Abstract / Summary
Background: The pronounced broodiness of Wanxi white geese is associated with rapid ovarian regression and reduced egg production and reproductive efficiency. However, the extent to which circRNAs influence this physiological transition by coordinating ceRNA interactions is not yet well understood. Methods: Here, we generated ovarian microRNA (miRNA) and circRNA expression profiles by RNA sequencing in late-laying (LLG) and nesting (NG) Wanxi white geese and measured serum reproductive hormones. Results: Compared with the late-laying stage, the nesting stage was characterised by pronounced ovarian atrophy. Serum concentrations of oestradiol (E2), progesterone (P4) and luteinising hormone (LH) were lower, whereas the prolactin (PRL) concentration was higher. Transcriptome analysis identified 156 circRNAs and 64 miRNAs that met the nominal differential expressed (DE) criteria. Enrichment analysis associated genes giving rise to DE circRNAs with membrane and junctional structures, cell adhesion, small GTPase regulation, ECM–receptor interaction, adherens junction, focal adhesion and metabolic processes. Conversely, putative targets of DE miRNAs were linked to AMPK, mTOR, TGF-β and Hippo pathways, together with oocyte meiosis. The integration of the RNA datasets and Pearson correlation analysis highlighted several putative ceRNA relationships associated with ovarian functional transition. During the late-laying period, bioinformatic predictions and expression correlations supported the predicted novel_circ_001280-miR-1-y-CPEB1 and novel_circ_005385-miR-187-x-BMP6 relationships involving genes associated with oocyte development and ovarian endocrine function. By contrast, during the nesting period, bioinformatic analyses supported a putative novel_circ_002435/novel_circ_007511-miR-135-x/z-FOXO3 relationship that may be associated with cellular quiescence, stress responses and follicular atresia. The expression profiles of these network components showed stage-associated correlations with circulating reproductive hormone concentrations. Conclusions: Together, these findings suggest an exploratory ceRNA landscape associated with ovarian functional remodelling in Wanxi white geese and identify RNA relationships that warrant further functional validation.