P0542 An integrated approach to cattle epigenomics: genome-wide methylome and histone modification profiling

Fabiana Fabbretti , Dept. of Ecology and Biology, University of Tuscia, Viterbo, Italy
Silvia Bongiorni , Dept. for Innovation in Biological, Agro-food and Forest systems, University of Tuscia, Viterbo, Italy
Giorgio Prantera , Dept. of Ecology and Biology, University of Tuscia, Viterbo, Italy
Alessio Valentini , Dept. for Innovation in Biological, Agro-food and Forest systems, University of Tuscia, Viterbo, Italy
The genome sequence gives only a partial knowledge on the set of transmissible information from parents to offspring. A great deal of inheritance is now demonstrated to pass to the progeny as alternative epigenetic states affecting the genetic function of a sequence. The main epigenetic molecular mechanisms are represented by DNA methylation and histone posttranslational modifications, which are responsible for chromatin remodeling events that underpin epigenetic phenomena such as genomic imprinting. This study intends to profile DNA methylation and to develop a high-resolution map of histone modifications, on a genome-wide scale across the cattle genome. We selected a family trio of father-mother-progeny by crossing a bull and a cow of different breeds in order to trace back haplotypes to the origin parent. Genomic DNA from trio individuals was subjected to two kind of analysis: 1) chromatin immunopreciptation (ChIP) to isolate  active chromatin- and silent chromatin-associated DNA sequences. To this aim we focused on the following histone modifications H3K4me3/H3K36me3, and H3K9me3/H3K27me3, as characteristic of active and silent chromatin domains, respectively; 2) bisulfite sequencing to identify methylated cytosines in the genome. Resulting DNA was sequenced on the Illumina GAII platform. We established the DNA methylation and chromatin modification profile of somatic (CD4+ lynfocyte cells) and germinal cells of the parents as well as of the embryo, with the aim of identifying the default epigenome and its modifications. The outcome of this project will be the first functional landscape of the cow genome allowing a global view of  the epigenetic  inheritance in cattle.