Analysis of reproduction-related transcriptomes on pineal-hypothalamic-pituitary-ovarian tissues during estrus and anestrus in Tan sheep

Abstract

Seasonal estrus is an important factor limiting the fertility of some animals such as sheep. Promoting estrus in the anestrus season is one of the major ways in improving the fecundity of seasonally breeding animals. The pineal-hypothalamus-pituitary-ovary (PHPO) axis plays a decisive role in regulating animal reproduction. However, the molecular mechanisms by which the PHPO axis regulates seasonal reproduction in animals are not well understood, especially in Tan sheep. To this end, we collected pineal, hypothalamus, pituitary and ovary tissues from Tan sheep during estrus and anestrus for RNA-Sequencing, and performed bioinformatics analysis on the entire regulatory axis of the pineal-hypothalamic-pituitary-ovary (PHPO). The results showed that 940, 1,638, 750, and 971 DEGs (differentially expressed genes, DEGs) were identified in pineal, hypothalamus, pituitary and ovary, respectively. GO analysis showed that DEGs from PHPO axis-related tissues were mainly enriched in “biological processes” such as transmembrane transport, peptide and amide biosynthesis and DNA synthesis. Meanwhile, KEGG enrichment analysis showed that the bile acid secretion pathway and the neuroactive ligand-receptor interaction pathway were significantly enriched. Additionally, four potential candidate genes related to seasonal reproduction (VEGFA, CDC20, ASPM, and PLCG2) were identified by gene expression profiling and protein-protein interaction (PPI) analysis. These findings will contribute to be better understanding of seasonal reproduction regulation in Tan sheep and will serve as a useful reference for molecular breeding of high fertility Tan sheep.

Comparative Transcriptome Analysis Reveals Sexually Dimorphic Gene Expression in the Gonads of Brachymystax tsinlingensis Li

“…The neuroactive ligand-receptor interaction pathway can impact the synthesis of steroid hormones in the gonads via the HPG axis and plays an important regulatory role in ovulation [38,39]. Moreover, similar significant enrichment results were found in gonadal transcriptomic studies of chicken, sheep and goose gonads [40][41][42]. VEGF has been recognized as one of the most relevant angiogenetic factors in orchestrating folliculogenesis, and VEGF inhibition prevents follicle ovulation [43][44][45].…”

Comparative Transcriptomics Identify Key Pituitary Circular RNAs That Participate in Sheep (Ovis aries) Reproduction

“…The pituitary communicates with the hypothalamus and ovary, participates in the reproductive process in the form of hormone secretion, and also receives hormone signals from the hypothalamus and ovary, forming a complex regulatory relationship [42]. In previous studies, researchers analyzed the transcriptomes of estrus and nonestrus sheep pituitary to explore the regulatory mechanism of circRNA in sheep pituitary [25].…”

Cellular mechanism of gain-of-function mutation I173M in sheep MC4R gene identified in year-round and seasonal estrus breeds through whole-genome resequencing

“…Sheep reproduction is primarily regulated by the Pineal-Hypothalamus-Pituitary-Ovary (PHPO) axis, with its secreted reproductive hormones exhibiting seasonal uctuations, in uenced by photoperiodic changes (seasonal variations) [5][6][7][8] . In sheep, light signals received by the retina trigger changes in melatonin secretion within the pineal gland, initiating a regulatory process involving melatonin receptors and in uencing the regulation of the Thyroid-Stimulating Hormone (TSH)-Dio and KISS1-GPR54 receptor (kisspeptin-GPR54) systems 3 .…”

“…In sheep, breeds such as Hu sheep, Large Tail Han sheep, and Cele black exhibit year-round reproductive behaviors [17][18][19] . In contrast, Tibetan sheep and Tan sheep develop their gonads at speci c times of the year and demonstrate seasonal reproductive behaviors 5,15 . Therefore, using both year-round and seasonal estrus sheep breeds as models can facilitate a more comprehensive investigation into the molecular mechanisms underlying seasonal reproduction in sheep.…”