Whole genome DNA methylation profile of sperm cells in mammalian species
Ontology highlight
ABSTRACT:
ORGANISM(S): Rattus norvegicus Canis lupus familiaris Gorilla gorilla
PROVIDER: GSE79566 | GEO | 2017/12/14
SECONDARY ACCESSION(S): PRJNA316191
REPOSITORIES: GEO
Similar Datasets
Project description:During germ cell and preimplantation development, mammalian cells undergo nearly complete reprogramming of DNA methylation patterns. We profiled the methylomes of human and chimp sperm as a basis for comparison to methylation patterns of ES cells. While the majority of promoters escape methylation in both ES cells and sperm, the corresponding hypomethylated regions show substantial structural differences. Repeat elements are heavily methylated in both germ and somatic cells; however, retrotransposons from several subfamilies evade methylation more effectively during male germ cell development, while other subfamilies show the opposite trend. Comparing methylomes of human and chimp sperm revealed a subset of differentially methylated promoters and strikingly divergent methylation in retrotransposon subfamilies, with an evolutionary impact that is apparent in the underlying genomic sequence. Thus, the features that determine DNA methylation patterns differ between male germ cells and somatic cells, and elements of these features have diverged between humans and chimpanzees.
2011-09-01 | GSE30340 | GEO
Project description:The genomes of many vertebrates show a characteristic variation in GC content. To explain its origin and evolution mainly three mechanisms have been proposed, selection for GC content, mutation bias and GC-biased gene conversion. At present the mechanism of GC-biased gene conversion, i.e. short-scale, unidirectional exchanges between homologous chromosomes in the neighborhood of recombination-initiating double-strand breaks in favor for GC nucleotides, is the most widely accepted hypothesis. We here suggest that DNA methylation also plays an important role in the evolution of GC content in vertebrate genomes. To test this hypothesis we investigated one mammalian (human; GSE30340) and one avian (chicken) genome. We used bisulfite sequencing to generate a whole-genome methylation map of chicken sperm. Human processed data files (spermdonor1, #reads>=1) were downloaded from the NGSmethDB database (http://bioinfo2.ugr.es/NGSmethDB/database.php). Inclusion of these methylation maps into a model of GC content evolution provided significant support for the impact of DNA methylation on the local equilibrium GC content. Moreover, two different estimates of equilibrium GC content, one which neglects and one which incorporates the impact of DNA methylation and the concomitant CpG hypermutability, give estimates that differ about 15% in both genomes, arguing for a strong impact of DNA methylation on the evolution of GC content. Thus, our results put forward that previous estimates of equilibrium GC content, which neglect the hypermutability of CpG dinucleotides, need to be reevaluated. Genomic DNA from chicken mature sperm was isolated, bisulfite converted and sequenced on a Illumina HiSeq instrument
2015-01-23 | E-GEOD-56639 | biostudies-arrayexpress
Project description:DNA methylation has been found throughout animal kingdom, but it is still unclear whether this epigenetic mechanism affects the evolution of genomic elements in animals. Here, we compare the DNA methylomes of gametes and embryos from 7 representative animal species. We find that parental methylomes are propagated to the progeny without significant changes during embryogenesis in cnidarians and insects, but undergo substantial reprogramming in echinoderms, and the reprogramming become more dramatic during deuterostome evolution. Interestingly, young gene promoters in mammals tend to be reprogrammed, usually have low CpG density, don’t contain CpG Islands (CGIs) and are hypermethylated, and the hypermethylated status correlates to lower transcription. Unexpectedly, an evolutionary trend of CpG accumulation in promoters is observed only during vertebrate evolution. Most of ancient gene promoters in mammals form CGIs, which are generally unmethylated and associate with higher transcription. Thus, to gain unmethylated pattern to facilitate transcription, nature selection should be in favor of the formation of CGIs in promoters. Our data suggest that the formation of CGIs in promoters is driven by DNA methylation during mammalian evolution.
2019-11-17 | GSE73545 | GEO
Project description:Methylation is a repressive modification of DNA prevalent throughout mammalian genomes yet mostly absent at CG rich stretches referred to as CGI. Here we identify their building principles by parallel genomic targeting of sequence libraries. Iterative insertions generated over 3,000 variants of genome-derived and artificial sequences at the same genomic site. Single molecule profiling of the methylation status of this collection allowed modeling the contribution of CG content and DNA binding factors towards the unmethylated state. It made the surprising prediction that the majority of CGs within endogenous islands are susceptible to methylation changes modulated by the presence of transcription factors, which is indeed confirmed by genome-wide methylation dynamics during multiple cellular differentiations. Our model further predicts blocks of constitutively unmethylated CGs independent from TF binding, which have a median size of ~300bp but are only present in half of all islands. Their constitutively unmethylated state is a hallmark of untransformed cells but their increased methylation is a specific and predictive feature of cancer. This study quantifies the two principal mechanisms governing methylation patterns in mammalian genomes. It provides a framework to interpret methylation data across normal and cancer samples and refines the concept of CpG islands. Methylation is a repressive modification of DNA prevalent throughout mammalian genomes yet mostly absent at CG rich stretches referred to as CGI. Here we identify their building principles by parallel genomic targeting of sequence libraries. Iterative insertions generated over 3,000 variants of genome-derived and artificial sequences at the same genomic site. Single molecule profiling of the methylation status of this collection allowed modeling the contribution of CG content and DNA binding factors towards the unmethylated state. It made the surprising prediction that the majority of CGs within endogenous islands are susceptible to methylation changes modulated by the presence of transcription factors, which is indeed confirmed by genome-wide methylation dynamics during multiple cellular differentiations. Our model further predicts blocks of constitutively unmethylated CGs independent from TF binding, which have a median size of ~300bp but are only present in half of all islands. Their constitutively unmethylated state is a hallmark of untransformed cells but their increased methylation is a specific and predictive feature of cancer. This study quantifies the two principal mechanisms governing methylation patterns in mammalian genomes. It provides a framework to interpret methylation data across normal and cancer samples and refines the concept of CpG islands. Libraries of DNA sequences were constructed either by mouse genome (129S6) or E.coli genome (NC_010473.1) subrepresentation or custom synthesis. DNA fragments were inserted into the genome of mouse embryonic stem cells by recombination mediated casette exchange (RMCE) at the B-globin locus. Methylation status of the inserted DNA sequences was profiled by bisulfite sequencing using a pair of universal primers flanking the fragments.
2014-09-30 | E-GEOD-51170 | biostudies-arrayexpress
Project description:Methylation is a repressive modification of DNA prevalent throughout mammalian genomes yet mostly absent at CG rich stretches referred to as CGI. Here we identify their building principles by parallel genomic targeting of sequence libraries. Iterative insertions generated over 3,000 variants of genome-derived and artificial sequences at the same genomic site. Single molecule profiling of the methylation status of this collection allowed modeling the contribution of CG content and DNA binding factors towards the unmethylated state. It made the surprising prediction that the majority of CGs within endogenous islands are susceptible to methylation changes modulated by the presence of transcription factors, which is indeed confirmed by genome-wide methylation dynamics during multiple cellular differentiations. Our model further predicts blocks of constitutively unmethylated CGs independent from TF binding, which have a median size of ~300bp but are only present in half of all islands. Their constitutively unmethylated state is a hallmark of untransformed cells but their increased methylation is a specific and predictive feature of cancer. This study quantifies the two principal mechanisms governing methylation patterns in mammalian genomes. It provides a framework to interpret methylation data across normal and cancer samples and refines the concept of CpG islands. Methylation is a repressive modification of DNA prevalent throughout mammalian genomes yet mostly absent at CG rich stretches referred to as CGI. Here we identify their building principles by parallel genomic targeting of sequence libraries. Iterative insertions generated over 3,000 variants of genome-derived and artificial sequences at the same genomic site. Single molecule profiling of the methylation status of this collection allowed modeling the contribution of CG content and DNA binding factors towards the unmethylated state. It made the surprising prediction that the majority of CGs within endogenous islands are susceptible to methylation changes modulated by the presence of transcription factors, which is indeed confirmed by genome-wide methylation dynamics during multiple cellular differentiations. Our model further predicts blocks of constitutively unmethylated CGs independent from TF binding, which have a median size of ~300bp but are only present in half of all islands. Their constitutively unmethylated state is a hallmark of untransformed cells but their increased methylation is a specific and predictive feature of cancer. This study quantifies the two principal mechanisms governing methylation patterns in mammalian genomes. It provides a framework to interpret methylation data across normal and cancer samples and refines the concept of CpG islands.
2014-09-30 | GSE51170 | GEO
Project description:The genomes of many vertebrates show a characteristic variation in GC content. To explain its origin and evolution mainly three mechanisms have been proposed, selection for GC content, mutation bias and GC-biased gene conversion. At present the mechanism of GC-biased gene conversion, i.e. short-scale, unidirectional exchanges between homologous chromosomes in the neighborhood of recombination-initiating double-strand breaks in favor for GC nucleotides, is the most widely accepted hypothesis. We here suggest that DNA methylation also plays an important role in the evolution of GC content in vertebrate genomes. To test this hypothesis we investigated one mammalian (human; GSE30340) and one avian (chicken) genome. We used bisulfite sequencing to generate a whole-genome methylation map of chicken sperm. Human processed data files (spermdonor1, #reads>=1) were downloaded from the NGSmethDB database (http://bioinfo2.ugr.es/NGSmethDB/database.php). Inclusion of these methylation maps into a model of GC content evolution provided significant support for the impact of DNA methylation on the local equilibrium GC content. Moreover, two different estimates of equilibrium GC content, one which neglects and one which incorporates the impact of DNA methylation and the concomitant CpG hypermutability, give estimates that differ about 15% in both genomes, arguing for a strong impact of DNA methylation on the evolution of GC content. Thus, our results put forward that previous estimates of equilibrium GC content, which neglect the hypermutability of CpG dinucleotides, need to be reevaluated.
2015-01-23 | GSE56639 | GEO
Project description:Nucleosomes are the principal packaging units of chromatin and critical for gene regulation and genome stability. In mammals, a subset of nucleosomes fail to be replaced by protamines during spermatogenesis and are retained in mature spermatozoa providing opportunities for paternal epigenetic transmission. In humans, the remaining 10% localize at regulatory elements of genes. To assess evolutionary conservation and to dissect the molecular logic underlying nucleosome retention, we determined the genome wide nucleosome occupancy in mouse spermatozoa that only contain 1% residual histones. In striking contrast to mammalian somatic cells and haploid round spermatids, we observe high enrichment of nucleosomes at CpG-rich sequences throughout the genome, at conserved regulatory sequences as well as at intra- and intergenic regions and repetitive DNA. This preferred occupancy occurs mutually exclusive with DNA methylation both in mouse and human sperm. At unmethylated CpG-rich sequences, residing nucleosomes are largely composed of the H3.3 histone variant, and trimethylated at lysine 4 (H3K4me3). Both canonical H3.1/H3.2 and H3.3 variant histones are present at promoters marked by Polycomb-mediated H3K27me3, which is strongly predictive for gene repression in pre-implantation embryos. Our data indicate important roles of DNA sequence composition, DNA methylation, variant H3.3 and canonical H3.1/H3.2 histones and associated modifications in nucleosome retention versus eviction during the histone-to-protamine remodeling process in elongating spermatids and potentially in epigenetic inheritance by nucleosomes between generations. Identification of histone, histone variant and histone modification states in round spermatids and sperm
2013-06-15 | E-GEOD-42629 | biostudies-arrayexpress
Project description:While the majority of RNA polymerase II initiation events in mammalian genomes take place within CpG island (CGI) promoters, our understanding of their regulation remains limited. Here we combine single-molecule footprinting with interaction proteomics to identify BANP as a critical CGI regulator and the long sought-after TF that binds the orphan CGCG element in mouse and human. We show that BANP drives the activity of essential metabolic genes in the mouse genome in pluripotent and terminally differentiated cells. However, BANP binding is strongly repelled by DNA methylation of its motif in vitro and in vivo, which epigenetically restricts most binding to CGIs and accounts for its absence at aberrantly methylated CGIs in cancer cells. Upon binding to an unmethylated motif, BANP opens chromatin and phases nucleosomes. Our results establish Banp as a critical activator and put forth a model whereby CGI promoter activity relies on methylation-sensitive TFs capable of chromatin opening.
2021-06-16 | PXD024794 | Pride
Project description:Vertebrates have highly methylated genomes at CpG positions while most invertebrates have sparsely methylated genomes. Therefore, hypermethylation is considered a major innovation that shaped the genome and the regulatory roles of DNA methylation in vertebrates. However, here we report that the marine sponge Amphimedon queenslandica, belonging to one of the earliest branching animal lineages, has evolved a hypermethylated genome with remarkable similarities to that of a vertebrate. Despite major differences in genome size and architecture, independent acquisition of hypermethylation reveal common distribution patterns and repercussions for genome regulation between both lineages. Genome wide depletion of CpGs is counterbalanced by CpG enrichment at unmethylated promoters, mirroring CpG islands. Furthermore, a subset of CpG-bearing transcription factor motifs are enriched at Amphimedon unmethylated promoters. We find that the animal-specific transcription factor NRF has conserved methyl-sensitivity over 700 million years, indicating an ancient cross-talk between transcription factors and DNA methylation. Finally, the sponge shows vertebrate-like levels of 5-hydroxymethylcytosine, the oxidative derivative of cytosine methylation involved in active demethylation. Hydroxymethylation is concentrated in regions that are enriched for transcription factor motifs and show developmentally dynamic demethylation. Together, these findings push back the links between DNA methylation and its regulatory roles to the early steps of animal evolution. Thus, the Amphimedon methylome challenges the prior hypotheses about the origins of vertebrate genome hypermethylation and its implications for regulatory complexity.
2019-08-02 | GSE124016 | GEO
Project description:DNA methylation is an important epigenetic modification that undergoes dynamic changes in mammalian embryogenesis, during which both parental genomes are reprogrammed. Despite the many immunostaining studies that have assessed global methylation, the gene-specific DNA methylation patterns in bovine preimplantation embryos are unknown. Using reduced representation bisulfite sequencing, we determined genome-scale DNA methylation patterns of bovine sperm and individual in vivo developed oocytes and preimplantation embryos. We show that: 1) the major wave of genome-wide demethylation was completed by the 8-cell stage; 2) promoter methylation was significantly and inversely correlated with gene expression at the 8-cell and blastocyst stages; 3) sperm and oocytes have numerous differentially methylated regions (DMRs) - DMRs specific for sperm were strongly enriched in long terminal repeats (LTRs) and rapidly lost methylation in embryos, while the oocyte-specific DMRs were more frequently localized in exons and CpG islands (CGIs) and demethylated gradually across cleavage stages; 4) a unique set of DMRs were found between in vivo and in vitro matured oocytes; and 5) differential methylation between bovine gametes was confirmed in some but not all known imprinted genes. Our data provide insights into deciphering the complex epigenetic reprogramming of bovine early embryos and will serve as an important model for investigating human development and the evolutionary and regulatory roles of DNA methylation.
2018-08-01 | GSE110400 | GEO