Hot off the press: a new role for histone modifications in genomic imprinting

Imprinted genes are expressed from either the paternal or maternal allele. Reporting in Nature Communications, scientists led by Martin Leeb have now discovered 71 previously unrecognized imprinted genes in preimplantation blastocysts. The study found that imprinting created by differential histone marks plays a more prominent role in the preimplantation blastocyst than canonical DNA methylation mechanisms.

Top left, allele-specific RNA-Seq performed on pre-implantation blastocysts from reciprocal mice hybrids to identify parent-of-origin specific gene expression; top right, genome-wide methylation analysis performed on uniparental haploid blastocysts to identify DNA methylation regions that are differentially methylated between the maternal and paternal genomes. Bottom: H3K27me3-dependent imprinting has a major impact at the pre-implantation blastocyst stage, especially for the "transient" novel imprinted genes in contrast to the more prominent role for DNA methylation-dependent imprinting at later developmental stages for canonical imprinted genes. (c) Laura Santini, Maki Asami, Martin Leeb

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