Profiling Conservation of DNA Methylation in Cattle

The 5’AMP-activated protein kinase (AMPK) gene family comprises an evolutionary conserved serine/threonine heterotrimeric protein kinase. The primary function of this kinase is regulation of cellular energy and metabolism. The activation of this gene family primarily occurs when there is a depletion of cellular ATP due to environmental and nutritional stressors, which is associated with a rise of AMP levels. Subsequently, the genes initiate energy-conserving measures within the cell to protect it from the decrease in ATP levels. The regulation of these genes has been linked to the epigenetic mechanism of methylation. Methylation is an epigenetic modification of DNA that regulates gene transcription. DNA methylation primarily involves the addition of a methyl group to the 5th carbon of cytosines that are found in CpG dinucleotides. The location of 5-methylcytosine relative to genic regions can either facilitate or prevent transcriptional machinery from binding to its target site and subsequently influence phenotypic variation. We have investigated the presence of DNA methylation in the bovine AMPK gene family. Using Combined Bisulfite Restriction Analysis and bisulfite Sanger sequencing we have shown that methylation sites are conserved in Angus and Charolais breeds of cattle in AMPK genes. Upon further analysis with bisulfite pyrosequencing we are able to report conservation of DNA methylation levels and patterns in bovine AMPK genes; PRKAA1 and PRKAB1 at28 different methylation sites in multiple breeds of cattle as well as Bison. We propose that the conserved methylation levels and patterns across cattle and Bison highlight the need of maintaining function of this protein kinase. This may represent a context in which both genetics and epigenetics come together to preserve function of a protein, vital to biological functions.