Characterization of circular RNA profiles of oviduct reveal the potential mechanism in prolificacy trait of goat in the estrus cycle

Abstract

The mammalian oviduct is functionally highly diverse during the estrus cycle. It provides a suitable milieu for oocyte maturation, sperm capacitation, fertilization, early embryo development and transportation. While there have been many studies of molecular mechanisms on the kidding number of goats, a systematic analysis by which the underlying circular RNAs (circRNAs) changes in the oviduct related to prolificacy traits is lacking. Herein, we present a comprehensive circRNA atlas of the oviduct among high-and low-fecundity goats in the follicular phase (FH vs. FL), luteal phase (LH vs. LL), and estrus cycle (FH vs. LH; FL vs. LL) to unravel their potential regulatory mechanisms in improving kidding number. We generated RNA sequencing data, and identified 4,078 circRNAs from twenty sampled Yunshang black goats. Many of these circRNAs are exon-derived and differentially expressed between each comparison group. Subsequently, eight differentially expressed (DE) circRNAs were validated by RT-qPCR, which was consistent with the RNA-seq data. GO and KEGG enrichment analyses suggested that numerous host genes of DE circRNAs were involved in the hormone secretion, gamete production, fertilization, and embryo development processes. The competing endogenous RNA (ceRNA) interaction network analysis revealed that 2,673 circRNA-miRNA-mRNA axes (including 15 DE circRNAs, 14 miRNAs, and 1,699 mRNAs) were formed, and several target genes derived from the ceRNA network were associated with oviduct functions and reproduction, including SMAD1, BMPR1B, IGF1, REV1, and BMP2K. Furthermore, might play important roles in reproduction. Finally, a novel circRNA, circIQCG, was identified as potentially involved in embryo development. Overall, our study provides a resource of circRNAs to understand the oviductal function and its connection to prolificacy trait of goats in the differentiation estrus cycle.

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

“…In addition, we also selected four differential components (oar-circ-0026172, oar-circ-0002134, oar-circ-0019011, and oar-circ-0021170) for looped detection to verify the results of RNA-seq. Briefly, the region containing the backsplice junction site of circRNA was amplified by reverse-transcription PCR (RT-PCR), and the RT-PCR product was subjected to Sanger sequencing [21].…”

“…CircRNAs have multiple functions and usually act as a sponge for related miRNAs [20]. In the study on the oviduct of high-fecundity Yunshang black goats, it was found that circIQCG can affect the expression of SMAD1 by sponging miR-145-5p, thereby promoting the activation of the TGF-β(transforming growth factor-β) pathway and affecting the fecundity of goats [21]. In addition, circRNAs can promote the transcription of source genes by interacting with U1 small ribonucleoproteins and RNA polymerase II [22].…”

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

“…Zhang et al [ 12 ] identified several differential circRNAs by RNA-seq of porcine oocyte nuclei and found that circARMC4 affects chromosome arrangement, first polar body extrusion and early embryonic development in porcine oocytes. In our laboratory, several circRNAs associated with sheep reproduction were identified by RNA-seq analysis of hypothalamic tissues from STH sheep [ 13 ] and oviductal tissues from Yunshang black goats [ 14 ] at different reproductive cycles. In addition, we performed RNA-seq analysis of the thyroid gland of sheep with different FecB genotypes STH in the follicular phase, which resulted in the identification of several differentially expressed lncRNAs and mRNAs that can be enriched in signaling pathways associated with reproduction in sheep [ 15 ].…”

Oviduct Transcriptomic Reveals the Regulation of mRNAs and lncRNAs Related to Goat Prolificacy in the Luteal Phase

“…For example, BMP15 , growth differentiation factor 9 ( GDF9 ), and bone morphogenetic protein receptor 1B ( BMPR1B ) are all prolificacy-related genes in goats [ 14 ]. In addition to these major genes in the whole-transcriptome sequencing, noncoding RNAs (ncRNAs) are also widely studied [ 15 , 16 , 17 ].…”