Epigenetic Factors and Chromosome Organization

Abstract

The term epigenetics was introduced by C. H. Waddington in 1956 to describe all the interactions between genes and their environment that lead to phenotypic expression. Today it is used to define heritable modifications in gene expression that are not based on changes in nucleotide sequence. In mammalian chromosomes, the commonly reported epigenetic markers are cytosine methylation, histone methylation, histone acetylation, histone methylation and noncoding ribonucleic acid and chromosome association.

Keywords: epigenetics; methylation; acetylation; chromosome; ICF syndrome

Figure 1.

(a) Chromosomes from an ICF patient after in situ hybridization. Probes specific for chromosome 1, classical satellite 2 (green spots) and α‐satellite (red spots). Chromosomes are associated and display a strong decondensation of regions corresponding to classical satellite 2. (b) Chromosomes 1 and 16 methylation patterns after immunofluorescence with 5‐methylcytosine antibody. On the left, normal chromosomes showing an R‐banding‐like pattern and a strong methylation of constitutive heterochromatin. On the right, chromosomes from an ICF patient with the typical undermethylation of classical satellite 2 (arrows).

Figure 2.

Methylation patterns after immunofluorescence with 5‐methylcytosine antibody in normal mouse embryos. (a) Differential methylation of parental chromosome arms observed in zygote. The large arrow indicates methylated chromosomes of maternal origin and the thin arrow indicates the undermethylated chromosomes of paternal origin. (b) Chromosomes from normal mouse embryos during preimplantation development. The asymmetrically methylated chromosomes (arrows) indicate a passive demethylation mechanism.

close

References

Bird AP and Wolffe AP (1999) Methylation‐induced repression‐belts, braces, and chromatin. Cell 99: 451–454.

Boggs BA, Cheung P, Heard E, et al. (2002) Differentially methylated forms of histone H3 show unique association patterns with inactive human X chromosomes. Nature Genetics 30: 73–76.

Heard E, Rougeulle C, Arnaud D, et al. (2001) Methylation of histone H3 at Lys9 is an early mark on the X chromosome during X inactivation. Cell 107: 727–738.

Jones DO, Cowell IG and Singh PB (2000) Mammalian chromodomain proteins: their role in genome organisation and expression. BioEssays 22: 124–137.

Kelley RL and Kuroda MI (2000) Noncoding RNA genes in dosage compensation and imprinting. Cell 103: 9–12.

Laird PW and Jaenisch R (1994) DNA methylation and cancer. Human Molecular Genetics 3: 1487–1495.

Lewin B (1998) The mystique of epigenetics. Cell 93: 301–303.

Miniou P, Jeanpierre M, Blanquet V, et al. (1994) Abnormal methylation pattern in constitutive and facultative (X inactive chromosome) heterochromatin of ICF patients. Human Molecular Genetics 3: 2093–2102.

Peters AH, Mermoud JE, O'Carroll D, et al. (2002) Histone H3 lysine 9 methylation is an epigenetic imprint of facultative heterochromatin. Nature Genetics 30: 77–80.

Peters AH, O'Carroll D, Scherthan H, et al. (2001) Loss of the Suv39h histone methyltransferases impairs mammalian heterochromatin and genome stability. Cell 107: 323–337.

Plasterk RH and Ketting RF (2000) The silence of the genes. Current Opinion in Genetics and Development 10: 562–567.

Rougier N, Bourc'his D, Molina Gomes D, et al. (1998) Chromosome methylation patterns during mammalian preimplantation development. Genes and Development 12: 2108–2113.

Turner BM (2000) Histone acetylation and an epigenetic code. BioEssays 22, 836–845.

Xu G‐L, Bestor TH, Bourc'his D, et al. (1999) Chromosome instability and immunodeficiency syndrome caused by mutations in a DNA methyltransferase gene. Nature 402: 187–191.

Further Reading

Ehrlich M (2000) DNA hypomethylation and cancer. In: Erlich M (ed.) DNA Alterations in Cancer, pp. 273–291. Natick: Eaton Publishing.

Hsieh CL (2000) Dynamics of DNA methylation pattern. Current Opinion in Genetics and Development 11: 681–692.

Jeppesen P and Turner BM (1993) The inactive X chromosome in female mammals is distinguished by a lack of histone H4 acetylation, a cytogenetic marker for gene expression. Cell 74: 281–289.

Keohane AM, O'Neill LP, Belyaev ND, Lavender JS and Turner BM (1996) X‐inactivation and histone H4 acetylation in embryonic stem cells. Developmental Biology 180: 618–630.

Knoepfler PS and Eisenman RN (1999) Sin meets NuRD and other tails of repression. Cell 99: 447–450.

Lyko F and Paro R (1999) Chromosomal elements conferring epigenetic inheritance. BioEssays 21: 824–832.

Prusiner SB, Scott MR, deArmond SJ and Cohen FE (1998) Prion protein biology. Cell 93: 337–348.

Wolffe AP and Matzke MA (1999) Epigenetics: regulation through repression. Science 286: 481–486.

Yoder JA, Walsh CP and Bestor TH (1997) Cytosine methylation and the ecology of intragenomic parasites. Trends in Genetics 13: 335–340.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Bourc'his, Déborah, and Viegas‐Péquignot, Evani(Jan 2006) Epigenetic Factors and Chromosome Organization. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0005788]