scholarly journals Exploring the Genetic Basis of Human Population Differences in DNA Methylation and their Causal Impact on Immune Gene Regulation

2018 ◽  
Author(s):  
Lucas T. Husquin ◽  
Maxime Rotival ◽  
Maud Fagny ◽  
Hélène Quach ◽  
Nora Zidane ◽  
...  

AbstractDNA methylation is influenced by both environmental and genetic factors and is increasingly thought to affect variation in complex traits and diseases. Yet, the extent of ancestry-related differences in DNA methylation, its genetic determinants, and their respective causal impact on immune gene regulation remain elusive. We report extensive population differences in DNA methylation between individuals of African and European descent — detected in primary monocytes that were used as a model of a major innate immunity cell type. Most of these differences (~70%) were driven by DNA sequence variants nearby CpG sites (meQTLs), which account for ~60% of the variance in DNA methylation. We also identify several master regulators of DNA methylation variation in trans, including a regulatory hub nearby the transcription factor-encoding CTCF gene, which contributes markedly to ancestry-related differences in DNA methylation. Furthermore, we establish that variation in DNA methylation is associated with varying gene expression levels following mostly, but not exclusively, a canonical model of negative associations, particularly in enhancer regions. Specifically, we find that DNA methylation highly correlates with transcriptional activity of 811 and 230 genes, at the basal state and upon immune stimulation, respectively. Finally, using a Bayesian approach, we estimate causal mediation effects of DNA methylation on gene expression in ~20% of the studied cases, indicating that DNA methylation can play an active role in immune gene regulation. Using a system-level approach, our study reveals substantial ancestry-related differences in DNA methylation and provides evidence for their causal impact on immune gene regulation.

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Lucas T. Husquin ◽  
Maxime Rotival ◽  
Maud Fagny ◽  
Hélène Quach ◽  
Nora Zidane ◽  
...  

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Maria Gutierrez-Arcelus ◽  
Tuuli Lappalainen ◽  
Stephen B Montgomery ◽  
Alfonso Buil ◽  
Halit Ongen ◽  
...  

DNA methylation is an essential epigenetic mark whose role in gene regulation and its dependency on genomic sequence and environment are not fully understood. In this study we provide novel insights into the mechanistic relationships between genetic variation, DNA methylation and transcriptome sequencing data in three different cell-types of the GenCord human population cohort. We find that the association between DNA methylation and gene expression variation among individuals are likely due to different mechanisms from those establishing methylation-expression patterns during differentiation. Furthermore, cell-type differential DNA methylation may delineate a platform in which local inter-individual changes may respond to or act in gene regulation. We show that unlike genetic regulatory variation, DNA methylation alone does not significantly drive allele specific expression. Finally, inferred mechanistic relationships using genetic variation as well as correlations with TF abundance reveal both a passive and active role of DNA methylation to regulatory interactions influencing gene expression.


2018 ◽  
Author(s):  
Eilis Hannon ◽  
Tyler J Gorrie-Stone ◽  
Melissa C Smart ◽  
Joe Burrage ◽  
Amanda Hughes ◽  
...  

ABSTRACTCharacterizing the complex relationship between genetic, epigenetic and transcriptomic variation has the potential to increase understanding about the mechanisms underpinning health and disease phenotypes. In this study, we describe the most comprehensive analysis of common genetic variation on DNA methylation (DNAm) to date, using the Illumina EPIC array to profile samples from the UK Household Longitudinal study. We identified 12,689,548 significant DNA methylation quantitative trait loci (mQTL) associations (P < 6.52x10-14) occurring between 2,907,234 genetic variants and 93,268 DNAm sites, including a large number not identified using previous DNAm-profiling methods. We demonstrate the utility of these data for interpreting the functional consequences of common genetic variation associated with > 60 human traits, using Summary data–based Mendelian Randomization (SMR) to identify 1,662 pleiotropic associations between 36 complex traits and 1,246 DNAm sites. We also use SMR to characterize the relationship between DNAm and gene expression, identifying 6,798 pleiotropic associations between 5,420 DNAm sites and the transcription of 1,702 genes. Our mQTL database and SMR results are available via a searchable online database (http://www.epigenomicslab.com/online-data-resources/) as a resource to the research community.


2021 ◽  
Author(s):  
Groves Dixon ◽  
Mikhail Matz

Abstract BackgroundAs human activity alters the planet, there is a pressing need to understand how organisms adapt to environmental change. Of growing interest in this area is the role of epigenetic modifications, such as DNA methylation, in tailoring gene expression to fit novel conditions. Here, we reanalyzed nine invertebrate (Anthozoa and Hexapoda) datasets to validate a key prediction of this hypothesis: changes in DNA methylation in response to some condition correlate with changes in gene expression. ResultsWhile we detected both differential methylation and differential expression, there was no simple relationship between these differences. ConclusionIf changes in DNA methylation regulate invertebrate transcription, the mechanism does not follow a simple linear relationship.


2021 ◽  
Author(s):  
Kurosh S Mehershahi ◽  
Swaine Chen

DNA methylation is a common epigenetic mark that influences transcriptional regulation, and therefore cellular phenotype, across all domains of life, extending also to bacterial virulence. Both orphan methyltransferases and those from restriction modification systems (RMSs) have been co-opted to regulate virulence epigenetically in many bacteria. However, the potential regulatory role of DNA methylation mediated by archetypal Type I systems in Escherichia coli has never been studied. We demonstrated that removal of DNA methylated mediated by three different Escherichia coli Type I RMSs in three distinct E. coli strains had no detectable effect on gene expression or growth in a screen of 1190 conditions. Additionally, deletion of the Type I RMS EcoUTI in UTI89, a prototypical cystitis strain of E. coli , which led to loss of methylation at >750 sites across the genome, had no detectable effect on virulence in a murine model of ascending urinary tract infection (UTI). Finally, introduction of two heterologous Type I RMSs into UTI89 also resulted in no detectable change in gene expression or growth phenotypes. These results stand in sharp contrast with many reports of RMSs regulating gene expression in other bacteria, leading us to propose the concept of “regulation avoidance” for these E. coli Type I RMSs. We hypothesize that regulation avoidance is a consequence of evolutionary adaptation of both the RMSs and the E. coli genome. Our results provide a clear and (currently) rare example of regulation avoidance for Type I RMSs in multiple strains of E. coli , further study of which may provide deeper insights into the evolution of gene regulation and horizontal gene transfer.


2009 ◽  
Vol 27 (5) ◽  
pp. 239-252 ◽  
Author(s):  
Jun-ichi Satoh ◽  
Hiroko Tabunoki ◽  
Kunimasa Arima

The pathogenesis of Alzheimer disease (AD) involves the complex interaction between genetic and environmental factors affecting multiple cellular pathways. Recent advances in systems biology provide a system-level understanding of AD by elucidating the genome-wide molecular interactions. By using KeyMolnet, a bioinformatics tool for analyzing molecular interactions on the curated knowledgebase, we characterized molecular network of 2,883 all stages of AD-related genes (ADGs) and 559 incipient AD-related genes (IADGs) identified by global gene expression profiling of the hippocampal CA1 region of AD brains in terms of significant clinical and pathological correlations (Blalock et al., Proc Natl Acad Sci USA 101: 2173-2178, 2004). By the common upstream search, KeyMolnet identified cAMP-response element-binding protein (CREB) as the principal transcription factor exhibiting the most significant relevance to molecular networks of both ADGs and IADGs. The CREB-regulated transcriptional network included upregulated and downregulated sets of ADGs and IADGs, suggesting an involvement of generalized deregulation of the CREB signaling pathway in the pathophysiology of AD, beginning at the early stage of the disease. To verify thein silicoobservationsin vivo, we conducted immunohistochemical studies of 11 AD and 13 age-matched control brains by using anti-phoshorylated CREB (pCREB) antibody. An abnormal accumulation of pCREB imunoreactivity was identified in granules of granulovacuolar degeneration (GVD) in the hippocampal neurons of AD brains. These observations suggest that aberrant CREB-mediated gene regulation serves as a molecular biomarker of AD-related pathological processes, and support the hypothesis that sequestration of pCREB in GVD granules is in part responsible for deregulation of CREB-mediated gene expression in AD hippocampus.


2019 ◽  
Vol 50 (6) ◽  
Author(s):  
Holly J. Kilvitis ◽  
Aaron W. Schrey ◽  
Alexandria K. Ragsdale ◽  
Alejandro Berrio ◽  
Steve M. Phelps ◽  
...  

2018 ◽  
Vol 200 (24) ◽  
Author(s):  
Timothy Casselli ◽  
Yvonne Tourand ◽  
Adam Scheidegger ◽  
William K. Arnold ◽  
Anna Proulx ◽  
...  

ABSTRACTProkaryote restriction modification (RM) systems serve to protect bacteria from potentially detrimental foreign DNA. Recent evidence suggests that DNA methylation by the methyltransferase (MTase) components of RM systems can also have effects on transcriptome profiles. The type strain of the causative agent of Lyme disease,Borrelia burgdorferiB31, possesses two RM systems withN6-methyladenosine (m6A) MTase activity, which are encoded by thebbe02gene located on linear plasmid lp25 andbbq67on lp56. The specific recognition and/or methylation sequences had not been identified for either of theseB. burgdorferiMTases, and it was not previously known whether these RM systems influence transcript levels. In the current study, single-molecule real-time sequencing was utilized to map genome-wide m6A sites and to identify consensus modified motifs in wild-typeB. burgdorferias well as MTase mutants lacking either thebbe02gene alone or bothbbe02andbbq67genes. Four novel conserved m6A motifs were identified and were fully attributable to the presence of specific MTases. Whole-genome transcriptome changes were observed in conjunction with the loss of MTase enzymes, indicating that DNA methylation by the RM systems has effects on gene expression. Genes with altered transcription in MTase mutants include those involved in vertebrate host colonization (e.g.,rpoSregulon) and acquisition by/transmission from the tick vector (e.g.,rrp1andpdeB). The results of this study provide a comprehensive view of the DNA methylation pattern inB. burgdorferi, and the accompanying gene expression profiles add to the emerging body of research on RM systems and gene regulation in bacteria.IMPORTANCELyme disease is the most prevalent vector-borne disease in North America and is classified by the Centers for Disease Control and Prevention (CDC) as an emerging infectious disease with an expanding geographical area of occurrence. Previous studies have shown that the causative bacterium,Borrelia burgdorferi, methylates its genome using restriction modification systems that enable the distinction from foreign DNA. Although much research has focused on the regulation of gene expression inB. burgdorferi, the effect of DNA methylation on gene regulation has not been evaluated. The current study characterizes the patterns of DNA methylation by restriction modification systems inB. burgdorferiand evaluates the resulting effects on gene regulation in this important pathogen.


2021 ◽  
Author(s):  
Groves Dixon ◽  
Mikhail V Matz

As human activity alters the planet, there is a pressing need to understand how organisms adapt to environmental change. Of growing interest in this area is the role of epigenetic modifications, such as DNA methylation, in tailoring gene expression to fit novel conditions. Here, we reanalyzed nine invertebrate (Anthozoa and Hexapoda) datasets to validate a key prediction of this hypothesis: changes in DNA methylation in response to some condition correlate with changes in gene expression. While we detected both differential methylation and differential expression, there was no simple relationship between these differences. Hence, if changes in DNA methylation regulate invertebrate transcription, the mechanism does not follow a simple linear relationship.


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