The relationship between the variants in the 5'-untranslated regions of equine chorionic gonadotropin genes and serum equine chorionic gonadotropin levels

  • Liu, ShuQin (Equine Center, China Agricultural University) ;
  • Lian, Song (College of Animal Science and Technology, China Agricultural University) ;
  • Yang, YunZhou (Equine Center, China Agricultural University) ;
  • Fu, ChunZheng (Equine Center, China Agricultural University) ;
  • Ma, HongYing (Equine Center, China Agricultural University) ;
  • Xiong, ZhiYao (Equine Center, China Agricultural University) ;
  • Ling, Yao (College of Animal Science and Technology, China Agricultural University) ;
  • Zhao, ChunJiang (Equine Center, China Agricultural University)
  • Received : 2017.02.15
  • Accepted : 2017.03.30
  • Published : 2017.12.01


Objective: An experiment was conducted to study the association between the single nucleotide polymorphisms (SNPs) in 5'-untranslated regions (5'-UTR) of equine chorionic gonadotropin (eCG) genes and the serum eCG levels. Methods: SNPs in 5'-UTR of eCG genes were screened across 10 horse breeds, including 7 Chinese indigenous breeds and 3 imported breeds using iPLEX chemistry, and the association between the serum eCG levels of 174 pregnant Da'an mares and their serum eCG levels (determined with ELISA) was analyzed. Results: Four SNPs were identified in the 5'-UTR of the $eCG{\alpha}$ gene, and one of them was unique in the indigenous breeds. There were 2 SNPs detected at the 5' end of the $eCG{\beta}$ subunit gene, and one of them was only found in the Chinese breeds. The SNP g.39948246T>C at the 5'-UTR of $eCG{\alpha}$ was associated significantly with eCG levels of 75-day pregnant mare serum (p<0.05) in Da'an mares. Prediction analysis on binding sites of transcription factors showed that the g.39948246T>C mutation causes appearance of the specific binding site of hepatocyte nuclear factor 3 forkhead homolog 2 (HFH-2), which is a transcriptional repressor belonging to the forkhead protein family of transcription factors. Conclusion: The SNP g.39948246T>C at the 5'-UTR of $eCG{\alpha}$ is associated with eCG levels of 75-day pregnant mare serum (p<0.05).


  1. Cole HH, Hart GH. The potency of blood serum of mares in progressive stages of pregnancy in effecting the sexual maturity of the immature rat. Am J Physiol 1930;93:57-68.
  2. Cupps PT. Reproduction in domestic animals. Cambridge, MA, USA: Academic Press Inc; 1991. pp. 25-80.
  3. Bo GA, Baruselli PS. Synchronization of ovulation and fixed-time artificial insemination in beef cattle. Animal 2014;8(S1):144-50.
  4. Bo' GA, Baruselli PS, Moreno D, et al. The control of follicular wave development for self-appointed embryo transfer programs in cattle. Theriogenology 2002;57:53-72.
  5. Sales JN, Crepaldi GA, Girotto RW, Souza AH, Baruselli PS. Fixedtime AI protocols replacing eCG with a single dose of FSH were less effective in stimulating follicular growth, ovulation, and fertility in suckled-anestrus Nelore beef cows. Anim Reprod Sci 2011;124:12-18.
  6. Sa Filho MF, Ayres H, Ferreira RM, et al. Equine chorionic gonadotropin and gonadotropin-releasing hormone enhance fertility in a norgestomet-based, timed artificial insemination protocol in suckled Nelore (Bos indicus) cows. Theriogenology 2010;73:651-8.
  7. Baruselli PS, Reis EL, Marques MO, Nasser LF, Bo GA. The use of hormonal treatments to improve reproductive performance of anestrous beef cattle in tropical climates. Anim Reprod Sci. 2004;82-83:479-86.
  8. Cole HH, Goss H. The source of equine gonadotropin. In: Essays in biology, in honor of Herbert M. Evans. Berkeley and Los Angeles: University of California Press; 1943. pp. 107-19.
  9. Allen WR. Factors influencing pregnant mare serum gonadotrophin production. Nature 1969;223(5201):64-6.
  10. Lian S, Hou XL, Han HB, Han GC. Research advance in maternal level of eCG in pregnant mare. J Northeast Agric Univ 2010;41:157-60.
  11. Simoni M, Tüttelmann F, Michel C, et al. Polymorphisms of the luteinizing hormone/chorionic gonadotropin receptor gene: association with maldescended testes and male infertility. Pharmacogenet Genomics 2008; 18:193-200.
  12. Rull K, Nagirnaja L, Ulander VM, et al. Chorionic gonadotropin betagene variants are associated with recurrent miscarriage in two European populations. J Clin Endocrinol Metab 2008;93:4697-706.
  13. Yang WC, Tang KQ, Li SJ, Chao LM, Yang LG. Polymorphisms of the bovine luteinizing hormone/choriogonadotropin receptor (LHCGR) gene and its association with superovulation traits. Mol Biol Rep 2012;39:2481-7.
  14. Sambrook J, Fritsch EF, Maniatis T. Molecular cloning: a laboratory manual, 2nd. New York: Cold Spring Harbor Laboratory Press; 1989.
  15. Wade CM, Giulotto E, Sigurdsson S, et al. Genome sequence, comparative analysis, and population genetics of the domestic horse. Science 2009;326:865-7.
  16. Galet C, Le Bourhis CM, Chopineau M, et al. Expression of a single ${\beta}{\alpha}$ chain protein of equine LH/CG in milk of transgenic rabbits and its biological activity. Mol Cell Endocrinol 2001;174:31-40.
  17. Legardinier S, Klett D, Poirier JC, Combarnous Y, Cahoreau C. Mammalian-like nonsialyl complex-type N-glycosylation of equine gonadotropins in Mimic insect cells. Glycobiology 2005;15:776-90.
  18. Deng L. Secretory pattern, rapid analysis and raw blood harvest criterion for production of equine chorionic gonadotropin. Beijing, China: China Agriculture University; 2013.
  19. Latchman DS. Transcription factors: an overview. Int J Biochem Cell Biol 1997;29:1305-12.
  20. Zhang Y, Wang Z, Xiao H, et al. Foxd3 suppresses interleukin-10 expression in B cells. Immunology 2017;150:478-88.
  21. He GY, Hu JL, Zhou L, et al. The FOXD3/miR-214/MED19 axis suppresses tumour growth and metastasis in human colorectal cancer. Br J Cancer 2016;115:1367-78.