Ribo-Seq Analysis-Based Elucidation of the Dynamic Translation Landscape of Yak Ovarian Tissues in Different Reproductive Stages.

Translation, plays a critical regulatory role in follicular development, ovulation, and corpus luteum formation and degeneration in the ovaries. To better understand the molecular mechanisms of reproductive regulation at the translation level in yaks, the present study analyzed gene expression changes in the ovarian tissues of yaks in different reproductive stages by using ribosome profiling and integrating RNA sequencing data. The small open reading frames (sORFs) of the ovarian tissue were characterized, and the effect of the translation efficiency of the targeted genes on their sequence features was determined. The results showed that over 80% of genes in the two groups exhibited inconsistent changes in their expression at the transcription and translation levels; this finding indicated that the changes in gene expression at both levels were not merely synergistic. The pathway enrichment analysis revealed that these differentially expressed genes were enriched in various pathways, including PI3K-Akt, MAPK, calcium signaling, and ovarian steroidogenesis. Further investigations showed that some genes related to ovarian function displayed inconsistent changes in their expression at both transcription and translation levels and exhibited dynamic changes in translation activity, including PALB2, BMP7, PIK3R2, and WNT2B. Additionally, we identified 66 predicted translatable sORFs and assessed the impact of upstream ORFs on the translation efficiency of downstream major ORFs. The present study systematically revealed the characteristics of gene expression at the translational level in yak ovarian tissues in different reproductive stages for the first time and provided a new perspective for in-depth understanding of the physiological mechanisms of yak reproduction.