Correction: Brain Region-Specific Expression of MeCP2 Isoforms Correlates with DNA Methylation within Mecp2 Regulatory Elements
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PROVIDER: S-EPMC4077763 | biostudies-literature | 2014 Jan
REPOSITORIES: biostudies-literature
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Project description:MeCP2 is a critical epigenetic regulator in brain and its abnormal expression or compromised function leads to a spectrum of neurological disorders including Rett Syndrome and autism. Altered expression of the two MeCP2 isoforms, MeCP2E1 and MeCP2E2 has been implicated in neurological complications. However, expression, regulation and functions of the two isoforms are largely uncharacterized. Previously, we showed the role of MeCP2E1 in neuronal maturation and reported MeCP2E1 as the major protein isoform in the adult mouse brain, embryonic neurons and astrocytes. Recently, we showed that DNA methylation at the regulatory elements (REs) within the Mecp2 promoter and intron 1 impact the expression of Mecp2 isoforms in differentiating neural stem cells. This current study is aimed for a comparative analysis of temporal, regional and cell type-specific expression of MeCP2 isoforms in the developing and adult mouse brain. MeCP2E2 displayed a later expression onset than MeCP2E1 during mouse brain development. In the adult female and male brain hippocampus, both MeCP2 isoforms were detected in neurons, astrocytes and oligodendrocytes. Furthermore, MeCP2E1 expression was relatively uniform in different brain regions (olfactory bulb, striatum, cortex, hippocampus, thalamus, brainstem and cerebellum), whereas MeCP2E2 showed differential enrichment in these brain regions. Both MeCP2 isoforms showed relatively similar distribution in these brain regions, except for cerebellum. Lastly, a preferential correlation was observed between DNA methylation at specific CpG dinucleotides within the REs and Mecp2 isoform-specific expression in these brain regions. Taken together, we show that MeCP2 isoforms display differential expression patterns during brain development and in adult mouse brain regions. DNA methylation patterns at the Mecp2 REs may impact this differential expression of Mecp2/MeCP2 isoforms in brain regions. Our results significantly contribute towards characterizing the expression profiles of Mecp2/MeCP2 isoforms and thereby provide insights on the potential role of MeCP2 isoforms in the developing and adult brain.
| S-EPMC3940938 | biostudies-literature
Project description:BackgroundAberrant MeCP2 expression in brain is associated with neurodevelopmental disorders including autism. In the brain of stressed mouse and autistic human patients, reduced MeCP2 expression is correlated with Mecp2/MECP2 promoter hypermethylation. Altered expression of MeCP2 isoforms (MeCP2E1 and MeCP2E2) is associated with neurological disorders, highlighting the importance of proper regulation of both isoforms. While known regulatory elements (REs) within the MECP2/Mecp2 promoter and intron 1 are involved in MECP2/Mecp2 regulation, Mecp2 isoform-specific regulatory mechanisms are unknown. We hypothesized that DNA methylation at these REs may impact the expression of Mecp2 isoforms.MethodsWe used a previously characterized in vitro differentiating neural stem cell (NSC) system to investigate the interplay between Mecp2 isoform-specific expression and DNA methylation at the Mecp2 REs. We studied altered expression of Mecp2 isoforms, affected by global DNA demethylation and remethylation, induced by exposure and withdrawal of decitabine (5-Aza-2'-deoxycytidine). Further, we performed correlation analysis between DNA methylation at the Mecp2 REs and the expression of Mecp2 isoforms after decitabine exposure and withdrawal.ResultsAt different stages of NSC differentiation, Mecp2 isoforms showed reciprocal expression patterns associated with minor, but significant changes in DNA methylation at the Mecp2 REs. Decitabine treatment induced Mecp2e1/MeCP2E1 (but not Mecp2e2) expression at day (D) 2, associated with DNA demethylation at the Mecp2 REs. In contrast, decitabine withdrawal downregulated both Mecp2 isoforms to different extents at D8, without affecting DNA methylation at the Mecp2 REs. NSC cell fate commitment was minimally affected by decitabine under tested conditions. Expression of both isoforms negatively correlated with methylation at specific regions of the Mecp2 promoter, both at D2 and D8. The correlation between intron 1 methylation and Mecp2e1 (but not Mecp2e2) varied depending on the stage of NSC differentiation (D2: negative; D8: positive).ConclusionsOur results show the correlation between the expression of Mecp2 isoforms and DNA methylation in differentiating NSC, providing insights on the potential role of DNA methylation at the Mecp2 REs in Mecp2 isoform-specific expression. The ability of decitabine to induce Mecp2e1/MeCP2E1, but not Mecp2e2 suggests differential sensitivity of Mecp2 isoforms to decitabine and is important for future drug therapies for autism.
| S-EPMC3900258 | biostudies-literature
Project description:DNA methylation may regulate gene expression by restricting the access of transcription factors. We have previously demonstrated that GATA-1 regulates the transcription of the CCR3 gene by dynamically interacting with both positively and negatively acting GATA elements of high affinity binding in the proximal promoter region including exon 1. Exon 1 has three CpG sites, two of which are positioned at the negatively acting GATA elements. We hypothesized that the methylation of these two CpGs sites might preclude GATA-1 binding to the negatively acting GATA elements and, as a result, increase the availability of GATA-1 to the positively acting GATA element, thereby contributing to an increase in GATA-1-mediated transcription of the gene. To this end, we determined the methylation of the three CpG sites by bisulfate pyrosequencing in peripheral blood eosinophils, cord blood (CB)-derived eosinophils, PBMCs, and cell lines that vary in CCR3 mRNA expression. Our results demonstrated that methylation of CpG sites at the negatively acting GATA elements severely reduced GATA-1 binding and augmented transcription activity in vitro. In agreement, methylation of these CpG sites positively correlated with CCR3 mRNA expression in the primary cells and cell lines examined. Interestingly, methylation patterns of these three CpG sites in CB-derived eosinophils mostly resembled those in peripheral blood eosinophils. These results suggest that methylation of CpG sites at the GATA elements in the regulatory regions fine-tunes CCR3 transcription.
| S-EPMC3349909 | biostudies-other
Project description:Renin is responsible for initiating the enzymatic cascade that results in the production of angiotensin II, the major effector molecule of the renin-angiotensin system (RAS). Extensive information on the regulatory region of the renin gene has been derived by transient transfection studies in vitro, particularly using the As4.1 cell line. To verify key factors within the regulatory region of renin in vivo, homologous recombination was used to introduce a green fluorescent protein (GFP) cassette into exon one of the renin gene contained within a 240 kb bacterial artificial chromosome (BAC) to create a construct that has GFP expression controlled by the renin regulatory region (RenGFP BAC). Within the regulatory region of the RenGFP BAC construct we independently deleted the enhancer, as well as mutated the HOX-PBX site within the proximal promoter element. Transgenic lines were generated for each of these BAC constructs and GFP expression was analyzed throughout a spectrum of tissues positive for renin expression including the kidney, adrenal gland, gonadal artery, and submandibular gland. The results described within this manuscript support the interpretation that the renin enhancer is critical for regulating baseline expression where as the Hox/Pbx site is important for the tissue specificity of renin expression.
| S-EPMC2585016 | biostudies-literature
Project description:Mutations in MECP2, encoding methyl CpG binding protein 2 (MeCP2), cause most cases of Rett syndrome (RTT), an X-linked neurodevelopmental disorder. Both RTT and autism are "pervasive developmental disorders" and share a loss of social, cognitive and language skills and a gain in repetitive stereotyped behavior, following apparently normal perinatal development. Although MECP2 coding mutations are a rare cause of autism, MeCP2 expression defects were previously found in autism brain. To further study the role of MeCP2 in autism spectrum disorders (ASDs), we determined the frequency of MeCP2 expression defects in brain samples from autism and other ASDs. We also tested the hypotheses that MECP2 promoter mutations or aberrant promoter methylation correlate with reduced expression in cases of idiopathic autism. MeCP2 immunofluorescence in autism and other neurodevelopmental disorders was quantified by laser scanning cytometry and compared with control postmortem cerebral cortex samples on a large tissue microarray. A significant reduction in MeCP2 expression compared to age-matched controls was found in 11/14 autism (79%), 9/9 RTT (100%), 4/4 Angelman syndrome (100%), 3/4 Prader-Willi syndrome (75%), 3/5 Down syndrome (60%), and 2/2 attention deficit hyperactivity disorder (100%) frontal cortex samples. One autism female was heterozygous for a rare MECP2 promoter variant that correlated with reduced MeCP2 expression. A more frequent occurrence was significantly increased MECP2 promoter methylation in autism male frontal cortex compared to controls. Furthermore, percent promoter methylation of MECP2 significantly correlated with reduced MeCP2 protein expression. These results suggest that both genetic and epigenetic defects lead to reduced MeCP2 expression and may be important in the complex etiology of autism.
| S-EPMC1866172 | biostudies-literature
Project description:Background5-Hydroxymethylcytosine (5hmC) is an oxidation product of 5-methylcytosine (5mC), and adjacent CpG sites in mammalian genome can be co-methylated and co-hydroxymethylated due to the processivity of DNMT and TET enzymes.ResultsWe applied TAB-seq and oxBS-seq to selectively detect 5hmC and 5mC at base resolution in the mouse cortex, olfactory bulb and cerebellum tissues. We found that majority of the called 5hmC CpG sites frequently have 5mC modification simultaneously and are enriched in gene body regions of neuron development-related genes in brain tissues. Strikingly, by a systematic search of regions that show highly coordinated methylation and hydroxymethylation (MHBs and hMHBs), we found that MHBs significantly overlapped with hMHBs in gene body regions. Moreover, using a metric called methylation haplotype load, we defined a subset of 1361 tissue-specific MHBs and 3818 shared MHBs. Shared MHBs with low MHL correspond with developmental enhancers, and tissue-specific MHBs resemble the regulatory elements for tissue identity.ConclusionsOur results provide new insights into the role of coordinately oxidized 5mC to 5hmC as distal regulatory elements may involve in regulating tissue identity.
| S-EPMC6311040 | biostudies-literature
Project description:Methyl CpG Binding Protein 2 (MeCP2) is an important epigenetic factor in the brain. MeCP2 expression is affected by different environmental insults including alcohol exposure. Accumulating evidence supports the role of aberrant MeCP2 expression in ethanol exposure-induced neurological symptoms. However, the underlying molecular mechanisms of ethanol-induced MeCP2 deregulation remain elusive. To study the effect of ethanol on Mecp2/MeCP2 expression during neurodifferentiation, we established an in vitro model of ethanol exposure, using differentiating embryonic brain-derived neural stem cells (NSC). Previously, we demonstrated the impact of DNA methylation at the Mecp2 regulatory elements (REs) on Mecp2/MeCP2 expression in vitro and in vivo. Here, we studied whether altered DNA methylation at these REs is associated with the Mecp2/MeCP2 misexpression induced by ethanol. Binge-like and continuous ethanol exposure upregulated Mecp2/MeCP2, while ethanol withdrawal downregulated its expression. DNA methylation analysis by methylated DNA immunoprecipitation indicated that increased 5-hydroxymethylcytosine (5hmC) and decreased 5-methylcytosine (5mC) enrichment at specific REs were associated with upregulated Mecp2/MeCP2 following continuous ethanol exposure. The reduced Mecp2/MeCP2 expression upon ethanol withdrawal was associated with reduced 5hmC and increased 5mC enrichment at these REs. Moreover, ethanol altered global DNA methylation (5mC and 5hmC). Under the tested conditions, ethanol had minimal effects on NSC cell fate commitment, but caused changes in neuronal morphology and glial cell size. Taken together, our data represent an epigenetic mechanism for ethanol-mediated misexpression of Mecp2/MeCP2 in differentiating embryonic brain cells. We also show the potential role of DNA methylation and MeCP2 in alcohol-related neurological disorders, specifically Fetal Alcohol Spectrum Disorders.
| S-EPMC5798977 | biostudies-literature
Project description:BackgroundThe brain, spinal cord, and neural retina comprise the central nervous system (CNS) of vertebrates. Understanding the regulatory mechanisms that underlie the enormous cell-type diversity of the CNS is a significant challenge. Whole-genome mapping of DNase I-hypersensitive sites (DHSs) has been used to identify cis-regulatory elements in many tissues. We have applied this approach to the mouse CNS, including developing and mature neural retina, whole brain, and two well-characterized brain regions, the cerebellum and the cerebral cortex.ResultsFor the various regions and developmental stages of the CNS that we analyzed, there were approximately the same number of DHSs; however, there were many DHSs unique to each CNS region and developmental stage. Many of the DHSs are likely to mark enhancers that are specific to the specific CNS region and developmental stage. We validated the DNase I mapping approach for identification of CNS enhancers using the existing VISTA Browser database and with in vivo and in vitro electroporation of the retina. Analysis of transcription factor consensus sites within the DHSs shows distinct region-specific profiles of transcriptional regulators particular to each region. Clustering developmentally dynamic DHSs in the retina revealed enrichment of developmental stage-specific transcriptional regulators. Additionally, we found reporter gene activity in the retina driven from several previously uncharacterized regulatory elements surrounding the neurodevelopmental gene Otx2. Identification of DHSs shared between mouse and human showed region-specific differences in the evolution of cis-regulatory elements.ConclusionsOverall, our results demonstrate the potential of genome-wide DNase I mapping to cis-regulatory questions regarding the regional diversity within the CNS. These data represent an extensive catalogue of potential cis-regulatory elements within the CNS that display region and temporal specificity, as well as a set of DHSs common to CNS tissues. Further examination of evolutionary conservation of DHSs between CNS regions and different species may reveal important cis-regulatory elements in the evolution of the mammalian CNS.
| S-EPMC4429822 | biostudies-literature
Project description:DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system.
| S-EPMC4460470 | biostudies-other
Project description:OBJECTIVE:The pathogenesis of endometriosis is still mysterious, being retrograde menstruation and coelomic metaplasia the most accepted hypotheses. Recently, it has been proposed that endometriosis is caused by fine-tuning alterations of the female genital system development during the foetal life and that in utero exposition to endocrine disruptors can be one of the factors causing the disease, possibly acting on the methylation status of the genome. In this study, we have evaluated the methylation status of HOXA10 gene regulation regions in a cohort of 22 endometriosis patients respect to a control group of 6 healthy women. RESULTS:The methylation study was carried out on three CpG islands, previously described hypermethylated in the endometrium of endometriosis patients and include 22 CpG sites, 21 CpG sites and 10 CpG sites, respectively identified through the online platform MethPrimer. The analysis did not find significant differences between patients with endometriosis and healthy control individuals. These results confirm previous studies on genome wide methylation analysis in endometriosis patients. Therefore, other epigenetically altered genes should be considered more related to the pathogenesis of endometriosis.
| S-EPMC6182800 | biostudies-literature