scholarly journals G9a Histone Methyltransferase Contributes to Imprinting in the Mouse Placenta

2007 ◽  
Vol 28 (3) ◽  
pp. 1104-1113 ◽  
Author(s):  
Alexandre Wagschal ◽  
Heidi G. Sutherland ◽  
Kathryn Woodfine ◽  
Amandine Henckel ◽  
Karim Chebli ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Histone Methylation ◽  
Histone Methyltransferase ◽  
Chromosome 7 ◽  
Gene Repression ◽  
Imprinted Genes ◽  
Set Domain ◽  
Imprinted Gene ◽  
Mouse Placenta ◽  
Distal Chromosome

ABSTRACT Whereas DNA methylation is essential for genomic imprinting, the importance of histone methylation in the allelic expression of imprinted genes is unclear. Imprinting control regions (ICRs), however, are marked by histone H3-K9 methylation on their DNA-methylated allele. In the placenta, the paternal silencing along the Kcnq1 domain on distal chromosome 7 also correlates with the presence of H3-K9 methylation, but imprinted repression at these genes is maintained independently of DNA methylation. To explore which histone methyltransferase (HMT) could mediate the allelic H3-K9 methylation on distal chromosome 7, and at ICRs, we generated mouse conceptuses deficient for the SET domain protein G9a. We found that in the embryo and placenta, the differential DNA methylation at ICRs and imprinted genes is maintained in the absence of G9a. Accordingly, in embryos, imprinted gene expression was unchanged at the domains analyzed, in spite of a global loss of H3-K9 dimethylation (H3K9me2). In contrast, the placenta-specific imprinting of genes on distal chromosome 7 is impaired in the absence of G9a, and this correlates with reduced levels of H3K9me2 and H3K9me3. These findings provide the first evidence for the involvement of an HMT and suggest that histone methylation contributes to imprinted gene repression in the trophoblast.

scholarly journals Multiple Mechanisms Regulate Imprinting of the Mouse Distal Chromosome 7 Gene Cluster

1998 ◽  
Vol 18 (6) ◽  
pp. 3466-3474 ◽  
Author(s):  
Tamara Caspary ◽  
Michele A. Cleary ◽  
Catherine C. Baker ◽  
Xiao-Juan Guan ◽  
Shirley M. Tilghman
Keyword(s):  
Dna Methylation ◽  
Gene Cluster ◽  
Genomic Imprinting ◽  
Dna Methyltransferase ◽  
Regulatory Elements ◽  
Chromosome 7 ◽  
Imprinted Genes ◽  
Global Regulator ◽  
Loss Of Imprinting ◽  
Distal Chromosome

ABSTRACT Genomic imprinting is an epigenetic process that results in the preferential silencing of one of the two parental copies of a gene. Although the precise mechanisms by which genomic imprinting occurs are unknown, the tendency of imprinted genes to exist in chromosomal clusters suggests long-range regulation through shared regulatory elements. We characterize a 800-kb region on the distal end of mouse chromosome 7 that contains a cluster of four maternally expressed genes, H19, Mash2, Kvlqt1, andp57Kip2 , as well as two paternally expressed genes, Igf2 and Ins2, and assess the expression and imprinting of Mash2, Kvlqt1, andp57Kip2 during development in embryonic and extraembryonic tissues. Unlike Igf2 and Ins2, which depend on H19 for their imprinting,Mash2, p57Kip2 , andKvlqt1 are unaffected by a deletion of the H19gene region, suggesting that these more telomeric genes are not regulated by the mechanism that controls H19,Igf2, and Ins2. Mutations in humanp57Kip2 have been implicated in Beckwith-Wiedemann syndrome, a disease that has also been associated with loss of imprinting of IGF2. We find, however, that a deletion of the gene has no effect on imprinting within the cluster. Surprisingly, the three maternally expressed genes are regulated very differently by DNA methylation; p57Kip2 is activated, Kvlqt1 is silenced, and Mash2 is unaffected in mice lacking DNA methyltransferase. We conclude thatH19 is not a global regulator of imprinting on distal chromosome 7 and that the telomeric genes are imprinted by a separate mechanism(s).

Imprinting on distal chromosome 7 in the placenta involves repressive histone methylation independent of DNA methylation

2004 ◽  
Vol 36 (12) ◽  
pp. 1291-1295 ◽  
Author(s):  
Annabelle Lewis ◽  
Kohzoh Mitsuya ◽  
David Umlauf ◽  
Paul Smith ◽  
Wendy Dean ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Histone Methylation ◽  
Chromosome 7 ◽  
Distal Chromosome

scholarly journals The H19 Differentially Methylated Region Marks the Parental Origin of a Heterologous Locus without Gametic DNA Methylation

2004 ◽  
Vol 24 (9) ◽  
pp. 3588-3595 ◽  
Author(s):  
Kye-Yoon Park ◽  
Elizabeth A. Sellars ◽  
Alexander Grinberg ◽  
Sing-Ping Huang ◽  
Karl Pfeifer
Keyword(s):  
Dna Methylation ◽  
Mouse Chromosome ◽  
Germ Line ◽  
Transcriptional Silencing ◽  
Chromosome 7 ◽  
Differentially Methylated Region ◽  
Parental Origin ◽  
Imprinted Genes ◽  
Chromosome 5 ◽  
The Third

ABSTRACT Igf2 and H19 are coordinately regulated imprinted genes physically linked on the distal end of mouse chromosome 7. Genetic analyses demonstrate that the differentially methylated region (DMR) upstream of the H19 gene is necessary for three distinct functions: transcriptional insulation of the maternal Igf2 allele, transcriptional silencing of paternal H19 allele, and marking of the parental origin of the two chromosomes. To test the sufficiency of the DMR for the third function, we inserted DMR at two heterologous positions in the genome, downstream of H19 and at the alpha-fetoprotein locus on chromosome 5. Our results demonstrate that the DMR alone is sufficient to act as a mark of parental origin. Moreover, this activity is not dependent on germ line differences in DMR methylation. Thus, the DMR can mark its parental origin by a mechanism independent of its own DNA methylation.

Erasing genomic imprinting memory in mouse clone embryos produced from day 11.5 primordial germ cells

Development ◽  
2002 ◽  
Vol 129 (8) ◽  
pp. 1807-1817 ◽  
Author(s):  
Jiyoung Lee ◽  
Kimiko Inoue ◽  
Ryuichi Ono ◽  
Narumi Ogonuki ◽  
Takashi Kohda ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Genomic Imprinting ◽  
Nuclear Transfer ◽  
Monoallelic Expression ◽  
Parental Origin ◽  
Imprinted Genes ◽  
Specific Expression ◽  
Male And Female ◽  
Imprinted Gene ◽  
Methylation Patterns

Genomic imprinting is an epigenetic mechanism that causes functional differences between paternal and maternal genomes, and plays an essential role in mammalian development. Stage-specific changes in the DNA methylation patterns of imprinted genes suggest that their imprints are erased some time during the primordial germ cell (PGC) stage, before their gametic patterns are re-established during gametogenesis according to the sex of individuals. To define the exact timing and pattern of the erasure process, we have analyzed parental-origin-specific expression of imprinted genes and DNA methylation patterns of differentially methylated regions (DMRs) in embryos, each derived from a single day 11.5 to day 13.5 PGC by nuclear transfer. Cloned embryos produced from day 12.5 to day 13.5 PGCs showed growth retardation and early embryonic lethality around day 9.5. Imprinted genes lost their parental-origin-specific expression patterns completely and became biallelic or silenced. We confirmed that clones derived from both male and female PGCs gave the same result, demonstrating the existence of a common default state of genomic imprinting to male and female germlines. When we produced clone embryos from day 11.5 PGCs, their development was significantly improved, allowing them to survive until at least the day 11.5 embryonic stage. Interestingly, several intermediate states of genomic imprinting between somatic cell states and the default states were seen in these embryos. Loss of the monoallelic expression of imprinted genes proceeded in a step-wise manner coordinated specifically for each imprinted gene. DNA demethylation of the DMRs of the imprinted genes in exact accordance with the loss of their imprinted monoallelic expression was also observed. Analysis of DNA methylation in day 10.5 to day 12.5 PGCs demonstrated that PGC clones represented the DNA methylation status of donor PGCs well. These findings provide strong evidence that the erasure process of genomic imprinting memory proceeds in the day 10.5 to day 11.5 PGCs, with the timing precisely controlled for each imprinted gene. The nuclear transfer technique enabled us to analyze the imprinting status of each PGC and clearly demonstrated a close relationship between expression and DNA methylation patterns and the ability of imprinted genes to support development.

scholarly journals Mechanism of imprinting on mouse distal chromosome 7

1998 ◽  
Vol 72 (3) ◽  
pp. 237-245 ◽  
Author(s):  
JUSTIN F-X. AINSCOUGH ◽  
ROSALIND M. JOHN ◽  
M. AZIM SURANI
Keyword(s):  
Chromosome 7 ◽  
Parental Origin ◽  
Imprinted Genes ◽  
Critical Feature ◽  
Male Germline ◽  
Domain Type ◽  
Distal Chromosome ◽  
Type Mode ◽  
Single Allele ◽  
Female Germline

Genomic imprinting is an epigenetic mode of gene regulation that results in expression of the autosomal ‘imprinted’ genes from only a single allele, determined exclusively by parental origin. To date over 20 imprinted genes have been identified in mouse and man and these appear to lie in clusters in restricted regions on a subset of chromosomes. This may be a critical feature of imprinting suggesting a domain-type mode of regulation. Imprinted domains are replicated asynchronously, show sex-specific meiotic recombination frequencies and have CpG-rich regions that are differentially methylated, often associated with the imprinted genes themselves. Mouse distal chromosome 7 is one such domain, containing at least nine imprinted genes spanning over 1 Mb of DNA. For the maternally expressed p57Kip2 gene, passage through the female germline is essential to generate the active state, whereas passage through the male germline is needed to force the maternally expressed H19 gene into an inactive state. It is therefore possible that the mouse distal chromosome 7 imprinted domain is actually composed of two or more independently regulated subdomains.

scholarly journals Multiple Segmental Uniparental Disomy Associated with Abnormal DNA Methylation of Imprinted Loci in Silver-Russell Syndrome

2012 ◽  
Vol 97 (11) ◽  
pp. E2188-E2193 ◽  
Author(s):  
Renuka P. Dias ◽  
Irina Bogdarina ◽  
Jean-Baptiste Cazier ◽  
Charles Buchanan ◽  
Malcolm C. Donaldson ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Mrna Expression ◽  
Single Nucleotide Polymorphism Array ◽  
Uniparental Disomy ◽  
Postnatal Growth ◽  
Chromosome 7 ◽  
Imprinted Genes ◽  
Methylation Array ◽  
Maternal Uniparental Disomy ◽  
Silver Russell Syndrome

Background: Silver-Russell syndrome (SRS; online inheritance in man 180860) is a low-birth-weight syndrome characterized by postnatal growth restriction and variable dysmorphic features. Although maternal uniparental disomy (UPD) of chromosome 7 and hypomethylation of H19 have been reported in up to 50% of all cases, no unifying mechanism is apparent. Subjects and Methods: Ten patients and their parents were studied using the Illumina GoldenGate methylation array and the Illumina 370K HumHap single-nucleotide polymorphism array to identify aberrations in DNA methylation as well as genomic changes including copy number changes and uniparental disomy events. Results: We found evidence of UPD events outside chromosome 7 in all patients. In up to 30% of patients with SRS, DNA methylation changes occur in imprinted gene loci outside 11p15.5 (PEG3, PLAGL1, and GRB10), not previously consistently linked with SRS. Furthermore, hypermethylation of GRB10 was associated with increased mRNA expression. In addition, 20% of patients appear to have DNA methylation abnormalities within multiple loci. Not all the imprinted loci with methylation defects were affected directly by UPD. Conclusions: The association of widespread UPD associated with abnormal methylation and mRNA expression in imprinted genes in SRS is consistent with the concept of UPD as an initial genomic abnormality leading to unstable DNA methylation within the regulatory network of imprinted genes. Furthermore, disruption of any one of these genes may contribute to the heterogeneous clinical spectrum of SRS.

40 VARIOUS DNA METHYLATION LEVELS OF IMPRINTED GENES IN CLONED COWS FROM THE SAME DONOR CELLS

2011 ◽  
Vol 23 (1) ◽  
pp. 126
Author(s):  
M. Kaneda ◽  
S. Watanabe ◽  
S. Akagi ◽  
T. Somfai ◽  
S. Haraguchi ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Environmental Changes ◽  
Monozygotic Twins ◽  
Preimplantation Embryos ◽  
Imprinted Genes ◽  
Imprinted Gene ◽  
Donor Cells ◽  
Pcr Products ◽  
Epigenetic Patterns

Somatic cell nuclear transferred (SCNT) animals are genetically identical to the donors; however, because of epigenetic abnormalities caused by incomplete reprogramming during nuclear transfer, the efficiency of SCNT is still very low. Monozygotic twins are also genetically identical, but it is reported that their epigenetic patterns on the genome, the so-called epigenome, are different. The epigenome is easily influenced by aging, environmental changes and nutrients, therefore these effects can be predicted by comparing epigenetic differences between genetically identical animals. Here we analysed DNA methylation levels of imprinted genes, which express in a parent-of-origin specific manner, in various tissues of cloned cows derived from the same donor cells. Imprinted gene expression is controlled by DNA methylation and other epigenetic modifications and abnormal expression/methylation patterns of imprinted genes have been observed in cloned animals. These alterations also occur during in vitro development of preimplantation embryos, which suggests that imprinted genes are easily influenced by environmental changes. Therefore, we chose H19 and PEG3 imprinted genes for the analysis to determine the epigenetic differences between individual cloned cows derived from the same donor cells. From 5 cloned and 5 non-cloned cows, we isolated DNA from 8 tissues (heart, lung, liver, kidney, spleen, intestine, muscle, and spinal cord) and analysed DNA methylation levels by bisulfite sequencing method. Briefly, genomic DNA was isolated by QIAGEN DNeasy Blood & Tissue Kit and bisulfite converted by QIAGEN EpiTect Bisulfite Kits (Qiagen, Valencia, CA). After amplification, the PCR products were cloned into TA vector and at least 10 clones were sequenced in each gene/sample. In every tissue analysed, the methylation levels largely differ among tissues and individuals. On average, the paternally imprinted gene H19 was 9.4 to 47.9% methylated (average 27.6 ± 10.3%) in clones and 0.5 to 69.8% methylated (average 29.0 ± 16.8%) in non-clones. The maternally imprinted gene PEG3 was 18.8 to 82.2% methylated (average 43.5 ± 15.8%) in clones and 8.0 to 98.7% (average 48.2 ± 18.8%) in non-clones. Even though there were large variations in DNA methylation levels, the variability tends to be low in clones compared to non-clones. More specifically, the variabilities of H19 methylation levels in spleen and intestine were significantly lower in clones than those in non-clones (32.3 ± 5.4% v. 27.0 ± 19.0% and 25.1 ± 4.2% v. 45.1 ± 14.3%, respectively, F-test; P < 0.05). These results suggest for the first time that epigenetic patterns in some tissues of both clones and non-clones are influenced by genetic background; however, mostly they are varied depending on non-genetic factors.

Mouse embryos with paternal duplication of an imprinted chromosome 7 region die at midgestation and lack placental spongiotrophoblast

Development ◽  
1996 ◽  
Vol 122 (1) ◽  
pp. 265-270 ◽  
Author(s):  
K.J. McLaughlin ◽  
P. Szabo ◽  
H. Haegel ◽  
J.R. Mann
Keyword(s):  
Mouse Embryos ◽  
Chromosome 7 ◽  
Imprinted Genes ◽  
Uniparental Inheritance ◽  
Aberrant Expression ◽  
Distal Chromosome ◽  
Specific Activities ◽  
Androgenetic Embryos ◽  
Genomic Regions ◽  
Chromosome Regions

Imprinted genomic regions have been defined by the production of mice with uniparental inheritance or duplication of homologous chromosome regions. With most of the genome investigated, paternal duplication of only distal chromosomes 7 and 12 results in the lack of offspring, and prenatal lethality is presumed. Aberrant expression of imprinted genes in these two autosomal regions is therefore strongly implicated in the periimplantation lethality of androgenetic embryos. We report that mouse embryos with paternal duplication of distal chromosome 7 (PatDup.d7) die at midgestation and lack placental spongiotrophoblast. Thus, the much earlier death of androgenones must involve paternal duplication of other autosomal regions, acting independently of or synergistically with PatDup.d7. The phenotype observed is similar, if not identical to, that resulting from mutation of the imprinted distal chromosome 7 gene, Mash2, which in normal midgestation embryos exhibits spongiotrophoblast-specific maternally active/paternally inactive (m+/p-) allelic expression. Thus, the simplest explanation for the PatDup.d7 phenotype is p-/p- expression of this gene. We also confirm that PatDup.d7 embryos lack H19 RNA and posses excess Igf2 RNA as might be expected from the parental-specific activities of these genes in normal embryos.

Epigenetics Directing Therapy in Acute Lymphocytic Leukemia: Emerging Roles and New Therapies

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. SCI-36-SCI-36
Author(s):  
Kathrin M Bernt
Keyword(s):  
Dna Methylation ◽  
Clinical Trials ◽  
Histone Acetylation ◽  
Histone Methylation ◽  
Histone Methyltransferase ◽  
Demethylating Agents ◽  
Early Results ◽  
Aberrant Dna Methylation ◽  
Epigenetic Modulation ◽  
Methylation Patterns

In the last 15 years, our understanding of the contribution of epigenetic mechanisms to ALL leukemogenesis has increased exponentially. Epigenetic alterations are particularly interesting from a therapeutic standpoint, as they are potentially reversible and amenable to pharmacologic modulation. Indeed, inhibitors of DNA methylation, histone deactylation and histone methylation all have entered clinical trials, and early results for several of these agents are encouraging. Incorporating epigenetic modulation into ALL therapy may therefore hold great promise in improving tolerability and outcomes. Specifically, this session will address: - Patterns of aberrant DNA methylation and clinical trials combining "demethylating" agents with standard chemotherapy for relapsed ALL.DNA methylation patterns have been shown to correlate with outcome. Basic studies failed to conclusively link the regulation of specific genes or pathways to aberrant DNA methylation, and upfront methylation patterns poorly predict response to demethylating agents. Nevertheless, several clinical trials combining demethylating agents and chemotherapy in relapsed ALL are ongoing, with encouraging early results. These included responses of patients treated with decitabine and HyperCVAD who had previously failed to respond HyperCVAD alone. - Patterns of aberrant histone acetylation, the biology of histone acetyl transferases (HATs) and histone deacetylases (HDACS) in ALL, and clinical trials modulating histone acetylation. Histone acetylation patterns and a high frequency of deletions of the HAT CBP at relapse suggest that aberrant histone acetylation contributes to relapse and resistance. HDAC inhibitors show efficacy on ALL cells in preclinical studies, and clinical trials are ongoing. - The role of the histone acetylation "reader" protein Brd4 in ALL. In addition to "writers" (HAT) and "erasers" (HDACs), readers of histone acetylation may play a role in leukemia. Inhibition of Brd4 showed activity in several lymphoblastic leukemia models, and two Brd4 inhibitors are currently in clinical trials for relapsed/refractory hematologic malignancies including ALL. - Patterns of aberrant histone methylation, biology and therapeutic possibilities. Aberrant histone methylation is also emerging as a contributor to leukemogenesis, and may offer opportunities for therapeutic intervention. Loss of function mutations of the H3K27 histone methyltransferase EZH2 or other members of its complex (SUZ12, EED) are often found in early T-cell precursor ALL (ETP), and loss of EED or EZH2 contributes to aberrant T-cell development and leukemic transformation in mouse models. Gain of function of the H3K36 histone methyltransferase NSD2 have recently been described in pre-B ALL, raising the obvious question whether these leukemias depend on H3K36 hypermethylation, and NSD2 inhibition would have a therapeutic effect. Finally, aberrant recruitment of the histone methyltransferase DOT1L is observed in MLL-rearranged ALL, and an inhibitor of DOT1L is in clinical trials for MLL-rearranged malignancies, including ALL. Basic and translational studies support a critical role for epigenetic mechanisms in ALL leukemogenesis, drug resistance and relapse. Early results from clinical trials demonstrate that pharmacologic modulation of epigenetic modifiers can produce clinically meaningful responses. The next few years will likely see an increased number of compounds that modulate epigenetics enter clinical trials. Current assignment of patients to studies/compounds is crude, based on tumor type and status (i.e. "relapsed hematologic malignancy") or cytogenetics (i.e. MLL-rearrangement), rather than epigenetic profiling or an understanding of the biology that drives an individual patient's leukemia. As our diagnostic and therapeutic tools improve, epigenetic modulation may become an important component of ALL therapy. Disclosures Off Label Use: This presentation will include discussion of the use of decitabine, azacitidine, vorinostat, rhomidepsin and EPZ-5676 for ALL..

Altered expressions and DNA methylation of imprinted genes in chromosome 7 in brain of mouse offspring conceived from in vitro maturation

2012 ◽  
Vol 34 (3) ◽  
pp. 420-428 ◽  
Author(s):  
Ning Wang ◽  
Fang Le ◽  
Xiaozhen Liu ◽  
Qitao Zhan ◽  
Liya Wang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
In Vitro Maturation ◽  
Chromosome 7 ◽  
Imprinted Genes
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