Parental Imprinting on Mouse Chromosome 7

1996 ◽  
Vol 45 (1-2) ◽  
pp. 41-41
Author(s):  
A.C. Ferguson-Smith

Genetic studies have shown that both a maternally and paternally inherited copy of mouse chromosome 7 are essential for normal embryogenesis. When the parental dosage is altered, such as in maternal or paternal uniparental disomy for chromosome 7 (UPD7), the resulting embryos die. This is due to the altered dosage of imprinted genes which are normally expressed only from the paternally or maternally inherited chromosome homologue. Several genes on mouse chromosome 7 are subject to parental imprinting. Mutant phenotypes seen in UPD7 embryos and chimaeras can be explained by the altered dosage of some of these genes.The mechanism(s) that causes genes to be expressed in a parental origin specific manner has not yet been determined but is believed to involve germline specific modifications to DNA and/or chromatin which are acted upon after fertilisation to affect the activity of imprinted genes. Two genes, H19 and Igf2, are located 90kb apart on the distal end of chromosome 7 and are imprinted reciprocally with the maternally inherited allele of HI9 and paternally inherited allele of Igf2 being expressed. We have used UPD7 embryos to identify epigenetic modifications that distinguish the two parental alleles in the H19 and Igf2 domain by comparing DNA and chromatin from normal and maternal UPD cobceptuses. Clear cut differences in DNA methylation and chromatin compaction were observed for the H19 gene with the paternal allele exhibiting promoter methylation and nuclease insensitivity. These were not found in sperm. In addition, no major differences were noted for the Igf2 gene, although subtle parental origin specific modifications were found. These studies suggest that the two genes may share a common regulatory mechanism which controls their reciprocal imprinting.

2004 ◽  
Vol 24 (9) ◽  
pp. 3588-3595 ◽  
Author(s):  
Kye-Yoon Park ◽  
Elizabeth A. Sellars ◽  
Alexander Grinberg ◽  
Sing-Ping Huang ◽  
Karl Pfeifer

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.


1996 ◽  
Vol 45 (1-2) ◽  
pp. 87-89
Author(s):  
R.D. Nicholls ◽  
M.T.C. Jong ◽  
C.C. Glenn ◽  
J. Gabriel ◽  
P.K. Rogan ◽  
...  

Our studies aim to identify the mechanisms and genes involved in genomic imprinting in mammalian development and human disease. Imprinting refers to an epigenetic modification of DNA that results in parent-of-origin specific expression during embryogenesis and in the adult. This imprint is reset at each generation, depending on the sex of the parental gametogenesis. Prader-Willi (PWS) and Angelman (AS) syndromes are excellent models for the study of genomic imprinting in humans, since these distinct neurobehavioural disorders are both associated with genetic abnormalities (large deletions, uniparental disomy, and imprinting mutations) of inheritance in chromosome 15q11-q13, dependent on the parental origin (reviewed in ref. 1). Some AS patients have biparental inheritance, consistent with a single imprinted gene (active on the maternal chromosome), whereas similar PWS patients are not found suggesting that at least two imprinted genes (active on the paternal allele) may be necessary for classical PWS. We have previously shown that the small ribonucleoprotein associated protein SmN gene (SNRPN), located in the PWS critical region [2], is only expressed from the paternal allele and is differentially methylated on parental alleles [3]. Therefore, SNRPN may have a role in PWS. Methylation imprints have also been found at two other loci in 15q11-q13, PW71 [4] and D15S9 [5], which map 120 kb and 1.5 Mb proximal to SNRPN, respectively. We have now characterized in detail the gene structure and expression from two imprinted loci within 15q11-q13, SNRPN and D15S9, which suggests that both loci are surprisingly complex, with important implications for the pathogenesis of PWS.


1993 ◽  
Vol 339 (1288) ◽  
pp. 165-172 ◽  

Parental genomes in mammals are programmed in the germline with heritable epigenetic modifications that exert control on the expression of specific (imprinted) genes. DNA methylation is one form of epigenetic modification which shows marked genome-wide variations in the germline and during early development. Certain transgene loci also demonstrate (reversible) germline-specific methylation imprints that are heritable in somatic tissues during development. Recently, four endogenous genes have been identified whose expression is dependent on their parental origin. The mechanism of genomic imprinting and the role of imprinted genes during development is beginning to be analysed. Three of these genes map to the mouse chromosome 7. Human chromosomes 11p13, 11p15, and 15ql 1-13 are associated with disorders exhibiting parental origin effects in their patterns of inheritance. These regions share syntenic homology with mouse chromosome 7. The relationship between parental imprints, germ line-dependent epigenetic inheritance and totipotency is also under investigation using embryonic stem cells derived from the epiblast. These cells are pluripotent or totipotent and evidence indicates the presence of at least the primary parental imprints. However, imprints inherited from the paternal germline in androgenetic cells are apparently more stable than those from the female germline in parthenogenetic cells.


2007 ◽  
Vol 28 (3) ◽  
pp. 1092-1103 ◽  
Author(s):  
Rosemary Oh ◽  
Rita Ho ◽  
Lynn Mar ◽  
Marina Gertsenstein ◽  
Jana Paderova ◽  
...  

ABSTRACT The distal end of mouse chromosome 7 (Chr 7) contains a large cluster of imprinted genes. In this region two cis-acting imprinting centers, IC1 (H19 DMR) and IC2 (KvDMR1), define proximal and distal subdomains, respectively. To assess the functional independence of IC1 in the context of Chr 7, we developed a recombinase-mediated chromosome truncation strategy in embryonic stem cells and generated a terminal deletion allele, DelTel7, with a breakpoint in between the two subdomains. We obtained germ line transmission of the truncated Chr 7 and viable paternal heterozygotes, confirming the absence of developmentally required paternally expressed genes distal of Ins2. Conversely, maternal transmission of DelTel7 causes a midgestational lethality, consistent with loss of maternally expressed genes in the IC2 subdomain. Expression and DNA methylation analyses on DelTel7 heterozygotes demonstrate the independent imprinting of IC1 in absence of the entire IC2 subdomain. The evolutionarily conserved linkage between the subdomains is therefore not required for IC1 imprinting on Chr 7. Importantly, the developmental phenotype of maternal heterozygotes is rescued fully by a paternally inherited deletion of IC2. Thus, all the imprinted genes located in the region and required for normal development are silenced by an IC2-dependent mechanism on the paternal allele.


2008 ◽  
Vol 54 (3) ◽  
pp. 491-499 ◽  
Author(s):  
Sara Bruce ◽  
Katariina Hannula-Jouppi ◽  
Cecilia M Lindgren ◽  
Marita Lipsanen-Nyman ◽  
Juha Kere

Abstract Background: Epigenetic studies, such as the measurement of DNA methylation, are important in the investigation of syndromes influenced by imprinted genes. Quick and accurate quantification of methylation at such genes can be of appreciable diagnostic aid. Methods: We first digested genomic DNA with methylation-sensitive restriction enzymes and used DNA without digestion as a control and nonmethylated λ DNA as an internal control for digestion efficiency. We then performed quantitative real-time PCR analyses with 6 unique PCR assays to investigate 4 imprinting control regions on chromosomes 7 and 11 in individuals with uniparental disomy of chromosome 7 (UPD7) and in control individuals. Results: Our validation of the method demonstrated both quantitative recovery and low methodologic imprecision. The imprinted loci on chromosome 7 behaved as expected in maternal UPD7 (100% methylation) and paternal UPD7 (<10% methylation). In controls, the mean (SD) for percent methylation at 2 previously well-studied restriction sites were 46% (6%) for both H19 and KCNQ1OT1, a result consistent with the previously observed methylation rate of approximately 50%. The methylation percentages of all investigated imprinted loci were normally distributed, implying that the mean and SD can be used as a reference for screening methylation loss or gain. Conclusion: The investigated loci are of particular importance for investigating the congenital Silver–Russell and Beckwith–Wiedemann syndromes; however, the method can also be applied to other imprinted regions. This method is easy to set up, has no PCR bias, requires small amounts of DNA, and can easily be applied to large patient populations for screening the loss or gain of methylation.


1998 ◽  
Vol 72 (3) ◽  
pp. 237-245 ◽  
Author(s):  
JUSTIN F-X. AINSCOUGH ◽  
ROSALIND M. JOHN ◽  
M. AZIM SURANI

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.


2012 ◽  
Vol 97 (11) ◽  
pp. E2188-E2193 ◽  
Author(s):  
Renuka P. Dias ◽  
Irina Bogdarina ◽  
Jean-Baptiste Cazier ◽  
Charles Buchanan ◽  
Malcolm C. Donaldson ◽  
...  

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.


2017 ◽  
Vol 55 (3) ◽  
pp. 205-213 ◽  
Author(s):  
Solveig Heide ◽  
Sandra Chantot-Bastaraud ◽  
Boris Keren ◽  
Madeleine D Harbison ◽  
Salah Azzi ◽  
...  

BackgroundThe 11p15 region contains two clusters of imprinted genes. Opposite genetic and epigenetic anomalies of this region result in two distinct growth disturbance syndromes: Beckwith-Wiedemann (BWS) and Silver-Russell syndromes (SRS). Cytogenetic rearrangements within this region represent less than 3% of SRS and BWS cases. Among these, 11p15 duplications were infrequently reported and interpretation of their pathogenic effects is complex.ObjectivesTo report cytogenetic and methylation analyses in a cohort of patients with SRS/BWS carrying 11p15 duplications and establish genotype/phenotype correlations.MethodsFrom a cohort of patients with SRS/BWS with an abnormal methylation profile (using ASMM-RTQ-PCR), we used SNP-arrays to identify and map the 11p15 duplications. We report 19 new patients with SRS (n=9) and BWS (n=10) carrying de novo or familial 11p15 duplications, which completely or partially span either both telomeric and centromeric domains or only one domain.ResultsLarge duplications involving one complete domain or both domains are associated with either SRS or BWS, depending on the parental origin of the duplication. Genotype-phenotype correlation studies of partial duplications within the telomeric domain demonstrate the prominent role of IGF2, rather than H19, in the control of growth. Furthermore, it highlights the role of CDKN1C within the centromeric domain and suggests that the expected overexpression of KCNQ1OT1 from the paternal allele (in partial paternal duplications, excluding CDKN1C) does not affect the expression of CDKN1C.ConclusionsThe phenotype associated with 11p15 duplications depends on the size, genetic content, parental inheritance and imprinting status. Identification of these rare duplications is crucial for genetic counselling.


2020 ◽  
Vol 32 (4) ◽  
pp. 297-304
Author(s):  
Dirk Prawitt ◽  
Thomas Haaf

Abstract Genomic imprinting ensures the parent-specific expression of either the maternal or the paternal allele, by different epigenetic processes (DNA methylation and histone modifications) that confer parent-specific marks (imprints) in the paternal and maternal germline, respectively. Most protein-coding imprinted genes are involved in embryonic growth, development, and behavior. They are usually organized in genomic domains that are regulated by differentially methylated regions (DMRs). Genomic imprints are erased in the primordial germ cells and then reset in a gene-specific manner according to the sex of the germline. The imprinted genes regulate and interact with other genes, consistent with the existence of an imprinted gene network. Defects of genomic imprinting result in syndromal imprinting disorders. To date a dozen congenital imprinting disorders are known. Usually, a given imprinting disorder can be caused by different types of defects, including point mutations, deletions/duplications, uniparental disomy, and epimutations. Causative trans-acting factors in imprinting disorders, including ZFP57 and the subcortical maternal complex (SCMC), have the potential to affect multiple DMRs across the genome, resulting in a multi-locus imprinting disturbance. There is evidence that mutations in components of the SCMC can confer an increased risk for imprinting disorders.


Development ◽  
2000 ◽  
Vol 127 (21) ◽  
pp. 4719-4728 ◽  
Author(s):  
P. Georgiades ◽  
M. Watkins ◽  
M.A. Surani ◽  
A.C. Ferguson-Smith

Genetic analysis has shown that the distal portion of mouse chromosome 12 is imprinted; however, the developmental roles of imprinted genes in this region are not known. We have therefore generated conceptuses with uniparental disomy for chromosome 12, in which both copies of chromosome 12 are either paternally or maternally derived (pUPD12 and mUPD12, respectively). Both types of UPD12 result in embryos that are non-viable and that exhibit distinct developmental abnormalities. Embryos with pUPD12 die late in gestation, whereas embryos with mUPD12 can survive to term but die perinatally. The mUPD12 conceptuses are invariably growth-retarded while pUPD12 conceptuses exhibit placentomegaly. Skeletal muscle maturation defects are evident in both types of UPD12. In addition, embryos with paternal UPD12 have costal cartilage defects and hypo-ossification of mesoderm-derived bones. In embryos with mUPD12, the development of the neural crest-derived middle ear ossicles is defective. Some of these anomalies are consistent with those seen with uniparental disomies of the orthologous chromosome 14 region in humans. Thus, imprinted genes on chromosome 12 are essential for viability, the regulation of prenatal growth, and the development of mesodermal and neural crest-derived lineages.


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