Maternal control of genomic imprint maintenance

Genomic imprinting is a specialized transcriptional phenomenon that employs epigenetic mechanisms to facilitate parental-specific expression. Perturbations in parental epigenetic asymmetry can lead to the development of imprinting disorders, such as Beckwith-Wiedemann syndrome and Angelman syndrome. DNA methylation is one of the most widely studied epigenetic marks that characterizes imprinted regions. During gametogenesis and early embryogenesis, imprinted methylation undergoes a cycle of erasure, acquisition and maintenance. Gamete and embryo manipulations for the purpose of assisted reproduction are performed during these reprogramming events and may lead to their disruption. Recent studies point to the role of maternal-effect proteins in imprinted gene regulation. Studies are now required to increase understanding of how these factors regulate genomic imprinting as well as how assisted reproduction technologies may alter their function.