PHOTOAFFINITY-LABELING OF JUVENILE-HORMONE EPOXIDE HYDROLASE AND JH-BINDING PROTEINS DURING OVARIAN AND EGG DEVELOPMENT IN MANDUCA-SEXTA

Developmental profiles of a membrane-associated 50 kDa juvenile hormon e epoxide hydrolase (JHEH) and a cytosolic 32 kDa juvenile hormone bin ding protein (JHBP) in the ovaries and eggs of Manduca sexta were obta ined using photoaffinity analogs of JHs. The 50 kDa JHEH was present a t a constant level in adult female ovaries, in eggs, and in first inst ar larvae. In contrast, the cytosolic 32 kDa JHBP was absent in pupae and increased significantly in the adult. The cytosolic 32 kDa JHBP in eggs had properties similar to the hemolymph 32 kDa JHBP in terms of size, isoelectric point, ligand specificity, and immunoreactivity. The level of hemolymph 32 kDa JHBP, however, was present throughout pupal and adult stages. The JH-specific esterase (JHE) activity in ovaries also increased in the adult, remained unchanged until oviposition, and decreased in eggs between days 1 and 2 after oviposition. These resul ts show an increase of cytosolic JHBP and JHE at the termination phase of vitellogenesis and oogenesis. Moreover, it appears that high JHE a nd JHEH activity in the embryo helps maintain a sufficiently low JH ti ter to circumvent inhibition of embryonic development. Finally, a hemo lymph 80 kDa protein, which was present in larvae and pupae but was ab sent in the newly eclosed adult female, was also specifically labeled by the JH photoaffinity analogs.