Longitudinal epi-transcriptome profiling reveals the crucial role of m6A in prenatal skeletal muscle development of pigs

BackgroundN6-methyladenosine (m6A) is the most abundant RNA modification and essentially participates in the regulation of skeletal muscle development. However, the status and function of m6A methylation in prenatal myogenesis remains unclear now. ResultsIn our present study, we first demonstrate that chemical suppression of m6A and knockdown METTL14 significantly inhibit the differentiation and promote the proliferation of C2C12 myoblast cells. The mRNA expression of m6A reader protein IGF2BP1, which functions to promote the stability of target mRNA, continually decreases during the prenatal skeletal muscle development. Thereafter, profiling transcriptome-wide m6A for six developmental stage of prenatal skeletal muscle, which spanning two important waves of pig myogenesis, were performed using a refined MeRIP sequencing technology that is optimal for small-amount of RNA samples. Highly dynamic m6A methylomes across different development stages were then revealed, with majority of the affected genes enriched in pathways of skeletal muscle development. In association with the transcriptome-wide alterations, transcriptional regulatory factors (MyoD) and differentiated markers (MyHC, MYH1) of muscle development are simultaneously regulated with m6A and IGF2BP1. Knockdown of IGF2BP1 also suppresses myotube formation and promotes cell proliferation. ConclusionsThe present study clarifies the dynamics of RNA m6A methylation in the regulation of prenatal skeletal muscle development, providing a data baseline for future developmental as well as biomedical studies of m6A functions in muscle development and disease.