Circular RNAs are depleted of polymorphisms at microRNA binding sites.
BACKGROUND
Circular RNAs (circRNAs) are an abundant class of highly stable RNAs that can affect gene regulation by binding and preventing microRNAs (miRNAs) from regulating their messenger RNA (mRNA) targets. Mammals have thousands of circRNAs with predicted miRNA binding sites, but only two circRNAs have been verified as being actual miRNA sponges. As it is unclear whether these thousands of predicted miRNA binding sites are functional, we investigated whether miRNA seed sites within human circRNAs are under selective pressure.


RESULTS
Using SNP data from the 1000 Genomes Project, we found a significant decrease in SNP density at miRNA seed sites compared with flanking sequences and random sites. This decrease was similar to that of miRNA seed sites in 3' untranslated regions, suggesting that many of the predicted miRNA binding sites in circRNAs are functional and under similar selective pressure as miRNA binding sites in mRNAs.
Department of Cancer Research and Molecular Medicine and Department of Computer and Information Science, Norwegian University of Science and Technology, N-7489 Trondheim, Norway.
Laurent F
LF
Thomas
Department of Cancer Research and Molecular Medicine and Department of Computer and Information Science, Norwegian University of Science and Technology, N-7489 Trondheim, NorwayDepartment of Cancer Research and Molecular Medicine and Department of Computer and Information Science, Norwegian University of Science and Technology, N-7489 Trondheim, Norway.
Pål
P
Sætrom
D001665:Binding Sites; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D012313:RNA / Q000737:chemistry* / Q000378:metabolism; D000079962:RNA, Circular
D035683:MicroRNAs; D000079962:RNA, Circular; D012313:RNA