Stage-specific transcriptional atlas of goose satellite cells uncovers molecular dynamics driving embryonic skeletal muscle development

Muscle development in goose embryos is a complex and highly coordinated process involving dynamic morphological and transcriptional changes. Skeletal muscle satellite cells (SMSCs) play essential roles in postnatal muscle growth, regeneration, and meat quality, yet the molecular mechanisms regulating SMSC behavior during embryonic development in geese remain incompletely characterized. In this study, we integrated histology, immunofluorescence, and transcriptomics to investigate leg muscle development and SMSC dynamics in female Zhedong White (ZW) geese at embryonic days 15, 18, and 23 (E15F, E18F, and E23F). Histological examination revealed progressive myofiber hypertrophy and alignment from E15F to E23F. Concurrently, the proportion of Pax7⁺ SMSCs progressively decreased, indicating the establishment of a quiescent satellite cell pool. RNA sequencing of SMSCs identified numerous differentially expressed genes across developmental stages. Transcriptomic profiling indicated a clear developmental transition: early stages (E15F) were enriched in genes related to structural and contractile proteins (e.g., MYL1, ACTC1, TNNT2), while later stages (E23F) were associated with upregulation of genes involved in lipid metabolism (e.g., PPARG, PLIN2, ACSL1), extracellular matrix remodeling (e.g., MMP2, SPP1), and signal transduction (e.g., FGF10, IGFBP5). Functional enrichment analysis further supported a shift from active myogenesis toward metabolic maturation and tissue reorganization. Protein-protein interaction network analysis identified a core regulatory module involving MEF2C, MEF2D, MYOD1, and MSTN. Key gene expression trends were confirmed by quantitative PCR. Together, these findings provide a comprehensive transcriptomic resource that delineates the stage-specific molecular programs guiding SMSC differentiation and functional maturation during embryonic myogenesis in geese.