A novel transcript of MEF2D promotes myoblast differentiation and its variations associated with growth traits in chicken

Background: Development of skeletal muscle is closely related to broiler production traits. The myocyte-specific enhancer binding factor (MEF) 2D gene (MEF2D) and its variant transcripts play important parts in myogenesis. Methods: To identify the transcript variants of chicken MEF2D gene and their function, this study cloned chicken MEF2D gene and identified its transcript variants from different tissue samples. The expression levels of different transcripts of MEF2D gene in different tissues and different periods were measured, and their effects on myoblast proliferation and differentiation were investigated. Variations in MEF2D were identified and association analysis with chicken production traits carried out. Results: Four novel transcript variants of MEF2D were obtained, all of which contained highly conserved sequences, including MADS-Box and MEF2-Domain functional regions. Transcript MEF2D-V4 was expressed specifically in muscle, and its expression was increased during embryonic muscle development. The MEF2D-V4 could promote differentiation of chicken myoblasts and its expression was regulated by RBFOX2. The single nucleotide polymorphism g.36186C > T generated a TAG stop codon, caused MEF2D-V4 to terminate translation early, and was associated with several growth traits, especially on early body weight. Conclusion: We cloned the muscle-specific transcript of MEF2D and preliminarily revealed its role in embryonic muscle development.