Sequence of the Hexameric Juvenile Hormone-binding Protein from the Hemolymph of Locusta migratoria

Ralph P Braun,Gerard R Wyatt

doi:10.1074/jbc.271.49.31756

Abstract

The cDNA for the hexameric hemolymph juvenile hormone-binding protein (JHBP) from the migratory locust has been cloned and sequenced. Antiserum raised against purified JHBP was used to identify clones in an expression library. The 4.3-kilobase JHBP mRNA codes for 668 amino acids (74.4 kDa) and contains 2 kilobases of 3'-untranslated region. The derived amino acid sequence reveals that locust JHBP represents a new group within the hexamerin family of arthropod proteins. JHBP appears to be more closely related to arthropod hemocyanins, the believed ancestors of the family, than to the other known insect hexamerins. The mRNA shows a high (89%) bias to codons ending in G or C and the codons ending in A or T are clustered and concentrated toward the 5' end, suggesting a mosaic gene structure. The recombinant bacterially expressed protein bound [3H]JH III with the same affinity as the protein from hemolymph. A truncated version of JHBP lacking 53 amino acids from the N terminus did not bind JH III. Hybridization analysis of fat body JHBP mRNA in locusts that had been treated with precocene and a JH analog did not give clear evidence for regulation by JH.

Highlights

Juvenile hormone (JH)1 regulates many diverse events in the life cycle of an insect [1, 2]
The hexameric juvenile hormone-binding protein (JHBP) from locusts, the JH-binding properties and tissue distribution of which have previously been studied (8 –11), has been cloned as cDNA and sequenced. This represents the first sequence for a non-lipophorin high molecular weight JH-binding protein, and one of the first hexamerin sequences from the relatively primitive exopterygote group of insects
The recognition of JH III by target cells is expected to be in the form of the JH III-JHBP complex, and JHBP is an important component of the JH signal [2]

Summary

Introduction

Juvenile hormone (JH)1 regulates many diverse events in the life cycle of an insect [1, 2]. The reactivity of the recombinant protein to JHBP antiserum, specific binding of JH III and identical N-terminal sequence to the JHBP protein purified from hemolymph, indicate that the jhbp clone represents the sequence of JHBP mRNA.

Results

Conclusion