Developmental expression and hormonal regulation of the nuclear 29 kDa juvenile hormone‐binding protein in Manduca sexta larval epidermis

Abstract

AbstractWe have utilized a high specific activity photoaffinity analog of methoprene, [3H]‐methoprene diazoketone (MDK), to study the developmental expression and hormonal regulation of the 29 kDa juvenile hormone (JH)‐binding protein. The 29 kDa MDK‐binding protein was detected in the epidermis of the feeding 4th and 5th instar larvae but decreased in abundance during the molts to the 5th instar and the pupa. This protein was also detected in day 1 pupal epidermis. Culturing of day 2 5th instar larval integument in the presence of 2 × 10−6 M 20‐hydroxyecdysone (20HE) caused a threefold decrease in the 29 kDa MDK‐binding protein. Presence of 3 × 10−6 M JH I prevented this loss. Allatectomy of molting 4th instar larvae after the critical period for JH for a larval molt resulted in the absence of the 29 kDa MDK‐binding protein in epidermis isolated 25 hr later or from either day 1 5th instar larvae or day 1 pupae. Application of 5 μ of JH I or methoprene at the time of allatectomy and every 12 hr thereafter until dissection was necessary for the presence of this protein in day 1 5th instar larval epidermis. Application of 5 μg of JH I on the day of wandering and the next day caused the appearance of the 29 kDa MDK‐binding protein in the epidermis of day 1 pupae formed by allatectomized larvae.