Repression of translation of human estrogen receptor alpha by G-quadruplex formation.
Tissue-specific expression of the human estrogen receptor alpha gene (ESR1) is achieved through multiple promoter sequences resulting in various mRNA transcripts encoding a common protein but differing in their 5'-untranslated region (5'-UTR). Many cancers are estrogen-sensitive with neoplastic growth stimulated through the estrogen receptor, a transcription factor that regulates developmental genes. We demonstrate that the human ESR1 gene is rich in potential quadruplex-forming sequences with 3 of 20 identified within exonic regions. In particular, we show using CD, UV, and NMR spectroscopy that a stable DNA G-quadruplex motif is formed within the exon C gene sequence. This motif, which PCR shows is transcribed in normal and neoplastic endometrium and in MCF-7 cells, forms a stable RNA quadruplex demonstrable by CD and UV analysis. Cloning the exon C G-quadruplex sequence upstream of a luciferase reporter gene caused a 6-fold reduction of enzymatic activity compared to a mutant sequence. We conclude that the exon C G-quadruplex motif is present in the 5'-UTR of the mRNA transcript, where it modulates the efficiency of translation.
Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
Graham D
GD
Balkwill
Kamila
K
Derecka
Thomas P
TP
Garner
Charlie
C
Hodgman
Anthony P F
AP
Flint
Mark S
MS
Searle
D020121:5' Untranslated Regions; D001483:Base Sequence; D001943:Breast Neoplasms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D004789:Enzyme Activation; D047628:Estrogen Receptor alpha / Q000096:biosynthesis* / Q000235:genetics*; D005260:Female; D054856:G-Quadruplexes; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet
D020121:5' Untranslated Regions; D047628:Estrogen Receptor alpha; D012333:RNA, Messenger