Identification of Functional Single Nucleotide Polymorphisms in Porcine HSD17B14 Gene Associated with Estrus Behavior Difference between Large White and Mi Gilts.

Siyuan Gao,Qinglei Xu,Ruixin Tao,Jing Zhao,Xian Tong,Bo Zhou,Yanli Guo,Allan P Schinckel

doi:10.3390/biom10111545

Abstract

Steroid hormone levels are associated with estrous behavior, which affects timely mating and reproductive efficiency in pigs. 17β-hydroxysteroid dehydrogenase type 14 (HSD17B14) modulates steroid synthesis and metabolism. To identify the functional single nucleotide polymorphisms (SNPs) in the porcine HSD17B14 gene, ear tissues from Large White and Mi gilts were collected to extract genomic DNA. Variable lengths of truncated promoter of HSD17B14 gene were used to determine the promoter activity by a dual luciferase reporter system. The vector HSD17B14Phe or HSD17B14Val was transfected into porcine granulosa cells (GCs). The core promoter region was identified between −72 bp and −218 bp. Six of seven SNPs had significant differences of allele frequency between Large White and Mi gilts. The plasmids with the wild genotype AA of rs329427898 maintained a smaller fraction of promoter activity compared with the plasmids with the mutant genotype GG, while the plasmids with wild the genotype TT of rs319864566 had a greater promoter activity than the plasmids with the mutant genotype CC. A missense mutation (Phe73Val) caused changes in the structural dynamics and function of the HSD17B14 protein. The highly expressed HSD17B14Val degraded less estradiol into estrone, while the relatively lowly expressed HSD17B14Phe degraded more estradiol into estrone, suggesting the protein activity of HSD17B14Phe was greater than that of HSD17B14Val. Moreover, the HSD17B14Phe group has a greater apoptosis rate of porcine GCs. The HSD17B14 gene could been used as a candidate molecular marker for estrus behavior in pigs.

Highlights

The beginning of the estrous cycle occurs at the onset of estrus when the female animal is sexually receptive and is followed by the ovulation of follicles [1]
The synthesis of ovarian estrogen is regulated by luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the theca cell and granulosa cells (GCs) [10]
The promoter activity analyses suggest that the core promoter region of the porcine HSD17B14 gene is located between −972 bp and −218 bp from the initiation site of transcription

Summary

Introduction

The beginning of the estrous cycle occurs at the onset of estrus when the female animal is sexually receptive (known as in heat) and is followed by the ovulation of follicles [1]. Exploring the molecular regulatory mechanism of estrous behavior expression in sows and gilts could contribute to resolving the problem of anestrus and improving pig productivity [6]. Reproductive hormone secretion and physiological changes of gilts during the estrus cycle are regulated by multiple molecular interactions in reproductive related tissues, such as the hypothalamus, pituitary, ovary, oviduct, and endometrium [9]. The synthesis of ovarian estrogen is regulated by luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the theca cell and granulosa cells (GCs) [10]. During the growth and development of follicles, LH stimulates the theca to secrete testosterone, and under the stimulation of FSH, GCs convert testosterone to estradiol, namely, this process is termed “double cell dual-sex hormone effect mode” [10,11]

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