Review: KDMIB is a histone H3K4 demethylase required to establish maternal genomic imprints

The somatic cells of diploid organisms contain two copies of the genome. With each parent contributing one copy to the offspring. Genomic imprinting is the process whereby one copy of the gene is repressed, such that only the paternally or maternally inherited copy of the gene is expressed. In mammals, imprinting is achieved via methylation of the DNA during gametogenesis in male and female germ cells. The paper by Ciccone et al (2009), demonstrates that demethylation of the histone H3 lysine 4 (H3K4), by the lysine demethylase 1B (KDM1B) is needed to establish DNA methylation imprinting during the late stages of oogenesis. Methylation of the histone H3 protien interferes with the DNA methylation of the loci targeted for imprinting. Thus demethylation of the histone H3 protein may be required to allow better access of the DNA to DNA methyltransferase activity. The paper provides evidence for the role of the KDM1B demethylase in maternal genomic imprinting for several genes examined in the study.

Emily Chan