Stage-specific transcriptional atlas of goose satellite cells uncovers sex-biased molecular dynamics associated with embryonic skeletal muscle development

Abstract

Sexual dimorphism in avian skeletal muscle is established during embryogenesis, but the stage-resolved transcriptional programs governing this process in geese remain largely unexplored. To construct a stage-specific transcriptional atlas of muscle satellite cells (SMSCs), we performed histological examination and RNA sequencing of PAX7 + SMSCs isolated from male and female Zhedong White goose embryos across four developmental stages (E13, E15, E18, and E23). Quantitative PCR was used to validate selected differentially expressed genes (DEGs). Although myofiber morphology exhibited no overt sexual divergence, immunofluorescence revealed distinct sex- and stage-dependent dynamics, with male embryos displaying a higher PAX7 + cell abundance at E18 and females at E23. Transcriptomic profiling identified 357, 261, 312, and 672 DEGs at E13, E15, E18, and E23, respectively, uncovering a progressively intensifying sexual bias. At E13, female-biased DEGs were enriched for positional identity genes (HOXC9/C11, HOXD12/13) and pro-proliferative factors (GDF7, FGF16), whereas male-biased DEGs included adhesion molecules (IGSF10/11). At E15, females upregulated genes linked to myofiber maturation (ACTA1, MYH7B) and lipid metabolism (PLIN1, ADIPOQ), while males showed enrichment in extracellular matrix remodeling (MMP7, COL17A1) and immune-related pathways. At E18, females enhanced neuroendocrine signaling (ADCYAP1, AGTR2), whereas males upregulated contractile apparatus components (RYR1, CASQ1) and testis-associated transcripts (BRDT, DHH). By E23, females exhibited signatures of metabolic and neuromuscular optimization, whereas males showed enrichment in extracellular matrix genes (COL11A2, COL9A1/2) and masculinization-associated factors (YBX2, GGN). Temporal pathway analysis demonstrated a progression from immune/chemokine processes at E13, through cytoskeletal organization at E15 and supramolecular fiber components at E18, to DNA metabolism coupled with chemokine signaling at E23. Protein-protein interaction network analysis pinpointed stage-specific hub genes: EGFR (E13), ACTA1/ADIPOQ (E15), RAC2 (E18), and GNG10 (E23). Quantitative PCR validated eight selected DEGs. Collectively, this transcriptional atlas delineates sex-biased molecular dynamics that operate within the Zhedong White goose SMSC pool in the absence of conspicuous histological differences, and provides a foundational gene resource for prioritizing mechanistic investigations into sexually dimorphic muscle development, focusing specifically on the embryonic leg muscles.