Similar Datasets
Project description:DNA methylation is a common mechanism regulating monoallelic expression of different genes, including imprinted genes. How age-induced alterations of methylation levels vary across alleles and impact on monoallelic expression is unknown. In the brain, this phenomenon may contribute mechanistically to neuronal dysfunction and disease. In order to investigate the allele specific transcriptional and epigenetic signatures of aging, we used key brain areas, hippocampus and cerebellum, of juvenile and old hybrid mice obtained from BL6×CAST/EiJ (CAST) reciprocal crosses. We set out to explore whether epigenetic drift affects global DNA methylation machinery by investigating 5- methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) levels. Mass spectrometry analysis showed a significant increase of 5hmC levels in hippocampus of old mice, but this was not accompanied by measurable differences in methylating and demethylating enzymes. The expression of several repetitive elements (LINEs, SINEs, IAP) was also analysed, strictly dependent on 5mC and 5hmC levels, and reporting a reduction of the intracisternal A-particle (IAP) retrotransposons in HCP of old mice. We uncovered the allelic-specific DNA methylation profile of aging using genomic imprinting as a read-out by IMPLICON and allelic expression by RNA sequencing. Here, imprinting is not substantially changed during aging, not affecting their normal monoallelic expression. This work provides the first epigenetic and transcriptional landscape of aging with allelic resolution and confirms that genomic imprinting is a stable epigenetic phenomenon across the whole lifespan.
2024-07-15 | GSE232546 | GEO
Project description:DNA methylation is a common mechanism regulating monoallelic expression of different genes, including imprinted genes. How age-induced alterations of methylation levels vary across alleles and impact on monoallelic expression is unknown. In the brain, this phenomenon may contribute mechanistically to neuronal dysfunction and disease. In order to investigate the allele-specific transcriptional and epigenetic signatures of aging, we used key brain areas, hippocampus and cerebellum, of juvenile and old hybrid mice obtained from BL6×CAST reciprocal crosses. We set out to explore whether epigenetic drift affects global DNA methylation machinery by investigating 5- methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) levels. Mass spectrometry analysis showed a significant increase of 5hmC levels in hippocampus of old mice, but this was not accompanied by measurable differences in methylating or demethylating enzymes. The expression of several repetitive elements (LINEs, SINEs, IAP) was also analysed with a reduction of the intracisternal A-particle (IAP) retrotransposons seen in HCP of old mice. We uncovered the allelic-specific DNA methylation profile of aging using genomic imprinting as a read-out by IMPLICON and allelic-expression by RNA sequencing. Here, imprinting is not substantially changed during aging, not affecting their normal monoallelic expression. This work provides the first epigenetic and transcriptional landscape of aging with allelic resolution and confirms that genomic imprinting is a stable epigenetic phenomenon across the whole lifespan.
2024-07-15 | GSE232547 | GEO
Project description:There is increasing evidence that genomic imprinting, a process by which certain genes are expressed in a parent-of-origin-specific manner, can influence neurogenetic and psychiatric manifestations. While some data suggest possible imprinting effects of the X chromosome on physical and cognitive characteristics in humans, there is no compelling evidence that X-linked imprinting affects brain morphology. To address this issue, we investigated regional cortical volume, thickness, and surface area in 27 healthy controls and 40 prepubescent girls with Turner syndrome (TS), a condition caused by the absence of one X chromosome. Of the young girls with TS, 23 inherited their X chromosome from their mother (X(m)) and 17 from their father (X(p)). Our results confirm the existence of significant differences in brain morphology between girls with TS and controls, and reveal the presence of a putative imprinting effect among the TS groups: girls with X(p) demonstrated thicker cortex than those with X(m) in the temporal regions bilaterally, while X(m) individuals showed bilateral enlargement of gray matter volume in the superior frontal regions compared with X(p). These data suggest the existence of imprinting effects of the X chromosome that influence both cortical thickness and volume during early brain development, and help to explain variability in cognitive and behavioral manifestations of TS with regard to the parental origin of the X chromosome.
| S-EPMC3696011 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2019-06-17 | GSE119607 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2013-12-02 | E-GEOD-49764 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below.
2019-12-08 | GSE131784 | GEO
Project description:The X chromosome is known to play an important role in many sex-specific diseases. However, only a few single-nucleotide polymorphisms on the X chromosome have been found to be associated with diseases. Compared to the autosomes, conducting association tests on the X chromosome is more intractable due to the difference in the number of X chromosomes between females and males. On the other hand, X-chromosome inactivation takes place in female mammals, which is a phenomenon in which the expression of one copy of two X chromosomes in females is silenced in order to achieve the same gene expression level as that in males. In addition, imprinting effects may be related to certain diseases. Currently, there are some existing approaches taking X-chromosome inactivation into account when testing for associations on the X chromosome. However, none of them allows for imprinting effects. Therefore, in this paper, we propose a robust test, ZXCII, which accounts for both X-chromosome inactivation and imprinting effects without requiring specifying the genetic models in advance. Simulation studies are conducted in order to investigate the validity and performance of ZXCII under various scenarios of different parameter values. The simulation results show that ZXCII controls the type I error rate well when there is no association. Furthermore, with regards to power, ZXCII is robust in all of the situations considered and generally outperforms most of the existing methods in the presence of imprinting effects, especially under complete imprinting effects.
| S-EPMC7132553 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2013-12-02 | GSE49764 | GEO
Project description:BACKGROUND: hiPSCs are generated through epigenetic reprogramming of somatic tissue. Genomic imprinting is an epigenetic phenomenon through which monoallelic gene expression is regulated in a parent-of-origin-specific manner. Reprogramming relies on the successful erasure of marks of differentiation while maintaining those required for genomic imprinting. Loss of imprinting (LOI), which occurs in many types of malignant tumors, would hinder the clinical application of hiPSCs. RESULTS: We examined the imprinting status, expression levels and DNA methylation status of eight imprinted genes in five independently generated hiPSCs. We found a low frequency of LOI in some lines. Where LOI was identified in an early passage cell line, we found that this was maintained through subsequent passages of the cells. Just as normal imprints are maintained in long-term culture, this work suggests that abnormal imprints are also stable in culture. CONCLUSIONS: Analysis of genomic imprints in hiPSCs is a necessary safety step in regenerative medicine, with relevance both to the differentiation potential of these stem cells and also their potential tumorigenic properties.
| S-EPMC3751563 | biostudies-literature
Project description:During X chromosome inactivation (XCI), the inactive X chromosome (Xi) is recruited to the nuclear lamina at the nuclear periphery. Beside X chromosome reactivation resulting in a highly penetrant aging-like hematopoietic malignancy, little is known about XCI in aged hematopoietic stem cells (HSCs). Here, we demonstrate that LaminA/C defines a distinct repressive nuclear compartment for XCI in young HSCs, and its reduction in aged HSCs correlates with an impairment in the overall control of XCI. Integrated omics analyses reveal higher variation in gene expression, global hypomethylation, and significantly increased chromatin accessibility on the X chromosome (Chr X) in aged HSCs. In summary, our data support the role of LaminA/C in the establishment of a special repressive compartment for XCI in HSCs, which is impaired upon aging.
| S-EPMC8072063 | biostudies-literature