The Kim Lab studies how microRNAs and other classes of endogenous small noncoding RNAs regulate fundamental biological processes including neuronal and muscle function, germline development, transposon silencing, and oncogenic cell proliferation. The RNA interference (RNAi) and microRNA pathways regulate these diverse activities through sequence-specific gene silencing mechanisms mediated by small RNAs. For example, wild-type C. elegans (left) can be completely paralyzed by inactivating the expression of a muscle gene by RNAi (right). Using functional genomic, genetic, biochemical, cell biology, and computational strategies, our lab investigates the molecular mechanisms of small RNA biogenesis, target expression and silencing, and the biological functions of these emerging gene regulatory pathways in C. elegans as well as mammalian cell systems.