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The Widespread Impact of Mammalian MicroRNAs on mRNA Repression and Evolution
Kyle Kai-How Farh, Andrew Grimson, Calvin Jan, Benjamin P. Lewis, Wendy K. Johnston, Lee P. Lim, Christopher B. Burge and David P. Bartel
New Series, Vol. 310, No. 5755 (Dec. 16, 2005), pp. 1817-1821
Published by: American Association for the Advancement of Science
Stable URL: http://www.jstor.org/stable/3843017
Page Count: 5
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Thousands of mammalian messenger RNAs are under selective pressure to maintain 7-nucleotide sites matching microRNAs (miRNAs). We found that these conserved targets are often highly expressed at developmental stages before miRNA expression and that their levels tend to fall as the miRNA that targets them begins to accumulate. Nonconserved sites, which outnumber the conserved sites 10 to 1, also mediate repression. As a consequence, genes preferentially expressed at the same time and place as a miRNA have evolved to selectively avoid sites matching the miRNA. This phenomenon of selective avoidance extends to thousands of genes and enables spatial and temporal specificities of miRNAs to be revealed by finding tissues and developmental stages in which messages with corresponding sites are expressed at lower levels.
Science © 2005 American Association for the Advancement of Science