Functional cooperation between multiple regulatory elements in the untranslated exon 1 stimulates the basal transcription of the human GnRH-II gene

Mol Endocrinol. 2003 Jul;17(7):1175-91. doi: 10.1210/me.2002-0418. Epub 2003 Mar 27.

Abstract

The wide distribution of GnRH-II and conservation of its structure over all vertebrate classes suggest that the neuropeptide possesses vital biological functions. Although recent studies have shown that the expression of the human GnRH-II gene is regulated by cAMP and estrogen, the molecular mechanisms governing its basal transcription remain poorly understood. Using the neuronal TE-671 and placental JEG-3 cells, we showed that the minimal human GnRH-II promoter was located between nucleotide -1124 and -750 (relative to the translation start codon) and that the untranslated exon 1 was important to produce full promoter activity. Two putative E-box binding sites and one Ets-like element were identified within the first exon, and mutational analysis demonstrated that these cis-acting elements functioned cooperatively to stimulate the human GnRH-II gene transcription. EMSAs, UV cross-linking, and Southwestern blot analyses indicated that the basic helix-loop-helix transcription factor AP-4 bound specifically to the two E-box binding sites, whereas an unidentified protein bound to the Ets-like element. The functional importance of AP-4 in controlling human GnRH-II gene transcription was demonstrated by overexpression of sense and antisense full-length AP-4 cDNAs. Taken together, our present data demonstrate a novel mechanism in stimulating basal human GnRH-II gene transcription mediated by cooperative actions of multiple regulatory elements within the untranslated first exon of the gene.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Line
  • DNA, Antisense
  • DNA, Complementary / genetics
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • E-Box Elements
  • Exons*
  • Gene Expression
  • Gonadotropin-Releasing Hormone / analogs & derivatives*
  • Gonadotropin-Releasing Hormone / genetics*
  • Gonadotropin-Releasing Hormone / metabolism
  • Helix-Loop-Helix Motifs
  • Humans
  • Molecular Sequence Data
  • Promoter Regions, Genetic
  • Regulatory Sequences, Nucleic Acid*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcription Initiation Site
  • Transcription, Genetic*
  • Untranslated Regions

Substances

  • DNA, Antisense
  • DNA, Complementary
  • DNA-Binding Proteins
  • Transcription Factors
  • Untranslated Regions
  • enhancer-binding protein AP-4
  • Gonadotropin-Releasing Hormone
  • LHRH, His(5)-Trp(7)-Tyr(8)-