Role for DNA methylation in genomic imprinting

@article{Li1993RoleFD,
  title={Role for DNA methylation in genomic imprinting},
  author={En Li and Caroline Beard and Rudolf Jaenisch},
  journal={Nature},
  year={1993},
  volume={366},
  pages={362-365}
}

Bovine DNA Methylation Imprints Are Established in an Oocyte Size-Specific Manner, Which Are Coordinated with the Expression of the DNMT3 Family Proteins1

TLDR
It is demonstrated for the first time that an increase in bovine imprinted gene DMR methylation occurs during oocyte growth, as is observed in mouse.

DNA methylation in genomic imprinting.

  • B. Tycko
  • Biology, Chemistry
    Mutation research
  • 1997

Exploring The Role Of Tet1 In Genomic Imprinting

TLDR
A discrete set of genomic regions that require TET1 for germline reprogramming are defined and mechanisms for stochastic imprinting defects are discussed, showing that Tet1 deficiency is associated with hypermethylation of a subset of ICRs in germ cells.

Paternal imprints can be established on the maternal Igf2-H19 locus without altering replication timing of DNA.

TLDR
Results show clearly that replication asynchrony of this region is neither the determinant factor for, nor a consequence of, epigenetic modifications that are critical for genomic imprinting, and may thus be regulated differently from methylation imprints and have a separate function.

Evolution of imprinting mechanisms: the battle of the sexes begins in the zygote

TLDR
It is shown that, for most genes from either category, the methylation imprint is derived from the oocyte, and an explanation is provided for this intriguing asymmetry.

Methylation dynamics of imprinted genes in mouse germ cells.

TLDR
It is demonstrated that maternal methylation imprints on at least one imprinted gene, Snrpn, are established during the postnatal growth phase of oogenesis, which raises the possibility that assisted reproductive technologies that involve in vitro maturation of oocytes may result in developmental abnormalities due to incomplete methylated imprints in immature oocytes.

Imprinting and epigenetic changes in the early embryo

TLDR
Recent findings on factors influencing DNA methylation establishment, maintenance, and erasure that have further elucidated the mechanisms of imprinting are summarized, while highlighting topics that require further investigation.

Imprinting in the Germ Line

TLDR
Increasing evidence indicates that the inherited and stable differential allelic methylation regulates monoallelic expression by influencing the activity of gene regulatory elements—for one allele the element is switched off by methylation, while for the other theelement is left potentially active by the lack of methylation.
...

References

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Genomic imprinting determines methylation of parental alleles in transgenic mice

TLDR
The methylation patterns of transgenic alleles were compared after transmission from mother or father in seven mouse strains carrying autosomal insertions of the same transgenic marker and showed a clear difference in DNA methylation specific for its parental origin, with the paternally inherited copy being relatively undermethylated.

Epigenetic mechanisms underlying the imprinting of the mouse H19 gene.

TLDR
The result suggests that the sequences necessary for the imprinting of H19 have been identified, and the allele-specific methylation domain, coupled to the two H19 enhancers, contains all the information necessary for its imprinting.

Parental-origin-specific epigenetic modification of the mouse H19 gene

TLDR
It is shown that specific sites in the CpG island promoter and 5′ portion of the gene are methylated only on the paternal allele, and active maternal alleles in chromatin of MatDi7 embryos are more sensitive and accessible to nucleases, therefore hypermethylation and chromatin compaction in the region of the H19 promoter is associated with repression of the paternally inherited copy of the genes.

The ontogeny of allele‐specific methylation associated with imprinted genes in the mouse.

TLDR
It is suggested that only a few DNA modifications at selective positions in imprinted genes may be candidates for playing a role in the maintenance of parental identity during development.

Parental imprinting: potentially active chromatin of the repressed maternal allele of the mouse insulin-like growth factor II (Igf2) gene.

TLDR
It is shown that the chromatin of the 5' region of the repressed Igf2 allele is potentially active for transcription rather than heterochromatic, and parental methylation differences in a region several kilobases upstream of the first exon are observed.

Inherited type of allelic methylation variations in a mouse chromosome region where an integrated transgene shows methylation imprinting.

TLDR
It is shown that only part of the transgene is affected by methylation imprinting and the methylation pattern is established before early prophase I during spermatogenesis, and it is demonstrated that transgenes do not necessarily reflect themethylation status of either the surrounding or corresponding chromosome region.

Degree of methylation of transgenes is dependent on gamete of origin

TLDR
Data is presented indicating that the methylation patterns of exogenous DNA sequences in transgenic mice can be changed by switching their gamete of origin in successive generations, and suggesting that DNA methylation can also satisfy the fourth criterion for an imprinting mechanism.

Maternal inhibition of hepatitis B surface antigen gene expression in transgenic mice correlates with de novo methylation

TLDR
This work describes a transgenic mouse strain in which the expression of the hepatitis B surface antigen gene is irreversibly repressed following its passage through the female germ line, accompanied by the methylation of all the HpaII and HhaI sites within the foreign gene.