors necessary to transcribe the human CD4 gene.

scholarly journals Development of an Individualized Immune Prognostic Signature for Clear Cell Renal Cell Carcinoma through the Identification of Differential Immune Genes

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jianfeng Wang ◽  
Chaozhi Tang ◽  
Xiaowu Liu
Keyword(s):  
Renal Cell Carcinoma ◽  
T Cells ◽  
Cell Carcinoma ◽  
Renal Cell ◽  
Clear Cell ◽  
Immune Gene ◽  
Cell Renal Cell Carcinoma ◽  
Immune Genes ◽  
Tumor Microenvironments ◽  
Prognosis Model

Increasing evidence has shown that tumor microenvironments are an important feature in clear cell renal cell carcinoma (ccRCC) carcinogenesis and therapeutic efficacy. In this study, two subtypes of ccRCC, high- and low-immune groups, were identified based on the immune gene datasets, of which the differential immune genes were identified accordingly. Furthermore, we constructed a risk prognosis model using five immune genes, specifically, AQP9, KIAA1429, HAMP, CCL13, and CCL21. This model was highly predictive of ccRCC clinical characteristics and showed potential for use in immunotherapy. Furthermore, the five identified genes were highly correlated with the abundance of B cells, CD4 T cells, CD8 T cells, macrophages, neutrophils, and dendritic cells in the tumor microenvironments. Among them, AQP9, KIAA1429, and HAMP exhibited significant prognostic potential. These findings indicate that monitoring and operating tumor microenvironments are of great significance for ccRCC prognosis and precise immunotherapy.

scholarly journals A Four-Immune Gene Prognostic Risk Model for Colorectal Adenocarcinoma Based on the TCGA and Immport Data Sets

2020 ◽  
Author(s):  
Boyang Xu ◽  
Ziqi Peng ◽  
Yue An ◽  
Xue Yao ◽  
Mingjun Sun
Keyword(s):  
T Cells ◽  
Colorectal Adenocarcinoma ◽  
Immune Cell ◽  
Risk Model ◽  
The Cancer Genome Atlas ◽  
Differentially Expressed ◽  
Data Sets ◽  
Immune Gene ◽  
Immune Genes ◽  
Follicular Helper

Abstract BackgroundAs one of the hot spots in oncology field, immune research provides new ideas for the diagnosis and treatment of tumors. Different histological types of colorectal cancer are different. Adenocarcinoma, as the type with the highest proportion, has a high research value. This study aims to build an immune gene prognostic risk model for colorectal adenocarcinoma to improve the diagnosis and prognosis prediction of colorectal adenocarcinoma.MethodsThe differentially expressed immune genes could be obtained from the gene expression data downloaded from The Cancer Genome Atlas (TCGA) and the immune gene data downloaded from the ImmPort Database. Univariate COX and multivariate COX analyses were used to construct the immune gene prognostic risk model of and the clinical application potential of this model. The correlation between the model and the immune cells infiltration and the influence of each immune cell on the survival were analyzed.Results5975 differentially expressed genes were obtained, and 497 differentially expressed immune genes were selected by combining the information of immune genes. Among them, 36 immune genes were associated with prognosis, and 4 immune genes (THRB, IL1RL2, LGR6, LTB4R2) were included in the prognostic risk model of immune genes. Patients with higher Risk Score had shorter survival. Compared with gender, age and pathological stage, the model has better prediction potential. In addition, the model was correlated with Macrophages M0, Macrophages M1, T cells follicular helper and NK cells activated. Among them, T cells follicular helper and Macrophages M0 were related to the survival of patients.ConclusionWe developed a prognostic risk model containing four immune genes, THRB, IL1RL2, LGR6 and LTB4R2, which accurately described the prognosis of the patient, and affected the survival of patients by influencing the infiltration of Macrophages M0 and T cells follicular helper.

scholarly journals Ligand-induced native G-quadruplex stabilization impairs transcription initiation

2021 ◽  
Author(s):  
Conghui Li ◽  
Honghong Wang ◽  
Zhinang Yin ◽  
Pingping Fang ◽  
Ruijing Xiao ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Gene Transcription ◽  
Transcription Initiation ◽  
Regulatory Elements ◽  
Gene Promoters ◽  
Drug Induced ◽  
Transcriptional Regulatory Elements ◽  
Genome Wide ◽  
Self Association

G-quadruplexes (G4s) are noncanonical DNA secondary structures formed through the self-association of guanines, and G4s are distributed widely across the genome. G4 participates in multiple biological processes including gene transcription, and G4-targeted ligands serve as potential therapeutic agents for DNA-targeted therapies. However, genome-wide studies of the exact roles of G4s in transcriptional regulation are still lacking. Here, we establish a sensitive G4-CUT&Tag method for genome-wide profiling of native G4s with high resolution and specificity. We find that native G4 signals are cell type–specific and are associated with transcriptional regulatory elements carrying active epigenetic modifications. Drug-induced promoter-proximal RNA polymerase II pausing promotes nearby G4 formation. In contrast, G4 stabilization by G4-targeted ligands globally reduces RNA polymerase II occupancy at gene promoters as well as nascent RNA synthesis. Moreover, ligand-induced G4 stabilization modulates chromatin states and impedes transcription initiation via inhibition of general transcription factors loading to promoters. Together, our study reveals a reciprocal genome-wide regulation between native G4 dynamics and gene transcription, which will deepen our understanding of G4 biology toward therapeutically targeting G4s in human diseases.

scholarly journals WOMEN IN CANCER THEMATIC REVIEW: Diverse functions of DNA methylation: implications for prostate cancer and beyond

2016 ◽  
Vol 23 (11) ◽  
pp. T169-T178 ◽  
Author(s):  
Thomas J Sweet ◽  
Angela H Ting
Keyword(s):  
Prostate Cancer ◽  
Dna Methylation ◽  
Transcription Initiation ◽  
Alternative Polyadenylation ◽  
Regulatory Elements ◽  
Gene Promoters ◽  
Prostate Tumorigenesis ◽  
Cpg Dinucleotides ◽  
Molecular Features ◽  
Cancer Aggressiveness

Prostate cancer is one of the most common malignancies in men worldwide. Current clinical screening ensures that most prostate cancers are diagnosed while still organ confined, but disease outcome is highly variable. Thus, a better understanding of the molecular features contributing to prostate cancer aggressiveness is being sought. For many cancers, aberrant genome-wide patterns of cytosine DNA methylation in CpG dinucleotides distinguish tumor from normal tissue and contribute to disease progression by altering the transcriptome. In prostate cancer, recent genomic studies identified cancer and high grade-specific differential DNA methylation in gene promoters, gene bodies, gene 3′ ends and at distal regulatory elements. Using examples from developmental and disease systems, we will discuss how DNA methylation in each of these genomic contexts can contribute to transcriptome diversity by modulating transcription initiation, alternative transcription start site selection, alternative pre-mRNA splicing and alternative polyadenylation. Alternative transcripts from the same gene often exhibit altered protein-coding potential, translatability, stability and/or localization. All of these can have functional consequences in cells. In future work, it will be important to determine if DNA methylation abnormalities in prostate cancer modify the transcriptome through some or all of these mechanisms and if these DNA methylation-mediated transcriptome alterations impact prostate tumorigenesis and aggressiveness.

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