Neuron type-specific miRNA represses two broadly expressed genes to modulate an avoidance behavior in C. elegans

Abstract

Two broad gene classes are distinguished within multicellular organisms: cell type-specific genes, which confer particular cellular properties, and ubiquitous genes that support general cellular functions. However, certain socalled ubiquitous genes show functionally relevant cell type-specific repression. How such repression is achieved is poorly understood. MicroRNAs (miRNAs) are repressors, many of which are expressed with high cell type specificity. Here we showthat mir-791, expressed exclusively in the CO 2 -sensing neurons in Caenorhabditis elegans, represses two otherwise broadly expressed genes. This repression is necessary for normal neuronal function and behavior of the animals towardCO 2 . miRNA-mediated repression of broadly transcribed genes is a previously unappreciated strategy for cellular specialization.