Polymorphism in the Alternative Donor Site of the Cryptic Exon of LHCGR: Functional Consequences and Associations with Testosterone Level

Sci Rep. 2017 Apr 3:7:45699. doi: 10.1038/srep45699.

Abstract

Selective splicing is a feature of luteinizing hormone receptor (LHCGR). A cryptic exon (LHCGR-exon 6A) was found to be derived from alternative splicing in intron 6 of the LHCGR gene, which including two transcripts LHCGR-exon 6A-long and LHCGR-exon 6A-short. We addressed the functional consequences of SNP rs68073206, located at the +5 position of an alternative 5' splice donor site, and observed its association with male infertility in the subjects with azoospermia, oligoasthenozoospermia and normozoospermia. The translation product of splicing variant LHCGR-exon 6A was expressed in the cytoplasm and exhibited no affinity with [125I]-hCG. No dominant negative effect was observed in cells co-expressed with LHCGR-exon 6A and wild-type LHCGR. The long transcript (LHCGR-exon 6A-long) was significantly elevated in the granulosa cells with G/G genotypes, which could be reproduced in vitro by mini-gene construct transfection. Genotyping analysis showed no association between rs68073206 and male infertility. However, this polymorphism was significantly associated with testosterone levels in normozoospermic subjects (n = 210). In conclusion, SNP rs68073206 in the splicing site of the cryptic exon 6A of the LHCGR gene affect the splicing pattern in the gene, which may play a role in the modulation of the LHCGR sensitivity in the gonads.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Base Sequence
  • Exons / genetics*
  • Female
  • Gene Frequency
  • Genotype
  • Humans
  • Infertility, Male / genetics
  • Infertility, Male / metabolism
  • Male
  • Odds Ratio
  • Polymorphism, Single Nucleotide*
  • RNA Splice Sites / genetics*
  • Receptors, LH / genetics*
  • Testosterone / metabolism*

Substances

  • RNA Splice Sites
  • Receptors, LH
  • Testosterone