Acta Veterinaria et Zootechnica Sinica ›› 2025, Vol. 56 ›› Issue (2): 666-678.doi: 10.11843/j.issn.0366-6964.2025.02.018

• Animal Biotechnology and Reproduction • Previous Articles     Next Articles

Bidirectional Promoter Regulate Transcriptional Expression of PRLR and SPEF2 in Chicken Embryonic Gonads

WANG Tao1(), WANG Qi2, DONG Jiaojiao1, WANG Dehe1, LI Lanhui1,*()   

  1. 1. College of Animal Science and Technology, Hebei Agricultural University, Baoding 071000, China
    2. Hebei Provincial Institute of Animal Husbandry and Veterinary Medicine, Baoding 071001, China
  • Received:2024-08-09 Online:2025-02-23 Published:2025-02-26
  • Contact: LI Lanhui E-mail:1905580765@qq.com;lanhuili13@163.com

Abstract:

This study aimed to reveal the bidirectional transcriptional regulation character of prolactin receptor gene (PRLR) and sperm flagellar protein 2 (SPEF2) in chicken embryonic gonads. The left and right gonads of 180 Dawu Jinfeng chicken embryos at 4 embryonic ages were collected, and each 3 samples mixing pools formed a repeat. Except for the complete degeneration of the right ovary of E21.5 hens, the other ipsilateral gonads of the same embryonic age and sex were divided into 14 groups. The expression changes of PRLR and SPEF2 in gonads of Dawujinfeng chickens at 4 embryonic ages (E12.5, E16.5, E18.5 and E21.5) were detected using real-time quantitative PCR (RT-qPCR). The transcription start sites (TSS) of the two genes were identified using rapid amplification of cDNA ends (5'RACE), their core promoter region was identified using dual luciferase reporter assay (DLRA). The methylation level in promoter region was detected using bisulfite genomic sequencing PCR (BSP). Results were as follows: The expression of PRLR in testis from E12.5 to E21.5 was higher than in ovary (P<0.05), while the expression of SPEF2 in ovary from E18.5 to E21.5 was higher than in testis (P<0.05). Among the 10 TSSs of PRLR, 5 had promoter activity, and all the 3 TSSs of SPEF2 had promoter activity. PA1 promoter region of PRLR and SC of SPEF2 exhibited the highest promoter activity (P<0.05), respectively. Further detection found that 565 bp of PA1 and 478 bp of SC in reverse complement had the highest promoter activity, respectively. The bidirectional promoter activity of 478 bp region was significantly higher than 565 bp (P<0.05), and both had significantly higher promoter activity for PRLR than for SPEF2 (P<0.05), which was in conformity with that the expression of PRLR was significantly higher than SPEF2 in chicken embryonic gonads at E12.5-E21.5 (P<0.05). That the methylation level of 443 bp CpG island in the bidirectional promoter region was significantly higher in E21.5 ovary than in testis (P<0.05), was in accordance with the higher expression of PRLR in testis. The methylation level of 159 bp CpG island in the first intron of SPEF2 was significantly higher in testis than in ovary (P<0.05), correlated with the higher expression of SPEF2 in ovary. In summary, the transcriptional expression of PRLR and SPEF2 in chicken embryonic gonads was regulated by bidirectional promoter with 478 bp core region, which had higher promoter activity for PRLR than SPEF2, and the expression of PRLR in gonad was higher than SPEF2. The methylation of the CpG island in BDP participated in regulating the transcriptional expression of PRLR, with ovary at E21.5 had higher methylation level, and PRLR was expressed lower in ovary. These results provided a theoretical basis for revealing transcriptional regulation mechanism of PRLR and SPEF2 in chicken gonadal development.

Key words: chicken, PRLR, SPEF2, bidirectional promoter, methylation

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