Genomic imprinting: the influence of differential methylation in the two sexes

Abstract

Genomic imprinting is an epigenetic form of gene regulation that entails differential sex-specific methylation of the alleles of a gene. Such methylation distinguishes male and female genomes and is inherited in a parent-of-origin-specific manner. Sex-specific imprints are established in the germline during gametogenesis and remain intact throughout embryonic and postnatal development. Reprogramming of methylation patterns in gametes is essential to sex-specific inheritance of imprinted genes and assures exclusive harboring of female- and male-specific imprinted patterns in maternal and paternal gametes, respectively. The consequences of genomic imprinting are manifested by its loss, which can lead to a variety of disorders, the most prominent ones being Prader-Willi and Angelman syndromes. Although a great deal of research has been carried out to examine various imprinting mechanisms, little is known about the establishment and regulation of imprinted genes. In the present paper, we describe several epigenetic mechanisms that have relevance in imprinting and that may have impact on embryonic development, fetal growth and animal cloning.

Could Tissue-Specific Genes be Silenced in Cattle Carrying the Rob(1;29) Robertsonian Translocation?

“…Sequences of the region proximal to BTA1 centromere are known to have abundant CpG islands that could suffer methylations. The heritable modification of cytosine residues within CpG dinucleotides represents an important epigenetic mark that affects gene expression in diverse species (Vrana, 2007;Biliya & Bulla, 2010). P a r t i c u l a r l y o n B T A 1 w e b e g u n t o s t u d y g e n e s r e l a t e d t o s t r u c t u r a l p r o t e i n s o f t h e extracellular matrix that could be associated to a placental mammal-specific orthologous group including genes collagen typeVI-α 1 (Col6A 1 ), collagen typeVI-α 2 (Col6A 2 ), collagen typeVIII-α 1 (Col8A 1 ) and collagen typeVIII-α 2 (Col8A 2 ) (Elsik et al, 2009).…”

Epigenetic Impacts on Neurodevelopment: Pathophysiological Mechanisms and Genetic Modes of Action

“…Imprinting refers to when a gene, though present in two copies, is only expressed by one chromosome, dependant on parent-of-origin, i.e. a preferential transcription for either the maternal or the paternal allele (32). Imprinting is currently known for a hand full of human genes (32).…”

“…a preferential transcription for either the maternal or the paternal allele (32). Imprinting is currently known for a hand full of human genes (32). The parent-oforigin-dependant expression is regulated by which parental allele is differentially methylated, thus imprinting is an effect brought about by epigenetic control.…”

Virion protein 16 induces demethylation of DNA integrated within chromatin in a novel mammalian cell model

“…Epigenetic events are reversible and contribute to chromatin structure stability, genome integrity, the modulation of tissue-specific gene expression, embryonic development, replication timing, genomic imprinting, as well as X-chromosome inactivation in females [1][2][3][4]. DNA methylation is one of the most important molecular mechanisms mediating epigenetic regulation.…”