scholarly journals Childhood-onset dystonia-causing KMT2B variants result in a distinctive genomic hypermethylation profile

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Andrea Ciolfi ◽  
Aidin Foroutan ◽  
Alessandro Capuano ◽  
Lucia Pedace ◽  
Lorena Travaglini ◽  
...  

Abstract Background Dystonia is a clinically and genetically heterogeneous movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements and/or postures. Heterozygous variants in lysine methyltransferase 2B (KMT2B), encoding a histone H3 methyltransferase, have been associated with a childhood-onset, progressive and complex form of dystonia (dystonia 28, DYT28). Since 2016, more than one hundred rare KMT2B variants have been reported, including frameshift, nonsense, splice site, missense and other in-frame changes, many having an uncertain clinical impact. Results We characterize the genome-wide peripheral blood DNA methylation profiles of a cohort of 18 patients with pathogenic and unclassified KMT2B variants. We resolve the “episignature” associated with KMT2B haploinsufficiency, proving that this approach is robust in diagnosing clinically unsolved cases, properly classifying them with respect to other partially overlapping dystonic phenotypes, other rare neurodevelopmental disorders and healthy controls. Notably, defective KMT2B function in DYT28 causes a non-random DNA hypermethylation across the genome, selectively involving promoters and other regulatory regions positively controlling gene expression. Conclusions We demonstrate a distinctive DNA hypermethylation pattern associated with DYT28, provide an epigenetic signature for this disorder enabling accurate diagnosis and reclassification of ambiguous genetic findings and suggest potential therapeutic approaches.

2020 ◽  
Vol 11 (11) ◽  
Author(s):  
Jing-dong Zhou ◽  
Ting-juan Zhang ◽  
Zi-jun Xu ◽  
Zhao-qun Deng ◽  
Yu Gu ◽  
...  

AbstractThe potential mechanism of myelodysplastic syndromes (MDS) progressing to acute myeloid leukemia (AML) remains poorly elucidated. It has been proved that epigenetic alterations play crucial roles in the pathogenesis of cancer progression including MDS. However, fewer studies explored the whole-genome methylation alterations during MDS progression. Reduced representation bisulfite sequencing was conducted in four paired MDS/secondary AML (MDS/sAML) patients and intended to explore the underlying methylation-associated epigenetic drivers in MDS progression. In four paired MDS/sAML patients, cases at sAML stage exhibited significantly increased methylation level as compared with the matched MDS stage. A total of 1090 differentially methylated fragments (DMFs) (441 hypermethylated and 649 hypomethylated) were identified involving in MDS pathogenesis, whereas 103 DMFs (96 hypermethylated and 7 hypomethylated) were involved in MDS progression. Targeted bisulfite sequencing further identified that aberrant GFRA1, IRX1, NPY, and ZNF300 methylation were frequent events in an additional group of de novo MDS and AML patients, of which only ZNF300 methylation was associated with ZNF300 expression. Subsequently, ZNF300 hypermethylation in larger cohorts of de novo MDS and AML patients was confirmed by real-time quantitative methylation-specific PCR. It was illustrated that ZNF300 methylation could act as a potential biomarker for the diagnosis and prognosis in MDS and AML patients. Functional experiments demonstrated the anti-proliferative and pro-apoptotic role of ZNF300 overexpression in MDS-derived AML cell-line SKM-1. Collectively, genome-wide DNA hypermethylation were frequent events during MDS progression. Among these changes, ZNF300 methylation, a regulator of ZNF300 expression, acted as an epigenetic driver in MDS progression. These findings provided a theoretical basis for the usage of demethylation drugs in MDS patients against disease progression.


PLoS ONE ◽  
2016 ◽  
Vol 11 (11) ◽  
pp. e0166438 ◽  
Author(s):  
Brian Egan ◽  
Chih-Chi Yuan ◽  
Madeleine Lisa Craske ◽  
Paul Labhart ◽  
Gulfem D. Guler ◽  
...  

2020 ◽  
Vol 7 (10) ◽  
pp. 2077
Author(s):  
Sai Chandar Dudipala ◽  
Naveen Reddy Cheruku ◽  
Krishna Chaithanya Battu

Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous group of neurological disorders that are characterized by progressive spasticity of the lower extremities. It can present as pure form or complex form. It can be present from infancy to adulthood, but majority in adult population. Childhood onset HSP must be differentiated from common conditions like cerebral palsy, neurodegenerative disorders and metabolic disorders. Many patients with pediatric HSP are mistakenly diagnosed with cerebral palsy. In children with spastic paraplegia in whom no acquired cause identified, HSP should be considered. Here we diagnosed a 6-year-old boy with HSP who presented with progressive spastic paraplegia, intellectual disability, seizures, joint contractures and cataract. His genetic study revealed exonic deletion of endoplasmic reticulum lipid raft-associated protein gene, which is associated with complicated Autosomal recessive HSP 18 (SPG18). HSP 18 was rarely described in literature.


2017 ◽  
Author(s):  
Cristina Cruz ◽  
Monica Della Rosa ◽  
Christel Krueger ◽  
Qian Gao ◽  
Lucy Field ◽  
...  

AbstractTranscription of protein coding genes is accompanied by recruitment of COMPASS to promoter-proximal chromatin, which deposits di- and tri-methylation on histone H3 lysine 4 (H3K4) to form H3K4me2 and H3K4me3. Here we determine the importance of COMPASS in maintaining gene expression across lifespan in budding yeast. We find that COMPASS mutations dramatically reduce replicative lifespan and cause widespread gene expression defects. Known repressive functions of H3K4me2 are progressively lost with age, while hundreds of genes become dependent on H3K4me3 for full expression. Induction of these H3K4me3 dependent genes is also impacted in young cells lacking COMPASS components including the H3K4me3-specific factor Spp1. Remarkably, the genome-wide occurrence of H3K4me3 is progressively reduced with age despite widespread transcriptional induction, minimising the normal positive correlation between promoter H3K4me3 and gene expression. Our results provide clear evidence that H3K4me3 is required to attain normal expression levels of many genes across organismal lifespan.


DNA Research ◽  
2018 ◽  
Vol 25 (5) ◽  
pp. 511-520 ◽  
Author(s):  
Satoshi Takahashi ◽  
Kenji Osabe ◽  
Naoki Fukushima ◽  
Shohei Takuno ◽  
Naomi Miyaji ◽  
...  

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Jing Shen ◽  
Shuang Wang ◽  
Abby B. Siegel ◽  
Helen Remotti ◽  
Qiao Wang ◽  
...  

Background.Previous studies, including ours, have examined the regulation of microRNAs (miRNAs) by DNA methylation, but whether this regulation occurs at a genome-wide level in hepatocellular carcinoma (HCC) is unclear.Subjects/Methods.Using a two-phase study design, we conducted genome-wide screening for DNA methylation and miRNA expression to explore the potential role of methylation alterations in miRNAs regulation.Results.We found that expressions of 25 miRNAs were statistically significantly different between tumor and nontumor tissues and perfectly differentiated HCC tumor from nontumor. Six miRNAs were overexpressed, and 19 were repressed in tumors. Among 133 miRNAs with inverse correlations between methylation and expression, 8 miRNAs (6%) showed statistically significant differences in expression between tumor and nontumor tissues. Six miRNAs were validated in 56 additional paired HCC tissues, and significant inverse correlations were observed for miR-125b and miR-199a, which is consistent with the inactive chromatin pattern found in HepG2 cells.Conclusion.These data suggest that the expressions of miR-125b and miR-199a are dramatically regulated by DNA hypermethylation that plays a key role in hepatocarcinogenesis.


Author(s):  
Sergio Raez-Villanueva ◽  
Amrita Debnath ◽  
Daniel B. Hardy ◽  
Alison C. Holloway

Abstract Prenatal exposure to nicotine, tobacco’s major addictive constituent, has been shown to reduce birth weight and increases apoptosis, oxidative stress, and mitochondrial dysfunction in the postnatal pancreas. Given that upregulated levels of the pro-oxidative adapter protein p66shc is observed in growth-restricted offspring and is linked to beta-cell apoptosis, the goal of this study was to investigate whether alterations in p66shc expression underlie the pancreatic deficits in nicotine-exposed offspring. Maternal administration of nicotine in rats increased p66shc expression in the neonatal pancreas. Similarly, nicotine treatment augmented p66shc expression in INS-1E pancreatic beta cells. Increased p66shc expression was also associated with decreased histone H3 lysine 9 methylation. Finally, nicotine increased the expression of Kdm4c, a key histone lysine demethylase, and decreased Suv39h1, a critical histone lysine methyltransferase. Collectively, these results suggest that upregulation of p66shc through posttranslational histone modifications may underlie the reported adverse outcomes of nicotine exposure on pancreatic function.


Genetics ◽  
2020 ◽  
Vol 215 (3) ◽  
pp. 569-578
Author(s):  
William K. Storck ◽  
Sabrina Z. Abdulla ◽  
Michael R. Rountree ◽  
Vincent T. Bicocca ◽  
Eric U. Selker

In chromatin, nucleosomes are composed of ∼146 bp of DNA wrapped around a histone octamer, and are highly dynamic structures subject to remodeling and exchange. Histone turnover has previously been implicated in various processes including the regulation of chromatin accessibility, segregation of chromatin domains, and dilution of histone marks. Histones in different chromatin environments may turnover at different rates, possibly with functional consequences. Neurospora crassa sports a chromatin environment that is more similar to that of higher eukaryotes than yeasts, which have been utilized in the past to explore histone exchange. We constructed a simple light-inducible system to profile histone exchange in N. crassa on a 3xFLAG-tagged histone H3 under the control of the rapidly inducible vvd promoter. After induction with blue light, incorporation of tagged H3 into chromatin occurred within 20 min. Previous studies of histone turnover involved considerably longer incubation periods and relied on a potentially disruptive change of medium for induction. We used this reporter to explore replication-independent histone turnover at genes and examine changes in histone turnover at heterochromatin domains in different heterochromatin mutant strains. In euchromatin, H3-3xFLAG patterns were almost indistinguishable from that observed in wild-type in all mutant backgrounds tested, suggesting that loss of heterochromatin machinery has little effect on histone turnover in euchromatin. However, turnover at heterochromatin domains increased with loss of trimethylation of lysine 9 of histone H3 or HP1, but did not depend on DNA methylation. Our reporter strain provides a simple yet powerful tool to assess histone exchange across multiple chromatin contexts.


mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Robert Jordan Price ◽  
Esther Weindling ◽  
Judith Berman ◽  
Alessia Buscaino

ABSTRACT Eukaryotic genomes are packaged into chromatin structures that play pivotal roles in regulating all DNA-associated processes. Histone posttranslational modifications modulate chromatin structure and function, leading to rapid regulation of gene expression and genome stability, key steps in environmental adaptation. Candida albicans, a prevalent fungal pathogen in humans, can rapidly adapt and thrive in diverse host niches. The contribution of chromatin to C. albicans biology is largely unexplored. Here, we generated the first comprehensive chromatin profile of histone modifications (histone H3 trimethylated on lysine 4 [H3K4me3], histone H3 acetylated on lysine 9 [H3K9Ac], acetylated lysine 16 on histone H4 [H4K16Ac], and γH2A) across the C. albicans genome and investigated its relationship to gene expression by harnessing genome-wide sequencing approaches. We demonstrated that gene-rich nonrepetitive regions are packaged into canonical euchromatin in association with histone modifications that mirror their transcriptional activity. In contrast, repetitive regions are assembled into distinct chromatin states; subtelomeric regions and the ribosomal DNA (rDNA) locus are assembled into heterochromatin, while major repeat sequences and transposons are packaged in chromatin that bears features of euchromatin and heterochromatin. Genome-wide mapping of γH2A, a marker of genome instability, identified potential recombination-prone genomic loci. Finally, we present the first quantitative chromatin profiling in C. albicans to delineate the role of the chromatin modifiers Sir2 and Set1 in controlling chromatin structure and gene expression. This report presents the first genome-wide chromatin profiling of histone modifications associated with the C. albicans genome. These epigenomic maps provide an invaluable resource to understand the contribution of chromatin to C. albicans biology and identify aspects of C. albicans chromatin organization that differ from that of other yeasts. IMPORTANCE The fungus Candida albicans is an opportunistic pathogen that normally lives on the human body without causing any harm. However, C. albicans is also a dangerous pathogen responsible for millions of infections annually. C. albicans is such a successful pathogen because it can adapt to and thrive in different environments. Chemical modifications of chromatin, the structure that packages DNA into cells, can allow environmental adaptation by regulating gene expression and genome organization. Surprisingly, the contribution of chromatin modification to C. albicans biology is still largely unknown. For the first time, we analyzed C. albicans chromatin modifications on a genome-wide basis. We demonstrate that specific chromatin states are associated with distinct regions of the C. albicans genome and identify the roles of the chromatin modifiers Sir2 and Set1 in shaping C. albicans chromatin and gene expression.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ieva Rauluseviciute ◽  
Finn Drabløs ◽  
Morten Beck Rye

Abstract Background Prostate cancer (PCa) has the highest incidence rates of cancers in men in western countries. Unlike several other types of cancer, PCa has few genetic drivers, which has led researchers to look for additional epigenetic and transcriptomic contributors to PCa development and progression. Especially datasets on DNA methylation, the most commonly studied epigenetic marker, have recently been measured and analysed in several PCa patient cohorts. DNA methylation is most commonly associated with downregulation of gene expression. However, positive associations of DNA methylation to gene expression have also been reported, suggesting a more diverse mechanism of epigenetic regulation. Such additional complexity could have important implications for understanding prostate cancer development but has not been studied at a genome-wide scale. Results In this study, we have compared three sets of genome-wide single-site DNA methylation data from 870 PCa and normal tissue samples with multi-cohort gene expression data from 1117 samples, including 532 samples where DNA methylation and gene expression have been measured on the exact same samples. Genes were classified according to their corresponding methylation and expression profiles. A large group of hypermethylated genes was robustly associated with increased gene expression (UPUP group) in all three methylation datasets. These genes demonstrated distinct patterns of correlation between DNA methylation and gene expression compared to the genes showing the canonical negative association between methylation and expression (UPDOWN group). This indicates a more diversified role of DNA methylation in regulating gene expression than previously appreciated. Moreover, UPUP and UPDOWN genes were associated with different compartments — UPUP genes were related to the structures in nucleus, while UPDOWN genes were linked to extracellular features. Conclusion We identified a robust association between hypermethylation and upregulation of gene expression when comparing samples from prostate cancer and normal tissue. These results challenge the classical view where DNA methylation is always associated with suppression of gene expression, which underlines the importance of considering corresponding expression data when assessing the downstream regulatory effect of DNA methylation.


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