RNA Pol II accumulates at promoters of growth genes during developmental arrest.

When Caenorhabditis elegans larvae hatch from the egg case in the absence of food, their development is arrested (L1 arrest), and they show increased stress resistance until food becomes available. To study nutritional control of larval development, we analyzed growth and gene expression profiles during L1 arrest and recovery. Larvae that were fed responded relatively slowly to starvation compared with the rapid response of arrested larvae to feeding. Chromatin immunoprecipitation of RNA polymerase II (Pol II) followed by deep sequencing showed that during L1 arrest, Pol II continued transcribing starvation-response genes, but the enzyme accumulated on the promoters of growth and development genes. In response to feeding, promoter accumulation decreased, and elongation and messenger RNA levels increased. Therefore, accumulation of Pol II at promoters anticipates nutritionally controlled gene expression during C. elegans development.