Inhibition of translation in living eukaryotic cells by an RNA G-quadruplex motif.
Guanine-rich sequences can adopt intramolecular four-stranded structures, called G-quadruplexes. These motifs have been intensively investigated on the DNA level, but their overall biological relevance remains elusive. Only recently has research concerning the function of G-quadruplexes in RNAs commenced. Here, we demonstrate for the first time, that an RNA G-quadruplex structure inhibits translation in vivo in eukaryotic cells. We investigated the function of a highly conserved, thermodynamically stable RNA G-quadruplex in the 5'-UTR of the mRNA of the human Zic-1 zinc-finger protein. Using dual luciferase reporter assay, we demonstrate that the Zic-1 RNA G-quadruplex represses protein synthesis inside eukaryotic cells. Quantitative RT-PCR assays confirmed that the reduction of protein synthesis is due to regulation of the translation process and not a consequence of reduced transcription. Western blot analysis revealed that expression of Zic-1 is strongly reduced by a 73 nucleotides-long fragment of the UTR containing the G-quadruplex motif. These structures might add to the more recently discovered elements in untranslated regions of mRNAs that regulate their translation.
Arora
Amit
A
Institute for Chemistry and Biochemistry, Free University of Berlin, Berlin, Germany.
Dutkiewicz
Mariola
M
Scaria
Vinod
V
Hariharan
Manoj
M
Maiti
Souvik
S
Kurreck
Jens
J
D020121:5' Untranslated Regions / Q000737:chemistry* / Q000378:metabolism*; D001483:Base Sequence; D015153:Blotting, Western; D005786:Gene Expression Regulation; D015894:Genome, Human; D006367:HeLa Cells; D006801:Humans; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D013816:Thermodynamics; D014157:Transcription Factors / Q000235:genetics*
D020121:5' Untranslated Regions; D014157:Transcription Factors; C492123:ZIC1 protein, human