Transcriptome-Wide m6A Methylation Landscape of Longissimus Dorsi Muscle in Indigenous Guizhou Cattle

Guizhou cattle are important indigenous bovine genetic resources for regional beef production and germplasm conservation. This study characterized the transcriptome-wide N6-methyladenosine (m6A) enrichment landscape in longissimus dorsi muscle from three representative indigenous Guizhou cattle breeds-Guanling (GL), Wuchuan (WC), and Weining (WN)-and compared these profiles with those of Simmental (XM) cattle as a commercial reference. MeRIP-seq was used to detect group-level m6A-enriched regions and regions with differential m6A enrichment, followed by Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and database-inferred protein-protein interaction analyses. qRT-PCR was used to examine transcript abundance of selected network-prioritized candidate genes, rather than to validate m6A enrichment. MeRIP-seq detected 17,659, 19,530, 17,501, and 16,271 m6A-enriched regions in GL, WC, WN, and XM cattle, respectively. Compared with XM cattle, 2822, 5914, and 3655 regions with differential m6A enrichment were detected in GL, WC, and WN cattle, respectively. ACTB, CTNNB1, and AKT2 were prioritized for follow-up, and qRT-PCR showed breed-associated differences in their transcript abundance. These exploratory findings provide an epitranscriptomic resource and candidate targets for future MeRIP-qPCR, phenotypic, and functional studies.