Mammalian imprinted genes are clustered in chromosomal domains. Their mono-allelic, parent-of-origin-specific expression is regulated by imprinting control regions (ICRs), which are essential sequence elements marked by DNA methylation on one of the two parental alleles. These methylation « imprints » are established during gametogenesis and, after fertilization, are somatically maintained throughout development. Nonhistone proteins and histone modifications contribute to this epigenetic process. The way ICRs mediate imprinted gene expression differs between domains. At some domains, for instance, ICRs produce long noncoding RNAs that mediate chromatin silencing. Lysine methylation on histone H3 is involved in this developmental process and is particularly important for imprinting in the placenta and brain. Together, the newly discovered chromatin mechanisms provide further clues for addressing imprinting-related pathologies in humans.
Chromatin mechanisms in genomic imprinting
Kacem, S.; Feil, R.
2009-10 / vol 20 / pages 544-556
IGMM team(s) involved in this publication
Empreinte Génomique et Développement
embryonic stem-cells; control region; repressive histone methylation; noncoding rnas; direct repeat element; evolutionary conservation; mouse igf2r gene; novo DNA methylation; parental origin; x-chromosome