A T > G Mutation in the NR5A2 Gene Is Associated With Litter Size in Hu Sheep Through Upregulation of Promoter Activity by Transcription Factor MTF-1

Abstract

Nuclear receptor subfamily 5 group A member 2 (NR5A2), also referred to as LRH-1 or FTF, is an orphan nuclear hormone receptor that is involved in regulating embryonic development, ovarian granulosa cell differentiation, gonadal sex differentiation, and steroidogenesis in mammals. However, little is known about how NR5A2 regulates reproduction in sheep. In this study, we amplified the promoter sequence of NR5A2 and determined that its core promoter region ranged from -721 nt to -281 nt. A T > G polymorphism at -700 nt was detected in the core promoter region. Association analysis found that the litter sizes of Hu ewes at their second and average parities with genotype GG (2.20 ± 0.20 and 1.97 ± 0.06, respectively) were significantly higher than those of ewes with genotype TG (1.68 ± 0.10 and 1.74 ± 0.05, respectively) (p < 0.05) and TT (1.67 ± 0.10 and 1.62 ± 0.06, respectively) (p < 0.05). The litter size of Hu ewes at their third parity with genotype GG (2.10 ± 0.10) was significantly higher than that of ewes with genotype TT (1.56 ± 0.12) (p < 0.05). A luciferase assay showed that the -700G allele increased the luciferase activity relative to the -700T allele. Furthermore, the -700T > G polymorphism created a novel binding site for metal-regulatory transcription factor 1 (MTF-1). A competitive electrophoretic mobility shift assay confirmed that MTF-1 specifically bound with the G-type promoter of NR5A2. An overexpression experiment demonstrated that MTF-1 was involved in the alteration of NR5A2 transcription activity and further increased NR5A2 gene mRNA expression. Our findings revealed that the -700T > G polymorphism promoted NR5A2 expression due to the positive effects on NR5A2 gene transcription activity by MTF-1 and thereby increased fecundity in Hu sheep.

LRH-1 high expression in the ovarian granulosa cells of PCOS patients

“…A lot of studies have confirmed that PCOS is associated with an increased prevalence of dysglycemia [26]. Based on the discovery of elevated LRH-1 in PCOS patients, by analyzing the clinical characteristics of recruited patients in this study, we found that PCOS patients was associated with litter size in Hu sheep [31]. LRH-1 deficiency leaded to the compromising placental development and the death of fetal, illustrating it was necessary the presence of LRH-1 for pregnancy [11].…”

Effect of polymorphisms in the 5’-flanking sequence of MC1R on feather color in Taihang chickens

“…The T > G polymorphism in the promoter region of sheep NR5A2 located at −700 nt significantly affected the average litter size of ewes and created a new binding site for the transcription factor MTF-1 . The results showed that MTF-1 positively regulated the transcriptional activity of NR5A2 , which increased the expression of NR5A2 and improved the fecundity of Hu sheep ( Li et al, 2019 ). There is a transcription factor-binding site for GATA2 in the 5’-flanking sequence of chicken KLF7 .…”

Mechanisms of Oogenesis-Related Long Non-coding RNAs in Porcine Ovaries Treated With Recombinant Pig Follicle-Stimulating Hormone

“…In the last decade, a number of researches had reported that lncRNAs played important roles in the oogenesis and ovulation in ovaries among different species, including pigs, cattle, mice, and sheep ( 11 , 21 , 32 , 33 ). The present study is the first to report the transcriptome profiling of lncRNAs and mRNA in pig ovaries treated with rpFSH.…”

“…Many studies have found that numerous signaling pathways and regulatory mechanisms are taken part in the regulation of oogenesis and ovulation in animals ( 11 , 21 , 32 , 33 ). In the current study, we performed GO terms and KEGG pathways analysis to further identify the biological functions of the target genes of DE mRNAs and DE lncRNAs related to oogenesis and ovulation in pig ovaries.…”

“…The expression level of NR5A2 gene in ovary was positively correlated with estrogen content ( 40 ), and NR5A2 regulated porcine follicular estrogen secretion and granular cell apoptosis by targeting CYP19A1 and CYP11A1 genes ( 42 ). Moreover, the polymorphism of NR5A2 gene showed significant association with litter size in Hu sheep ( 33 ). Our analysis result showed that the mRNA expression level of NR5A2 in rpFSH treatment group was significantly higher ( P < 0.01) than that of the control group; thus, we inferred that the NR5A2 might play an important role in the oogenesis and estrogen secretion.…”