Molecular cloning and developmental expression of the gene encoding juvenile hormone esterase in the yellow-spotted longicorn beetle, Psacothea hilaris.
Juvenile hormone (JH) plays a key role in the regulation of growth, development, diapause and reproduction in insects. The regulation of JH titers in the insect body is therefore crucial throughout postembryonic development. One of the major pathways of JH metabolism is degradation by a highly selective enzyme, juvenile hormone esterase (JHE). We obtained a full-length cDNA encoding JHE in Psacothea hilaris (PhJHE). The complete PhJHE cDNA sequence is comprised of 1989 bp with an open reading frame of 1785 bp encoding 595 amino acid residues. The deduced protein sequence of PhJHE showed high homology with the Tenebrio molitor JHE (50% amino acid identity) and moderate homology with the Drosophila melanogaster JHE (34%). The PhJHE transcript was expressed mainly in the fat body. PhJHE transcript levels were low until day 3 of the 5th (final) larval instar, then steadily increased reaching a peak on day 13 (the prepupa stage), coinciding well with the peak hemolymph enzyme activity level. Sustained starvation of larvae after a period of feeding stimulated the expression of PhJHE mRNA while feeding the larvae with glucose downregulated its expression. These results are discussed with reference to the induction of precocious metamorphosis in this beetle by starvation.
Munyiri
Florence N
FN
Laboratory of Applied Entomology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan. fmunyiri@hotmail.com
Ishikawa
Yukio
Y
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D001517:Coleoptera / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D018076:DNA, Complementary / Q000737:chemistry; D006458:Hemolymph / Q000201:enzymology; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007605:Juvenile Hormones / Q000378:metabolism; D007814:Larva / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment
D018076:DNA, Complementary; D019476:Insect Proteins; D007605:Juvenile Hormones; D012333:RNA, Messenger; D002265:Carboxylic Ester Hydrolases; C038003:juvenile hormone esterase