A nuclear juvenile hormone-binding protein from larvae of Manduca sexta: a putative receptor for the metamorphic action of juvenile hormone
Résumé
A 29-kDa nuclear juvenile hormone (JH)-binding protein from the epidermis of Manduca sexta larvae was purified by using the photoaffinity analog for JH II ([3H]epoxyhomofarnesyldiazoacetate) and partially sequenced. A 1.1-kb cDNA was isolated by using degenerate oligonucleotide primers for PCR based on these sequences. The cDNA encoded a 262-amino acid protein that showed no similarity with other known proteins, except for short stretches of the interphotoreceptor retinoid-binding protein, rhodopsin, and human nuclear protein p68. Recombinant baculovirus containing this cDNA made a 29-kDa protein that was covalently modified by [3H]epoxyhomofarnesyldiazoacetate and specifically bound the natural enantiomer of JH I (Kd = 10.7 nM). This binding was inhibited by the natural JHs but not by methoprene. Immunocytochemical analysis showed localization of this 29-kDa protein to epidermal nuclei. Both mRNA and protein are present during the intermolt periods; during the larval molt, the mRNA disappears but the protein persists. Later when cells become pupally committed, both the mRNA and protein disappear with a transient reappearance near pupal ecdysis. The properties of this protein are consistent with its being the receptor necessary for the antimetamorphic effects of JH.
Mots clés
- Sesquiterpenes/metabolism
- Tritium
- Polymerase Chain Reaction/methods
- Oligodeoxyribonucleotides
- Moths/growth & development/*metabolism/physiology
- Molecular Weight
- Molecular Sequence Data
- Biological/*physiology
- Metamorphosis
- Male
- Larva
- Kinetics
- Juvenile Hormones/metabolism
- Isomerism
- Insect Proteins
- Complementary/isolation & purification
- DNA
- Carrier Proteins/genetics/isolation & purification/*metabolism
- Base Sequence
- Animals
- Amino Acid Sequence