A sense-able microRNA.

In this issue of Genes & Development, Drexel and colleagues (pp. 2042-2047) present a beautiful example of how microRNAs (miRNAs) can regulate tissue-specific gene expression in a biologically relevant setting. They found that miR-791 is expressed in only three types of carbon dioxide (CO)-sensing neurons in Caenorhabditis elegans, and its primary function there seems to be repression of two target genes that interfere with the behavioral response to CO Interestingly, these two targets are broadly expressed across other tissues. Thus, restricted miRNA expression can lead to target repression in select tissues to promote distinct cellular physiologies.