scholarly journals Genomic imprinting in mouse blastocysts is predominantly associated with H3K27me3

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Laura Santini ◽  
Florian Halbritter ◽  
Fabian Titz-Teixeira ◽  
Toru Suzuki ◽  
Maki Asami ◽  
...  

AbstractIn mammalian genomes, differentially methylated regions (DMRs) and histone marks including trimethylation of histone 3 lysine 27 (H3K27me3) at imprinted genes are asymmetrically inherited to control parentally-biased gene expression. However, neither parent-of-origin-specific transcription nor imprints have been comprehensively mapped at the blastocyst stage of preimplantation development. Here, we address this by integrating transcriptomic and epigenomic approaches in mouse preimplantation embryos. We find that seventy-one genes exhibit previously unreported parent-of-origin-specific expression in blastocysts (nBiX: novel blastocyst-imprinted expressed). Uniparental expression of nBiX genes disappears soon after implantation. Micro-whole-genome bisulfite sequencing (µWGBS) of individual uniparental blastocysts detects 859 DMRs. We further find that 16% of nBiX genes are associated with a DMR, whereas most are associated with parentally-biased H3K27me3, suggesting a role for Polycomb-mediated imprinting in blastocysts. nBiX genes are clustered: five clusters contained at least one published imprinted gene, and five clusters exclusively contained nBiX genes. These data suggest that early development undergoes a complex program of stage-specific imprinting involving different tiers of regulation.

2020 ◽  
Author(s):  
Laura Santini ◽  
Florian Halbritter ◽  
Fabian Titz-Teixeira ◽  
Toru Suzuki ◽  
Maki Asami ◽  
...  

ABSTRACTIn mammals, chromatin marks at imprinted genes are asymmetrically inherited to control parentally-biased gene expression. This control is thought predominantly to involve parent-specific differentially methylated regions (DMR) in genomic DNA. However, neither parent-of-origin-specific transcription nor DMRs have been comprehensively mapped. We here address this by integrating transcriptomic and epigenomic approaches in mouse preimplantation embryos (blastocysts). Transcriptome-analysis identified 71 genes expressed with previously unknown parent-of-origin-specific expression in blastocysts (nBiX: novel blastocyst-imprinted expression). Uniparental expression of nBiX genes disappeared soon after implantation. Micro-whole-genome bisulfite sequencing (μWGBS) of individual uniparental blastocysts detected 859 DMRs. Only 18% of nBiXs were associated with a DMR, whereas 60% were associated with parentally-biased H3K27me3. This suggests a major role for Polycomb-mediated imprinting in blastocysts. Five nBiX-clusters contained at least one known imprinted gene, and five novel clusters contained exclusively nBiX-genes. These data suggest a complex program of stage-specific imprinting involving different tiers of regulation.


1992 ◽  
Vol 4 (2) ◽  
pp. 205 ◽  
Author(s):  
S Pampfer ◽  
W Fan ◽  
UK Schubart ◽  
JW Pollard

The p19/SCG10 gene family encodes two structurally related cellular proteins that are implicated in signal transduction during differentiation of mammalian cells. Previous evidence suggests that both genes are expressed in a stage-specific manner but that expression of p19 is widespread, whereas that of SCG10 is restricted to developing neurons. To determine at which developmental stage these two genes are first expressed, we have probed for mRNA transcripts in preimplantation embryos and the utero-placental unit of the mouse. As determined by polymerase chain reaction (PCR) to amplify reverse-transcribed RNA, expression of both genes was detected in preimplantation embryos, although the temporal pattern was distinct. p19 mRNA appeared transiently in 2-cell embryos, was undetectable in morulae and early blastocysts and reappeared in expanded blastocysts. In contrast, embryonic expression of SCG10 mRNA commenced in morulae and was maintained through to the blastocyst stage. Interestingly, only SCG10 expression could be detected in blastocysts derived from cultures of 2-cell embryos. During the post-implantation period, SCG10 transcripts were only detected in the uterus and placenta by reverse transcriptase-PCR, whereas p19 mRNA could be detected by Northern blotting and showed stage-specific expression in both tissues. The data confirm that, at later developmental stages, expression of p19 is widespread while that of SCG10 is more restricted. The expression of both genes in preimplantation embryos suggests distinct but possibly overlapping roles for p19 and SCG10 in early mammalian development.


2019 ◽  
Vol 63 (6) ◽  
pp. 663-676 ◽  
Author(s):  
Simão Teixeira da Rocha ◽  
Anne-Valerie Gendrel

Abstract Monoallelic gene expression occurs in diploid cells when only one of the two alleles of a gene is active. There are three main classes of genes that display monoallelic expression in mammalian genomes: (1) imprinted genes that are monoallelically expressed in a parent-of-origin dependent manner; (2) X-linked genes that undergo random X-chromosome inactivation in female cells; (3) random monoallelically expressed single and clustered genes located on autosomes. The heritability of monoallelic expression patterns during cell divisions implies that epigenetic mechanisms are involved in the cellular memory of these expression states. Among these, methylation of CpG sites on DNA is one of the best described modification to explain somatic inheritance. Here, we discuss the relevance of DNA methylation for the establishment and maintenance of monoallelic expression patterns among these three groups of genes, and how this is intrinsically linked to development and cellular states.


2006 ◽  
Vol 18 (2) ◽  
pp. 63 ◽  
Author(s):  
Jacquetta M. Trasler

The acquisition of genomic DNA methylation patterns, including those important for development, begins in the germ line. In particular, imprinted genes are differentially marked in the developing male and female germ cells to ensure parent-of-origin-specific expression in the offspring. Abnormalities in imprints are associated with perturbations in growth, placental function, neurobehavioural processes and carcinogenesis. Based, for the most part, on data from the well-characterised mouse model, the present review will describe recent studies on the timing and mechanisms underlying the acquisition and maintenance of DNA methylation patterns in gametes and early embryos, as well as the consequences of altering these patterns.


2011 ◽  
Vol 11 (1) ◽  
pp. 113 ◽  
Author(s):  
Peter C McKeown ◽  
Sylvia Laouielle-Duprat ◽  
Pjotr Prins ◽  
Philip Wolff ◽  
Marc W Schmid ◽  
...  

2020 ◽  
Author(s):  
H. Marshall ◽  
A.R.C. Jones ◽  
Z.N. Lonsdale ◽  
E.B. Mallon

AbstractAllele-specific expression is when one allele of a gene shows higher levels of expression compared to the other allele, in a diploid organism. Genomic imprinting is an extreme example of this, where some genes exhibit allele-specific expression in a parent-of-origin manner. Recent work has identified potentially imprinted genes in species of Hymenoptera. However, the molecular mechanism which drives this allelic expression bias remains unknown. In mammals DNA methylation is often associated with imprinted genes. DNA methylation systems have been described in species of Hymenoptera, providing a candidate imprinting mechanism. Using previously generated RNA-Seq and whole genome bisulfite sequencing from reproductive and sterile bumblebee (Bombus terrestris) workers we have identified genome-wide allele-specific expression and allele-specific DNA methylation. The majority of genes displaying allele-specific expression are common between reproductive castes and the proportion of allele-specific expression bias generally varies between colonies. We have also identified genome-wide allele-specific DNA methylation patterns in both castes. There is no significant overlap between genes showing allele-specific expression and allele-specific methylation. These results indicate that DNA methylation does not directly drive genome-wide allele-specific expression in this species. Only a small number of the genes identified may be ‘imprinted’ and it may be these genes which are associated with allele-specific DNA methylation. Future work utilising reciprocal crosses to identify parent-of-origin DNA methylation will further clarify the role of DNA methylation in parent-of-origin allele-specific expression.


2020 ◽  
Author(s):  
Jonathan Foox ◽  
Jessica Nordlund ◽  
Claudia Lalancette ◽  
Ting Gong ◽  
Michelle Lacey ◽  
...  

AbstractDetection of DNA cytosine modifications such as 5-methylcytosine (5mC) and 5-hydroxy-methylcytosine (5hmC) is essential for understanding the epigenetic changes that guide development, cellular lineage specification, and disease. The wide variety of approaches available to interrogate these modifications has created a need for harmonized materials, methods, and rigorous benchmarking to improve genome-wide methylome sequencing applications in clinical and basic research.We present a multi-platform assessment and a global resource for epigenetics research from the FDA’s Epigenomics Quality Control (EpiQC) Group. The study design leverages seven human cell lines that are publicly available from the National Institute of Standards and Technology (NIST) and Genome in a Bottle (GIAB) consortium. These genomes were subject to a variety of genome-wide methylation interrogation approaches across six independent laboratories. Our primary focus was on cytosine modifications found in mammalian genomes (5mC, 5hmC). Each sample was processed in two or more technical replicates by three whole-genome bisulfite sequencing (WGBS) protocols (TruSeq DNA methylation, Accel-NGS, SPLAT), oxidative bisulfite sequencing (oxBS), Enzymatic Methyl-seq (EM-seq), Illumina EPIC targeted-methylation sequencing, and ATAC-seq. Each library was sequenced to high coverage on an Illumina NovaSeq 6000. The data were subject to rigorous quality assessment and subsequently compared to Illumina EPIC methylation microarrays. We provide a wide range of sequence data for commonly used genomics reference materials, as well as best practices for epigenomics research. These findings can serve as a guide for researchers to enable epigenomic analysis of cellular identity in development, health, and disease.


2021 ◽  
Vol 118 (29) ◽  
pp. e2104445118
Author(s):  
Jessica A. Rodrigues ◽  
Ping-Hung Hsieh ◽  
Deling Ruan ◽  
Toshiro Nishimura ◽  
Manoj K. Sharma ◽  
...  

Parent-of-origin–dependent gene expression in mammals and flowering plants results from differing chromatin imprints (genomic imprinting) between maternally and paternally inherited alleles. Imprinted gene expression in the endosperm of seeds is associated with localized hypomethylation of maternally but not paternally inherited DNA, with certain small RNAs also displaying parent-of-origin–specific expression. To understand the evolution of imprinting mechanisms in Oryza sativa (rice), we analyzed imprinting divergence among four cultivars that span both japonica and indica subspecies: Nipponbare, Kitaake, 93-11, and IR64. Most imprinted genes are imprinted across cultivars and enriched for functions in chromatin and transcriptional regulation, development, and signaling. However, 4 to 11% of imprinted genes display divergent imprinting. Analyses of DNA methylation and small RNAs revealed that endosperm-specific 24-nt small RNA–producing loci show weak RNA-directed DNA methylation, frequently overlap genes, and are imprinted four times more often than genes. However, imprinting divergence most often correlated with local DNA methylation epimutations (9 of 17 assessable loci), which were largely stable within subspecies. Small insertion/deletion events and transposable element insertions accompanied 4 of the 9 locally epimutated loci and associated with imprinting divergence at another 4 of the remaining 8 loci. Correlating epigenetic and genetic variation occurred at key regulatory regions—the promoter and transcription start site of maternally biased genes, and the promoter and gene body of paternally biased genes. Our results reinforce models for the role of maternal-specific DNA hypomethylation in imprinting of both maternally and paternally biased genes, and highlight the role of transposition and epimutation in rice imprinting evolution.


2021 ◽  
Author(s):  
Juliane Glaser ◽  
Julian Iranzo ◽  
Maud Borensztein ◽  
Mattia Marinucci ◽  
Angelica Gualtieri ◽  
...  

ABSTRACTGenomic imprinting refers to the mono-allelic and parent-specific expression of a subset of genes. While long recognized for their role in embryonic development, imprinted genes have recently emerged as important modulators of postnatal physiology, notably through hypothalamus-driven functions. Here, using mouse models of loss, gain and parental inversion of expression, we report that the paternally expressed Zdbf2 gene controls neonatal growth in mice, in a dose-sensitive but parent-of-origin-independent manner. We further found that Zdbf2-KO neonates failed to fully activate hypothalamic circuits that stimulate appetite, and suffered milk deprivation and diminished circulating Insulin Growth Factor 1 (IGF-1). Consequently, only half of Zdbf2-KO pups survived the first days after birth and those surviving were smaller. This study demonstrates that precise imprinted gene dosage is essential for vital physiological functions at the transition from intra- to extra-uterine life, here the adaptation to oral feeding and optimized body weight gain.


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