Hirofumi TodaHirofumi Toda

The main goal of our lab is to understand the molecular and cellular mechanisms of sleep. Sleep is important and conserved in all animals from humans to insects. Yet, the function of sleep: why we need it, and the mechanisms of sleep: how it occurs remains largely mystery. In order to understand the mechanisms of sleep, we use fruit flies as a model system to tackle such questions because flies are fantastic genetic model organisms especially amenable for genetic screening. For example, to identify molecular factors that induces sleep, we carried out a genome-wide behavioral screen, evaluating over 12,000 fly lines, and found a novel sleep inducing factor named “nemuri”. Nemuri functions as an anti-microbial peptide that is essential for bacterial infection-induced sleep, suggesting Nemuri served as a key link between sleep and immunity. Our group combines genetic, biochemical, behavioral and imaging techniques to elucidate the mechanisms of how Nemuri functions inside neurons to induce sleep. Moreover, we aim to identify the mammalian homologue of nemuri through behavioral screening by expressing human candidate genes in fly brain. These studies will improve our understanding of how the sleepiness is represented inside the brain.