mRNA N6-methyladenosine methylation of postnatal liver development in pig

N-6-methyladenosine (m(6)A) is a ubiquitous reversible epigenetic RNA modification that plays an important role in the regulation of post-transcriptional protein coding gene expression. Liver is a vital organ and plays a major role in metabolism with numerous functions. Information concerning the dynamic patterns of mRNA m(6)A methylation during postnatal development of liver has been long overdue and elucidation of this information will benefit for further deciphering a multitude of functional outcomes of mRNA m(6)A methylation. Here, we profile transcriptome-wide m(6)A in porcine liver at three developmental stages: newborn (0 day), suckling (21 days) and adult (2 years). About 33% of transcribed genes were modified by m(6)A, with 1.33 to 1.42 m(6)A peaks per modified gene. m(6)A was distributed predominantly around stop codons. The consensus motif sequence RRm(6)ACH was observed in 78.90% of m(6)A peaks. A negative correlation (average Pearson's r = -0.45, P < 10(-16)) was found between levels of m(6)A methylation and gene expression. Functional enrichment analysis of genes consistently modified by m(6)A methylation at all three stages showed genes relevant to important functions, including regulation of growth and development, regulation of metabolic processes and protein catabolic processes. Genes with higher m(6)A methylation and lower expression levels at any particular stage were associated with the biological processes required for or unique to that stage. We suggest that differential m(6)A methylation may be important for the regulation of nutrient metabolism in porcine liver.