Polygenic co-expression changes the testis growth, hormone secretion and spermatogenesis to prompt puberty in Hu sheep.

In most male mammals, testis undergoes increased proliferation activity and the onset of spermatogenesis during pubertal development. However, their gene expression patterns and roles in sheep remain unclear. Therefore, we used Illumina Hiseq 2000 sequencing to identify differentially expressed genes (DEGs) from 0, 30, 60, 90, 120, 150 and 180 postnatal days and characterize the transcriptional level of sheep testicular development. Among them, the DEGs changed the most in 90-150 stages. a total of 2546 (1454 up and 1092 down) and 6867 (4683 up and 2184 down) DEGs were identified in D120 vs. D90 and D150 vs. D120, respectively. Functional enrichment analysis revealed that in earlier pubertal development, testis showed higher gene expression in organ morphogenesis, vasculogenesis, neurogenesis and hormone secretion, while in later pubertal development, genes with higher expression mainly concentrated in regulating spermatogenesis process. These results indicated that testis development undergoes the transition from organ growth to spermatogenesis and the genes related to hormone secretion were expressed highly earlier than spermatogenesis during pubertal process. In addition, we found several genes such as ZFP36, TNF, HSD3B1, HSD11B2 played key roles in androgen secretion and SPAG family, SYCP family, SPATA family, SPO11, CABYR, TNP1, TNP2 and CFAP43 performed functions during spermatogenesis process. Taken together, multi-genes cooperation prompt testis development in pubertal process. Our transcriptional atlas of sheep testis provides a comprehensive insight about testicular development and pubertal process.