Changes In Gene Expression During Ovine Fetal Skeletal Muscle Development And Characterization Of The Gene Interaction Networks Using Transcriptome-wide Analyses In The Second Half Of Gestation

The last half of gestation is important for tertiary myotube formation, myofiber hypertrophy, and adipocyte development in muscles, while the mechanisms behind these biological developments remain unclear. We histologically examined myofibers and determined the transcriptome profile using longissimus dorsi skeletal muscle from16fetal lambs harvested at five time points (70,85,100,120,135days of gestation).We found that the complement of myofibers form from100to120days of gestation, at which time muscle fiber size also changed significantly. The genes upregulated after100days of gestation mainly contributed to mitochondrial development, oxidative metabolism, and lipid metabolism, while the genes downregulated mainly associated with cell processes and structure. Correspondingly, enriched cis-regulatory motifs included estrogen-related receptor alpha (ESRRA) and estrogen receptor alpha in the upregulated gene group, splicing factor1(SP1) and E2F transcription factor1in the downregulated gene group. These implied that100days of ovine gestation was the hinge for myofiber and adipocyte development, and genes involved in is likely triggered by estrogen via its receptor and other related transcription factors (ESRRA, SP1).