Regulatory role of N6-methyladenosine in intramuscular fat deposition in chicken

Intramuscular fat (IMF) has a pivotal influence on meat quality, with its deposition being a multifaceted physiological interaction of several regulatory factors. N6-methyladenosine (m6A), the preeminent epigenetic alteration among eukaryotic RNA modifications, holds a crucial role in moderating post-transcriptional gene expression. However, there is a dearth of comprehensive understanding regarding the functional machinery of m6A modification in the context of IMF deposition in poultry. Our current study entails an analysis of the disparities in IMF within the breast and leg of 180-day-old Jingyuan chickens. We implemented methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) to delve into the distribution of m6A and its putative regulatory frameworks on IMF deposition in chickens. The findings demonstrated a markedly higher IMF content in leg relative to breast (P < 0.01). Furthermore, the expression of METTL14, WTAP, FTO, and ALKBH5 was significantly diminished in comparison to that of breast (P < 0.01). The m6A peaks in the breast and leg primarily populated 3′untranslated regions (3′UTR) and coding sequence (CDS) regions. The leg, when juxtaposed with the breast, manifested 176 differentially methylated genes (DMGs), including 151 hyper-methylated DMGs and 25 hypo-methylated DMGs. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed a pronounced enrichment of DMGs in the biosynthesis of amino acids, peroxisome, Fatty acid biosynthesis, fatty acid elongation, and cell adhesion molecules (CAMs) pathways. Key DMGs, namely ECH1, BCAT1, and CYP1B1 were implicated in the regulation of muscle lipid anabolism. Our study offers substantial insight and forms a robust foundation for further exploration of the functional mechanisms of m6A modification in modulating IMF deposition. This holds profound theoretical importance for improving and leveraging meat quality in indigenous chicken breeds.