Expression Patterns and Correlation Analyses of Myogenesis‐Related Genes in Sheep Fetal Semitendinosus and Longissimus Dorsi at Different Developmental Stages

This study explored the expression patterns and interrelationships of myogenesis‐related genes in the Semitendinosus and Longissimus dorsi of sheep foetuses at different developmental stages. Haematoxylin and eosin (H&E) staining was used to observe the microstructure of both tissues. The expression and localization of MyoD, MyoG, Myomaker, and Glucocorticoid Receptor (GR) proteins were detected by immunohistochemistry. Quantitative real‐time PCR and Western blotting were respectively used to detect the mRNA and protein expression of myogenesis‐related genes (MyoD, MyoG, Myf5, Myf6, Pax3, Pax7, Myomaker, Myostatin, and GR) at different developmental stages. The correlations among myogenesis‐related genes were analysed by the Pearson correlation coefficient. Finally, the regulatory elements and transcription factor binding sites in the 5′ regulatory region of sheep myogenesis‐related genes were predicted by bioinformatics analysis. Our results showed that the number and cross‐sectional area of muscle fibres in Semitendinosus were lower than those in Longissimus dorsi. The expression patterns and correlations of myogenesis‐related genes at the protein and/or mRNA levels were not entirely consistent between the two muscle groups, indicating the complexity of spatiotemporal regulation. The regulatory element analyses suggested that the potential self‐, mutual, and cooperative transcriptional regulation relationships, either direct or indirect, existed among the myogenesis‐related genes. The study provides a foundation for further exploring the gene regulatory mechanisms and molecular breeding strategies in sheep.