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Non-random, individual-specific methylation profiles are present at the sixth CTCF binding site in the human H19/IGF2 imprinting control region.

Tost J, Jammes H, Dupont JM, Buffat C, Robert B, Mignot TM, Mondon F, Carbonne B, Siméoni U, Grangé G, Kerjean A, Ferré F, Gut IG, Vaiman D - Nucleic Acids Res. (2006)

Bottom Line: Expression of imprinted genes is classically associated with differential methylation of specific CpG-rich DNA regions (DMRs).This epigenetic polymorphism was confined to the sixth CTCF binding site while a unique median-methylated profile was found at the third CTCF binding site as well as in the H19 promoter.The existence of three individual-specific epigenotypes in the H19 DMR in a non-pathological situation means it is important to reconsider the diagnostic value and functional importance of the sixth CTCF binding site.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire d'Epigénétique, Centre National de Génotypage, 2 rue Gaston Crémieux, 91000 Evry, France. tost@cng.fr

ABSTRACT
Expression of imprinted genes is classically associated with differential methylation of specific CpG-rich DNA regions (DMRs). The H19/IGF2 locus is considered a paradigm for epigenetic regulation. In mice, as in humans, the essential H19 DMR--target of the CTCF insulator--is located between the two genes. Here, we performed a pyrosequencing-based quantitative analysis of its CpG methylation in normal human tissues. The quantitative analysis of the methylation level in the H19 DMR revealed three unexpected discrete, individual-specific methylation states. This epigenetic polymorphism was confined to the sixth CTCF binding site while a unique median-methylated profile was found at the third CTCF binding site as well as in the H19 promoter. Monoallelic expression of H19 and IGF2 was maintained independently of the methylation status at the sixth CTCF binding site and the IGF2 DMR2 displayed a median-methylated profile in all individuals and tissues analyzed. Interestingly, the methylation profile was genetically transmitted. Transgenerational inheritance of the H19 methylation profile was compatible with a simple model involving one gene with three alleles. The existence of three individual-specific epigenotypes in the H19 DMR in a non-pathological situation means it is important to reconsider the diagnostic value and functional importance of the sixth CTCF binding site.

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Related in: MedlinePlus

Cloning and Sanger sequencing of PCR products from three placental samples corresponding to the three different profiles. SNP rs2071094 was used to determine the parent-of-origin of the methylated alleles.
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fig2: Cloning and Sanger sequencing of PCR products from three placental samples corresponding to the three different profiles. SNP rs2071094 was used to determine the parent-of-origin of the methylated alleles.

Mentions: The parental origin of the methylated strands was addressed by cloning and Sanger sequencing of PCR products from three placental samples corresponding to each one of the three different methylation profiles and heterozygous for the single nucleotide polymorphism rs2071094 (Figure 2). The hyper-methylated profile corresponds mainly to methylated DNA molecules from both the maternal and paternal origin. Similarly, the hypo-methylated profile corresponded mainly to unmethylated molecules from both parental alleles. Consistent with the classical model, the median-methylated profile corresponded to the presence of methylated molecules of paternal origin.


Non-random, individual-specific methylation profiles are present at the sixth CTCF binding site in the human H19/IGF2 imprinting control region.

Tost J, Jammes H, Dupont JM, Buffat C, Robert B, Mignot TM, Mondon F, Carbonne B, Siméoni U, Grangé G, Kerjean A, Ferré F, Gut IG, Vaiman D - Nucleic Acids Res. (2006)

Cloning and Sanger sequencing of PCR products from three placental samples corresponding to the three different profiles. SNP rs2071094 was used to determine the parent-of-origin of the methylated alleles.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1636469&req=5

fig2: Cloning and Sanger sequencing of PCR products from three placental samples corresponding to the three different profiles. SNP rs2071094 was used to determine the parent-of-origin of the methylated alleles.
Mentions: The parental origin of the methylated strands was addressed by cloning and Sanger sequencing of PCR products from three placental samples corresponding to each one of the three different methylation profiles and heterozygous for the single nucleotide polymorphism rs2071094 (Figure 2). The hyper-methylated profile corresponds mainly to methylated DNA molecules from both the maternal and paternal origin. Similarly, the hypo-methylated profile corresponded mainly to unmethylated molecules from both parental alleles. Consistent with the classical model, the median-methylated profile corresponded to the presence of methylated molecules of paternal origin.

Bottom Line: Expression of imprinted genes is classically associated with differential methylation of specific CpG-rich DNA regions (DMRs).This epigenetic polymorphism was confined to the sixth CTCF binding site while a unique median-methylated profile was found at the third CTCF binding site as well as in the H19 promoter.The existence of three individual-specific epigenotypes in the H19 DMR in a non-pathological situation means it is important to reconsider the diagnostic value and functional importance of the sixth CTCF binding site.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire d'Epigénétique, Centre National de Génotypage, 2 rue Gaston Crémieux, 91000 Evry, France. tost@cng.fr

ABSTRACT
Expression of imprinted genes is classically associated with differential methylation of specific CpG-rich DNA regions (DMRs). The H19/IGF2 locus is considered a paradigm for epigenetic regulation. In mice, as in humans, the essential H19 DMR--target of the CTCF insulator--is located between the two genes. Here, we performed a pyrosequencing-based quantitative analysis of its CpG methylation in normal human tissues. The quantitative analysis of the methylation level in the H19 DMR revealed three unexpected discrete, individual-specific methylation states. This epigenetic polymorphism was confined to the sixth CTCF binding site while a unique median-methylated profile was found at the third CTCF binding site as well as in the H19 promoter. Monoallelic expression of H19 and IGF2 was maintained independently of the methylation status at the sixth CTCF binding site and the IGF2 DMR2 displayed a median-methylated profile in all individuals and tissues analyzed. Interestingly, the methylation profile was genetically transmitted. Transgenerational inheritance of the H19 methylation profile was compatible with a simple model involving one gene with three alleles. The existence of three individual-specific epigenotypes in the H19 DMR in a non-pathological situation means it is important to reconsider the diagnostic value and functional importance of the sixth CTCF binding site.

Show MeSH
Related in: MedlinePlus