DEpiFIG 5: Hormonal regulation of dauer arrest by hypodermal DAF-9 activity.
DAF-9 is an enzyme within in the biosynthentic pathway for dafachronic acid, the DAF-12/NHR ligand, and a major site for its function is in the hypodermis.
A. Illustration shows expression of daf-9 in the hypodermis in larvae committed to reproductive development but not in dauers. Grey-filled drawings indicate that daf-9 is expressed, while white-filled ones indicate daf-9 is not expressed.
B. When liganded, DAF-12 promotes reproductive development in target cells such as the somatic gonad. In the absence of ligand, DAF-12 complexed to the DIN-1 corepressor promotes dauer formation.