MicroRNAs (miRNAs), a large class of ~22 nucleotide non-coding RNAs (sRNAs) found in many plants and animals act to post-transcriptionally regulate gene expression. Approximately 3% of all known human genes encode miRNAs. Important functions for miRNAs in development, physiology and disease are emerging.
Here we propose to identify and characterize miRNA genetic networks by combining forward and reverse genetic approaches, experimental target identification, quantitative cell biology and computational analyses in C. elegans. We will focus our efforts on a set of 14 miRNAs that are conserved between C. elegans and mammals. Specifically, we will test genetic interactions between this panel of miRNA genes and all known genes in C. elegans using synthetic RNAi screens. Based on pilot studies we expect that these screens will identify direct targets of miRNAs as suppressors and genes acting redundantly with miRNA genes as enhancers. In parallel, we will use experimental approaches to identify the direct in vivo targets and upstream transcriptional regulators for these 14 miRNAs. Finally we will use a live assay for miRNA activity to measure the kinetics of the effects of miRNAs on the gene regulatory network.
To our knowledge this is the first study to use synthetic genetic screens to uncover genome-wide miRNA regulatory networks. This project is taking advantage of a number of recent advances in C. elegans technology. We will deliver a unique dataset to further our understanding of the biology of individual miRNAs in C. elegans, the characteristics of miRNA regulatory networks in C. elegans and more generally miRNA-dependent control in animals.