Does base-pairing strength play a role in microRNA repression?
- 1Department of Entomology, The Hebrew University, Rehovot 76100, Israel
- 2Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
Abstract
MicroRNAs (miRNAs) are short, single-stranded RNAs that silence gene expression by either degrading mRNA or repressing translation. Each miRNA regulates a specific set of mRNA “targets” by binding to complementary sequences in their 3′ untranslated region. In this study, we examined the importance of the base-pairing strength of the miRNA–target duplex to repression. We hypothesized that if base-pairing strength affects the functionality of miRNA repression, organisms with higher body temperature or that live at higher temperatures will have miRNAs with higher G/C content so that the miRNA–target complex will remain stable. In the nine model organisms examined, we found a significant correlation between the average G/C content of miRNAs and physiological temperature, supporting our hypothesis. Next, for each organism examined, we compared the average G/C content of miRNAs that are conserved among distant organisms and that of miRNAs that are evolutionarily recent. We found that the average G/C content of ancient miRNAs is lower than recent miRNAs in homeotherms, whereas the trend was inversed in poikilotherms, suggesting that G/C content is associated with temperature, thus further supporting our hypothesis. In the organisms examined, the average G/C content of miRNA “seed” sequences was higher than that of mature miRNAs, which was higher than pre-miRNA loops, suggesting an association between the degree of functionality of the sequence and its average G/C content. Our analyses show a possible association between the base-pairing strength of miRNA–targets and the temperature of an organism, suggesting that base-pairing strength plays a role in repression by miRNAs.
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Footnotes
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↵3 Corresponding author
E-mail heifetz{at}agri.huji.ac.il
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Article published online ahead of print. Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.032185.111.
- Received December 28, 2011.
- Accepted June 11, 2012.