Key Features of Genomic Imprinting during Mammalian Spermatogenesis: Perspectives for Human assisted Reproductive Therapy: A Review
Abstract
Increasing influence of epigenetics is obvious in all medical fields including reproductive medicine. Epigenetic alterations of the genome and associated post-translational modifications of DNA binding histones equally impact gamete development and maturation, as well as embryogenesis.
Relationships between methylation and acetylation of histones and involvement of DNA methylation are important not only for chromatin remodelling but also significant to gene imprinting and thus affecting the gene expression in the embryo. Therefore, gene silencing accompanied with methylation of histones and DNA is a result of heterochromatin establishment in haploid male germ cell, the spermatid.
Complex epigenetic changes leading to the establishment of histone code and heterochromatin are regulated by a broad range of factors, such as histone deacetylases, histone methyltransferases, non-coding RNAs, and small protein modifiers ubiquitin and SUMO. These factors are candidate diagnostic targets for reproductive medicine when anomalous gene imprinting or histone modification of the gametes may disrupt embryo development or cause developmental disorders in the offspring.
Using advanced non-invasive techniques for sperm selection based on testing of epigenetic markers is a possible approach to more successful assisted reproductive therapy (ART) as well as prevention of epigenetic-origin disorders in ART babies.