C. elegans is predicted to have 40 insulin-like genes1-3, many of which are expressed in overlapping subsets of sensory neurons and/or interneurons1,2,4,5. This suggests an intriguing possibility that insulin-like peptides (ILPs) convey the complexity of an animal''s environment to regulate its physiology. In this study, we show that specific ILPs act coordinately in response to distinct sensory cues to regulate the switch between two C. elegans developmental programs, reproductive growth versus dauer arrest. While one ILP,
ins-1, acts to ensure dauer arrest under harsh environments, two other ILPs,
daf-28 and
ins-6, act together to ensure reproductive development under good environmental conditions.
daf-28 plays a more primary role in inhibiting dauer entry, whereas
ins-6 has a more significant role in promoting dauer exit. Surprisingly, we also find that
ins-6 expression shifts from one set of sensory neurons to another at distinct steps of the developmental switch. Together our data suggest that specific ILPs generate precise responses to dauer-inducing pheromone signals and food-derived cues to regulate development through stimulus-regulated expression in different neurons. 1. Li, W. et al. Genes Dev 17 (7), 844-858 (2003). 2. Pierce, S. B. et al. Genes Dev 15 (6), 672-686 (2001). 3.
http://www.wormbase.org, release WS202, (2009). 4. Kodama, E. et al. Genes Dev 20 (21), 2955-2960 (2006). 5. Tomioka, M. et al. Neuron, 51 (5), 613-625 (2006).