Genome-Wide Identification of mRNAs, lncRNAs, and Proteins, and Their Relationship With Sheep Fecundity.

Chunxin Wang,Mingxin Zhang,Yunhui Zhao,Zhuo Zhao,Zhiyu Yuan,Jian Hou,Yujin Wu,Cuiling Wu

doi:10.3389/fgene.2021.750947

Abstract

The exploration of multiple birth-related genes has always been a significant focus in sheep breeding. This study aimed to find more genes and proteins related to the litter size in sheep. Ovarian specimens of Small Tail Han sheep (multiple births) and Xinji Fine Wool sheep (singleton) were collected during the natural estrus cycle. Transcriptome and proteome of ovarian specimens were analyzed. The transcriptome results showed that “steroid hormone biosynthesis” and “ovarian steroidogenesis” were significantly enriched, in which HSD17B1 played an important role. The proteome data also confirmed that the differentially expressed proteins (DEPs) were enriched in the ovarian steroidogenesis pathway, and the CYP17A1 was the candidate DEP. Furthermore, lncRNA MSTRG.28645 was highly expressed in Small Tailed Han sheep but lowly expressed in Xinji fine wool sheep. In addition, MSTRG.28645, a hub gene in the co-expression network between mRNAs and lncRNAs, was selected as one of the candidate genes for subsequent verification. Expectedly, the overexpression and interference of HSD17B1 and MSTRG.28645 showed a significant effect on hormone secretion in granulosa cells. Therefore, this study confirmed that HSD17B1 and MSTRG.28645 might be potential genes related to the fecundity of sheep. It was concluded that both HSD17B1 and MSTRG.28645 were critical regulators in the secretion of hormones that affect the fecundity of the sheep.

Highlights

Small Tail Han sheep is famous for its early maturity, perennial estrus, and polyembryony
The concentration and trend of follicle-stimulating hormone (FSH), luteinizing hormone (LH), E2, and P4 in serum was used to indicate the difference of the main reproductive hormones between the two breeds of sheep
It was found that the content of FSH in Mult was higher than that in sheep with large follicles group (Sgl) sheep (Figure 1A)

Summary

Introduction

Small Tail Han sheep is famous for its early maturity, perennial estrus, and polyembryony. The average litter size of excellent Small Tail Han sheep is 3.2 per parturition (Yuan et al, 2019). Xinji fine-wool sheep is a new breed of fine-wool sheep bred in China in 2003 and is characterized by single birth. Both Small Tail Han sheep and Xinji fine-wool sheep have stable genetic characteristics. Sheep multiple births have always been one of the goals of sheep breeding. Understanding the molecular mechanism is essential for multiple births sheep breeding. Previous studies have shown that the prolificacy trait is quantitative and controlled by multiple genes (Tang et al, 2019; Yang et al, 2019; Esmaeili-Fard et al, 2021).

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Conclusion