Imprinting along the Kcnq1 domain on mouse chromosome 7 involves repressive histone methylation and recruitment of Polycomb group complexes

@article{Umlauf2004ImprintingAT,
  title={Imprinting along the Kcnq1 domain on mouse chromosome 7 involves repressive histone methylation and recruitment of Polycomb group complexes},
  author={David Umlauf and Yuji Goto and Ru Cao and Fr{\'e}d{\'e}rique Cerqueira and Alexandre Wagschal and Yi Zhang and Robert Feil},
  journal={Nature Genetics},
  year={2004},
  volume={36},
  pages={1296-1300}
}
Imprinted genes are clustered in domains, and their allelic repression is mediated by imprinting control regions. These imprinting control regions are marked by DNA methylation, which is essential to maintain imprinting in the embryo. To explore how imprinting is regulated in placenta, we studied the Kcnq1 domain on mouse distal chromosome 7. This large domain is controlled by an intronic imprinting control region and comprises multiple genes that are imprinted in placenta, without the… 
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TLDR
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TLDR
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Maternal H3K27me3-dependent autosomal and X chromosome imprinting
TLDR
The role of oocyte-derived histone H3 lysine 27 trimethylation in establishing autosomal imprinting and imprinted XCI is reviewed and this novel maternal H3K27me3-mediated non-canonical imprinting mechanism further emphasizes the important role of parental chromatin in development and could provide the basis for improving the efficiency of embryo cloning.
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TLDR
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Imprinting control regions (ICRs) are marked by mono-allelic bivalent chromatin when transcriptionally inactive
TLDR
The data suggest that at ICRs, chromatin bivalency has a protective role by ensuring that DNA on the paternal allele remains unmethylated and protected against spurious and unscheduled gene expression, thereby contributing to protect cell identity.
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It is proposed that an evolutionarily older imprinting mechanism limited to extraembryonic tissues was based on histone modifications, and that this mechanism was subsequently made more stable for use in embryonic lineages by the recruitment of DNA methylation.
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