Fig. 10 . A genetic model for the cessation of molting. We propose that let-7 and mir-84 act through the heterochronic pathway to repress key regulators of molting, including the conserved nuclear hormone receptor genes nhr-23 and nhr-25. let-7 and paralogous miRNAs might also target nhr-25 mRNA. Positive regulation is denoted by an arrowhead and negative regulation by a perpendicular line.