Conserved features of imprinted differentially methylated domains
Genomic imprinting is a conserved epigenetic phenomenon in eutherian mammals, with regards both to the genes that are imprinted and the mechanism underlying the expression of just one of the parental alleles. Epigenetic modifications of alleles of imprinted genes are established during oogenesis and...
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Published in | Gene Vol. 399; no. 1; pp. 33 - 45 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Netherlands
Elsevier B.V
01.09.2007
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Subjects | |
Online Access | Get full text |
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Summary: | Genomic imprinting is a conserved epigenetic phenomenon in eutherian mammals, with regards both to the genes that are imprinted and the mechanism underlying the expression of just one of the parental alleles. Epigenetic modifications of alleles of imprinted genes are established during oogenesis and spermatogenesis, and these modifications are then inherited. Differentially methylated domains (DMDs) of imprinted genes are the genomic sites of these inherited epigenetic imprints. We previously showed that CpG-rich imperfect tandem direct repeats within three different mouse DMDs (
Snurf/Snrpn, Kcnq1 and
Igf2r), each with a unique sequence, play a central role in maintaining the differential methylation. This finding implicates repeat-related DNA structure, not sequence, in the imprinting mechanism. To better define the important features of this signal, we compared sequences of these three DMD tandem repeats among mammalian species. All DMD repeats contain short indirect repeats, many of which are organized into larger unit repeats. Even though the larger repeat units undergo deletion and addition during evolution (most likely through unequal crossovers during meiosis), the size of DMD tandem repeated regions has remained remarkably stable during mammalian evolution. Moreover, all three DMD tandem repeats have a high-CpG content, an ordered arrangement of CpG dinucleotides, and similar predicted secondary structures. These observations suggest that a structural feature or features of these DMD tandem repeats is the conserved DMD imprinting signal. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Present address: Department of Genetic Medicine and Development, Geneva University Medical School, 1, Michel-Servet, 1211 Geneva 4, Switzerland |
ISSN: | 0378-1119 1879-0038 |
DOI: | 10.1016/j.gene.2007.04.028 |