hpl-2 regulates dauer diapause. (a, b) hpl-2 regulates a subset of dauer-regulated genes. Venn diagrams show the intersection between hpl-2-regulated genes identified in this study and dauer-regulated genes . (c) hpl-2 mutants show an increased response to dauer pheromone. Crude pheromone extract  was added to plates at a concentration of 30 μl/ml. Data are the average of triplicate samples, each started with 40 to 50 eggs laid in situ at 20°C by three gravid adults that were subsequently removed. Plates were shifted to 25°C and scored for dauer formation after 48 hours. (d, e) hpl-2 enhances the dauer phenotype of mutants in the daf-2/IIS and TGF-β pathways. Synchronized populations of worms were obtained by letting single hermaphrodites lay eggs at 15°C. The mother was then removed and plates shifted to the indicated temperature for development. Dauers were scored 3 days after the removal of the mother for experiments at 20°C, 22°C and 25°C, and 4 days after the removal of the mother for experiments at 15°C. Data are the average of at least three independent experiments. (f) Tissue-specific rescue of dauer arrest phenotype of hpl-2;daf-2 animals. hpl-2;daf-2(e1370) transgenic animals expressing the hpl-2 cDNA under control of the indicated tissue-specific promoters were scored for ability to recover from dauer arrest as detailed in Materials and methods. Data are the average of at least three independent experiments with three independent lines for each construct.