Thyroid Transcriptomics Revealed the Reproductive Regulation of miRNA in the Follicular and Luteal Phases in Small-Tail Han Sheep with Different FecB Genotypes

An Insight into Differentially Expressed Genes and MicroRNAs in the Pituitary Glands of the Two Estrous Phases of Sheep with Different FecB Genotypes

As an important class of non-coding RNAs, miRNAs participate in a variety of biological processes, including cell proliferation, differentiation, apoptosis, and hormone secretion. However, little is known about the role of pituitary miRNAs in follicular development in FecB mutant (Fecundity Booroola) sheep. Given the critical role of the pituitary gland in follicular development, this study employed miRNA-seq technology to analyze pituitary transcriptome expression patterns during the follicular phase (F) and the luteal phase (L) of FecB mutant homozygous (BB) and wild-type (WW) of Small Tail Han sheep. This study identified differentially expressed miRNAs (DEMs) related to re-production. Of these, 10, 4, 10, and 4 were differentially expressed (DE) between BB_F and BB_L, WW_F and WW_L, BB_F and WW_F, and BB_L and WW_L, respectively. Bioinformatics analysis revealed the enrichment of the target genes of these DEMs in multiple GO terms linked to animal re-productive processes and KEGG signaling pathways. The follicular phase and luteal phase show significant enrichment in multiple pathways closely related to cell communication and signal transduction, including the MAPK signaling pathway, neuroactive ligand-receptor interaction, and the cAMP signaling pathway. In comparisons of genotypes, the calcium signaling pathway, the cAMP signaling pathway, and the MAPK signaling pathway are enriched. The miRNA-mRNA co-expression network indicates that novel121 and oar-miR-10b may regulate CUL4B and ZFAND5, respectively, playing crucial roles in sheep reproduction. Dual luciferase reporter gene assays hinted at a potential targeting relationship between novel-121 and DNMT3A. These findings elucidate the impact of pituitary miRNAs on follicular development influenced by FecB gene mutation, providing valuable insights into sheep breeding.

Transcriptome Analysis Reveals Differentially Expressed circRNAs Associated with Fecundity in Small-Tail Han Sheep Thyroid with Different FecB Genotypes

Litter size is an economically important trait in sheep, and it is a complex trait controlled by multiple genes in multiple organs. Among them, the regulation of lamb number trait by the thyroid gland is a very important part. However, the molecular mechanisms of the thyroid gland in sheep reproduction remain unclear. Here, RNA-seq was used to detect transcriptome expression patterns in the thyroid gland between follicular phase (FP) and luteal phase (LP) in FecB BB (MM) and FecB ++ (ww) STH sheep, respectively, and to identify differentially expressed circRNAs (DECs) associated with reproduction. Bioinformatic analysis of the source genes of these DECs revealed that they can be enriched in multiple signaling pathways involved in the reproductive process of animals. We found that the source genes of these DECs, such as GNAQ, VEGFC, MAPK1, STAT1, and HSD17B7, may play important roles in the reproductive process of animals. To better understand the function of these DECs, we constructed circRNA-miRNA co-expression networks. Dual luciferase reporter assays suggested that a ceRNA regulatory mechanism between circ_0003259-oar-miR-133-TXLNA and circ_0012128-oar-miR-370-3p-FGFR1 may hold. All of these DEC expression profiles in the thyroid gland provide a novel resource for elucidating the regulatory mechanisms underlying STH sheep prolificacy.