Sperm DNA Methylation Associated with Bull Fertility

Bull fertility is crucial in the regulation of cattle reproduction. Epigenetic phenomena including DNA methylation and chromatin structure in sperm are thought to influence male fertility. However, molecular details on mechanisms by which sperm viability and early embryonic development are regulated by DNA methylation and chromatin structure are poorly defined. The objectives of this study were to determine global as well as regions bound to Histone 4 in sperm DNA from high vs. low fertility bulls, and to identify to what extent molecular underpinnings of male infertility cause epigenetic abnormalities. To accomplish our objectives, we performed global DNA profiling using Luminometric Methylation Assay (LUMA) method and are performing chromatin immunoprecipitation with Histone 4 antibodies followed by bisulfite sequencing to determine global and loci specific DNA methylation in bull sperm, respectively. Results with the global methylation profiles showed that there were no significant differences in methylation profiles of DNA from six bulls. Expected outcomes from this study are that DNA regions bound to Histone 4 in low fertility bull sperm are improperly methylated causing abnormal chromatin structure or gene expression preventing fertilization and/or early embryonic development.