Role of Tet1 in genomic imprinting erasure [RRBS-sperm]
Ontology highlight
ABSTRACT: Genomic imprinting is an allele-specific gene expression system important for mammalian development and function. The molecular basis of genomic imprinting is allele-specific DNA methylation 2. While it is well known that the de novo DNA methyltransferases Dnmt3a/b are responsible for the establishment of genomic imprinting, how the methylation mark is erased during primordial germ cell (PGC) reprogramming remains a mystery. Here we report that Tet1 plays a critical role in the erasure of genomic imprinting. We show that despite their identical genotype, progenies derived from mating between Tet1-KO males and wild-type females exhibit a number of variable phenotypes including placental, fetal and postnatal growth defects, and early embryonic lethality. These defects are, at least in part, caused by the dysregulation of imprinted genes, such as Peg10 and Peg3, which exhibit aberrant hypermethylation in the paternal allele of differential methylated regions (DMRs). RNA-seq reveals extensive dysregulation of imprinted genes in the next generation due to paternal functional loss of Tet1. Genome-wide DNA methylation analysis of E13.5 PGCs and sperm derived from Tet1-KO mice reveals hypermethylation of DMRs of imprinted genes in sperm, which can be traced back to PGCs. Dynamics of methylation change in Tet1-affected sites suggested that Tet1 swipes remaining methylation including imprinted genes at late reprogramming stage. We also revealed that Tet1play a role in paternal imprinting erasure in females germline. Thus, our study establishes a critical function for Tet1 in the erasure of genomic imprinting. Genome-wide DNA methylation analysis of sperm derived from control and Tet1-KO mice
Project description:Genomic imprinting is an allele-specific gene expression system important for mammalian development and function. The molecular basis of genomic imprinting is allele-specific DNA methylation 2. While it is well known that the de novo DNA methyltransferases Dnmt3a/b are responsible for the establishment of genomic imprinting, how the methylation mark is erased during primordial germ cell (PGC) reprogramming remains a mystery. Here we report that Tet1 plays a critical role in the erasure of genomic imprinting. We show that despite their identical genotype, progenies derived from mating between Tet1-KO males and wild-type females exhibit a number of variable phenotypes including placental, fetal and postnatal growth defects, and early embryonic lethality. These defects are, at least in part, caused by the dysregulation of imprinted genes, such as Peg10 and Peg3, which exhibit aberrant hypermethylation in the paternal allele of differential methylated regions (DMRs). RNA-seq reveals extensive dysregulation of imprinted genes in the next generation due to paternal functional loss of Tet1. Genome-wide DNA methylation analysis of E13.5 PGCs and sperm derived from Tet1-KO mice reveals hypermethylation of DMRs of imprinted genes in sperm, which can be traced back to PGCs. Dynamics of methylation change in Tet1-affected sites suggested that Tet1 swipes remaining methylation including imprinted genes at late reprogramming stage. We also revealed that Tet1play a role in paternal imprinting erasure in females germline. Thus, our study establishes a critical function for Tet1 in the erasure of genomic imprinting. Genome-wide DNA methylation analysis of E13.5 PGCs from control and Tet1-KO mice
Project description:Genomic imprinting is an allele-specific gene expression system important for mammalian development and function. The molecular basis of genomic imprinting is allele-specific DNA methylation 2. While it is well known that the de novo DNA methyltransferases Dnmt3a/b are responsible for the establishment of genomic imprinting, how the methylation mark is erased during primordial germ cell (PGC) reprogramming remains a mystery. Here we report that Tet1 plays a critical role in the erasure of genomic imprinting. We show that despite their identical genotype, progenies derived from mating between Tet1-KO males and wild-type females exhibit a number of variable phenotypes including placental, fetal and postnatal growth defects, and early embryonic lethality. These defects are, at least in part, caused by the dysregulation of imprinted genes, such as Peg10 and Peg3, which exhibit aberrant hypermethylation in the paternal allele of differential methylated regions (DMRs). RNA-seq reveals extensive dysregulation of imprinted genes in the next generation due to paternal functional loss of Tet1. Genome-wide DNA methylation analysis of E13.5 PGCs and sperm derived from Tet1-KO mice reveals hypermethylation of DMRs of imprinted genes in sperm, which can be traced back to PGCs. Dynamics of methylation change in Tet1-affected sites suggested that Tet1 swipes remaining methylation including imprinted genes at late reprogramming stage. We also revealed that Tet1play a role in paternal imprinting erasure in females germline. Thus, our study establishes a critical function for Tet1 in the erasure of genomic imprinting. Gene expression analysis of E9.5 embryos
Project description:Genomic imprinting is an allele-specific gene expression system important for mammalian development and function. The molecular basis of genomic imprinting is allele-specific DNA methylation 2. While it is well known that the de novo DNA methyltransferases Dnmt3a/b are responsible for the establishment of genomic imprinting, how the methylation mark is erased during primordial germ cell (PGC) reprogramming remains a mystery. Here we report that Tet1 plays a critical role in the erasure of genomic imprinting. We show that despite their identical genotype, progenies derived from mating between Tet1-KO males and wild-type females exhibit a number of variable phenotypes including placental, fetal and postnatal growth defects, and early embryonic lethality. These defects are, at least in part, caused by the dysregulation of imprinted genes, such as Peg10 and Peg3, which exhibit aberrant hypermethylation in the paternal allele of differential methylated regions (DMRs). RNA-seq reveals extensive dysregulation of imprinted genes in the next generation due to paternal functional loss of Tet1. Genome-wide DNA methylation analysis of E13.5 PGCs and sperm derived from Tet1-KO mice reveals hypermethylation of DMRs of imprinted genes in sperm, which can be traced back to PGCs. Dynamics of methylation change in Tet1-affected sites suggested that Tet1 swipes remaining methylation including imprinted genes at late reprogramming stage. We also revealed that Tet1play a role in paternal imprinting erasure in females germline. Thus, our study establishes a critical function for Tet1 in the erasure of genomic imprinting.
Project description:Genomic imprinting is an allele-specific gene expression system important for mammalian development and function. The molecular basis of genomic imprinting is allele-specific DNA methylation 2. While it is well known that the de novo DNA methyltransferases Dnmt3a/b are responsible for the establishment of genomic imprinting, how the methylation mark is erased during primordial germ cell (PGC) reprogramming remains a mystery. Here we report that Tet1 plays a critical role in the erasure of genomic imprinting. We show that despite their identical genotype, progenies derived from mating between Tet1-KO males and wild-type females exhibit a number of variable phenotypes including placental, fetal and postnatal growth defects, and early embryonic lethality. These defects are, at least in part, caused by the dysregulation of imprinted genes, such as Peg10 and Peg3, which exhibit aberrant hypermethylation in the paternal allele of differential methylated regions (DMRs). RNA-seq reveals extensive dysregulation of imprinted genes in the next generation due to paternal functional loss of Tet1. Genome-wide DNA methylation analysis of E13.5 PGCs and sperm derived from Tet1-KO mice reveals hypermethylation of DMRs of imprinted genes in sperm, which can be traced back to PGCs. Dynamics of methylation change in Tet1-affected sites suggested that Tet1 swipes remaining methylation including imprinted genes at late reprogramming stage. We also revealed that Tet1play a role in paternal imprinting erasure in females germline. Thus, our study establishes a critical function for Tet1 in the erasure of genomic imprinting.
Project description:Genomic imprinting is an allele-specific gene expression system important for mammalian development and function. The molecular basis of genomic imprinting is allele-specific DNA methylation 2. While it is well known that the de novo DNA methyltransferases Dnmt3a/b are responsible for the establishment of genomic imprinting, how the methylation mark is erased during primordial germ cell (PGC) reprogramming remains a mystery. Here we report that Tet1 plays a critical role in the erasure of genomic imprinting. We show that despite their identical genotype, progenies derived from mating between Tet1-KO males and wild-type females exhibit a number of variable phenotypes including placental, fetal and postnatal growth defects, and early embryonic lethality. These defects are, at least in part, caused by the dysregulation of imprinted genes, such as Peg10 and Peg3, which exhibit aberrant hypermethylation in the paternal allele of differential methylated regions (DMRs). RNA-seq reveals extensive dysregulation of imprinted genes in the next generation due to paternal functional loss of Tet1. Genome-wide DNA methylation analysis of E13.5 PGCs and sperm derived from Tet1-KO mice reveals hypermethylation of DMRs of imprinted genes in sperm, which can be traced back to PGCs. Dynamics of methylation change in Tet1-affected sites suggested that Tet1 swipes remaining methylation including imprinted genes at late reprogramming stage. We also revealed that Tet1play a role in paternal imprinting erasure in females germline. Thus, our study establishes a critical function for Tet1 in the erasure of genomic imprinting.
Project description:Mammalian sperm and oocytes have different epigenetic landscapes and are organized in different fashion. Following fertilization, the initially distinct parental epigenomes become largely equalized with the exception of certain loci including imprinting control regions. How parental chromatin becomes equalized and how imprinted genes escape this wave of reprogramming is largely unknown. Here we generated high-resolution maps of parental allele-specific DNase I hypersensitive sites (DHSs) in zygotes and morula embryos by using physically-isolated parental pronuclei, as well as parthenogenetic (PG) and androgenetic (AG) embryos. Allelic transcriptome analyses revealed a high correlation between allelic DHSs and allelic gene expression not only in known imprinted genes but also in dozens of genes not previously known to be imprinted. Interestingly, we found that many paternally- expressed genes harbor paternal allele-specific DHSs (Ps-DHSs) that are highly enriched for histone H3K27 tri-methylation (H3K27me3) but devoid of DNA methylation in maternal allele. Importantly, ectopic removal of the H3K27me3 turns Ps-DHSs into bi- allelic DHSs and induces maternal allele derepression in genes that include maternal DNA methylation-independent imprinted genes Gab1, Sfmbt2, Slc38a4, and Phf17 (also known as Jade1). Thus, our study not only reveals parental allele-specific chromatin accessibility of preimplantation embryos, but also identifies maternal H3K27me3 as a DNA methylation- independent mechanism for genomic imprinting.
Project description:Previous studies have suggested an erasure of DNA methylation is required to develop the stem cells in the morula embryo. An exception involves imprinted genes that escape this DNA methylation erasure. Transgenerational differential DNA methylation regions (DMRs) have been speculated to also escape this erasure. The current study was designed to assess if morula embryos escape erasure of DDT (dichloro-diphenyl-trichloroethane)-induced transgenerational sperm DMRs. Observations demonstrate that the transgenerational sperm DMR sites are not erased, so are imprinted-like DMR sites. Interestingly, we also found that the majority of low-density CpG genomic sites had a significant increase in DNA methylation in the morula embryo compared to sperm. The general erasure of DNA methylation during embryogenesis appears applicable for high-density CpG islands, but not low-density CpG deserts.
Project description:Mouse embryo fibroblasts (MEFs) closely resemble mouse embryos and are convenient sources for biochemical studies when cell number may be limiting from mouse embryos. To derive the imprinting signature of MEFs and potentially detect novel imprinted genes we characterized them using strand- and allele-specific RNA deep sequencing. We used Sequenom allelotyping in embryo and adult organs to verify parental allele-specific expression patterns. We found correct parental allele-specific transcription of 32 known ubiquitously imprinted genes in MEFs. Our analysis did not reveal any novel imprinted genes in MEFs, but detected extended parental allele-specific transcription in several known imprinted domains: maternal allele-specific transcription downstream of Grb10 and downstream of Meg3, Rtl1as and Rian in the Dlk1-Dio3 cluster, an imprinted domain implicated in development. We detected paternal allele-specific transcription downstream of Nespas, Peg3, Peg12 and Snurf/Snrpn. These imprinted transcript extensions were not unique to MEFs, but were also present in other somatic cells. Their 5’ end points did not carry opposing chromatin marks or parental allele-specific DNA methylation, suggesting that their parental allele-specific transcription is under the control of the extended genes. Based on the imprinting signature of MEFs, they provide valid models for understanding the biochemical aspects of genomic imprinting. Strand-specific and parental allele-specific RNA-seq was done in female mouse embryo fibroblasts.
Project description:Some flowering plant and vertebrate genes are expressed primarily or exclusively from either the maternal or paternal allele, a phenomenon called genomic imprinting. Flowering plant imprinted gene expression has been described primarily in endosperm, a terminal nutritive tissue consumed by the embryo during seed development or after germination. Imprinted expression in Arabidopsis thaliana endosperm is orchestrated by differences in cytosine DNA methylation between the paternal and maternal genomes, as well as by Polycomb group (PcG) proteins. Currently only eleven imprinted Arabidopsis genes are known. Here we use extensive sequencing of cDNA libraries to identify many new paternally and maternally imprinted genes in A. thaliana endosperm, including transcription factors, proteins involved in hormone signaling, and epigenetic regulators. The imprinted status of many maternally-expressed genes is not altered by mutations in the DNA-demethylating glycosylase DEMETER, the DNA methyltransferase MET1 or the core PcG protein FIE, indicating that these genes are regulated by novel mechanisms or deposited from maternal tissues. We did not find any imprinted genes in the embryo. Our results demonstrate that imprinted gene expression, particularly from the maternal genome, is an extensive, mechanistically complex phenomenon that likely affects multiple aspects of seed development. Epigenetics Examination of genomic imprinting in Arabidopsis endosperm