Figure 3. Modeling the Molting Timer. (A) We propose that interconnected positive and negative regulatory interactions among LIN-42, certain NRs, and let-7 family miRNAs compose a developmental oscillator that operates in the epidermis of juveniles and drives rhythmic molting cycles. This diagram depicts hypothetical molecular events that might occur in seam cells as animals enter and exit the larval molts. (B) The proposed molting timer may also regulate the rhythmic production of endocrine cues that affect animal behavior. Additional signals among the epidermis (orange), the nervous system (red), and body wall muscles (green) are expected to regulate lethargus and ecdysis. See text for additional information about this model.