Control of juvenile hormone biosynthesis in Bombyx mori: Cloning of the enzymes in the mevalonate pathway and assessment of their developmental expression in the corpora allata

Kinjoh, Terunori; Kaneko, Yu; Itoyama, Kyo; Mita, Kazuei; Hiruma, Kiyoshi; Shinoda, Tetsuro

doi:10.1016/j.ibmb.2007.03.008

Cited by 151 publications

(196 citation statements)

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“…Transcriptional regulation of JH biosynthetic enzymes plays a key role in the control of JH synthesis (8,19). Changes in AaSDR-1 mRNA levels in the CA are consistent with the role of this gene in JH synthesis.…”

Section: Aasdr-1 Efficiently Oxidizes Farnesol To Farnesalsupporting

confidence: 64%

“…AaSDR-1 mRNA and its closest ortholog in D. melanogaster (CG 1386) were undetectable in pupae of mosquitoes and fruit flies (29). It has been described that transcription of genes coding for JH synthetic enzymes is suppressed or significantly reduced during pupal development to guarantee a successful completion of metamorphosis (8,19,30). On the other hand, JH synthesis in adult mosquitoes is a very dynamic and nutrient-dependent process (31).…”

Section: Aasdr-1 Efficiently Oxidizes Farnesol To Farnesalmentioning

confidence: 99%

“…In Orthoptera and Dictyoptera epoxidation follows methylation (3,6) and this is also the case in mosquitoes (2,7). The conservation of the mevalonate pathway between vertebrates and insects has made possible the molecular cloning of the enzymes involved in the early steps of JH biosynthesis (8), but this option is not available for the later, JH-specific steps. Using molecular approaches, the last two enzymes of the pathway, the P450 epoxidase and JHAMT were recently characterized (9,10).…”

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confidence: 99%

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NADP ⁺ -dependent farnesol dehydrogenase, a corpora allata enzyme involved in juvenile hormone synthesis

Mayoral

Nouzová

Navare

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

107

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The synthesis of juvenile hormone (JH) is an attractive target for control of insect pests and vectors of disease, but the minute size of the corpora allata (CA), the glands that synthesize JH, has made it difficult to identify important biosynthetic enzymes by classical biochemical approaches. Here, we report identification and characterization of an insect farnesol dehydrogenase (AaSDR-1) that oxidizes farnesol into farnesal, a precursor of JH, in the CA. AaSDR-1 was isolated as an EST in a library of the corpora allata-corpora cardiaca of the mosquito Aedes aegypti. The 245-amino acid protein presents the typical short-chain dehydrogenase (SDR) Rossmann-fold motif for nucleotide binding. This feature, together with other conserved sequence motifs, place AaSDR-1 into the ''classical'' NADP ؉ -dependent cP2 SDR subfamily. The gene is part of a group of highly conserved paralogs that cluster together in the mosquito genome; similar clusters of orthologs were found in other insect species. AaSDR-1 acts as a homodimer and efficiently oxidizes C 10 to C15 isoprenoid and aliphatic alcohols, showing the highest affinity for the conversion of farnesol into farnesal. Farnesol dehydrogenase activity was not detected in the CA of newly emerged mosquitoes but significant activity was detected 24 h later. Real time PCR experiments revealed that AaSDR-1 mRNA levels were very low in the inactive CA of the newly emerged female, but increased >30-fold 24 h later during the peak of JH synthesis. These results suggest that oxidation of farnesol might be a rate-limiting step in JH III synthesis in adult mosquitoes.mosquito ͉ Aedes ͉ farnesal ͉ insect

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Section: Aasdr-1 Efficiently Oxidizes Farnesol To Farnesalsupporting

confidence: 64%

Section: Aasdr-1 Efficiently Oxidizes Farnesol To Farnesalmentioning

confidence: 99%

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confidence: 99%

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NADP ⁺ -dependent farnesol dehydrogenase, a corpora allata enzyme involved in juvenile hormone synthesis

Mayoral

Nouzová

Navare

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

107

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“…Recently, JH synthesis was observed in female adults of B. mori but not in male adults (Kinjoh et al, 2007). Bommo-HMGR (Fig.…”

Section: Bommo-hmgr and -Jhamt Expression In Ca Of B Mori Pharate Admentioning

confidence: 93%

“…At the beginning of the fifth instar, the expression of JHAMT in CA reaches the highest level then declines rapidly to undetectable by day 4 and remains so until pupation (Shinoda and Itoyama, 2003). During the period of adult emergence, a high expression level of JHAMT was also observed in female CA (Kinjoh et al, 2007). The expression pattern of JHAMT during the postembryonic development exhibits a good correlation with JH synthesis by CA (Niimi and Sakurai, 1997).…”

Section: Introductionmentioning

confidence: 89%

Juvenile hormone acid methyl transferase is a key regulatory enzyme for juvenile hormone synthesis in the Eri silkworm, Samia cynthica ricini

Sheng

Cao

et al. 2008

Arch Insect Biochem Physiol

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During the period of adult emergence in the Eri silkworm, Samia cynthia ricini, the corpora allata (CA) are apparently reactivated in females, but not males. This creates a significant sexual dimorphism in juvenile hormone (JH) synthesis by CA. To determine the underlying molecular mechanisms in this process, we cloned cDNAs of two enzymes involved in the JH synthesis pathway: 3-hydroxy-3-methylglutaryl CoA reductase (HMGR) and juvenile hormone acid methyl transferase (JHAMT). Both Samcri-HMGR and -JHAMT mRNAs were detected in CA almost exclusively. However, their expression patterns were different from each other. During the period of adult emergence, Samcri-HMGR was expressed in CA at a constantly high level suggesting it plays little role for the regulation of JH synthesis. In contrast, the patterns of both Samcri-JHAMT mRNA level and enzyme activity were closely correlated with the patterns of JH synthesis, CA reactivation, and sexual dimorphism of JH synthesis. In addition, JHAMT mRNA levels were paralleled JH synthesis in the fifth-instar larvae of S. cynthia ricini and the pharate adults of the silkworm Bombyx mori. We infer from these results that JHAMT is a key regulatory enzyme for JH synthesis in the Eri silkworm.

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DECREASED JH BIOSYNTHESIS IS RELATED TO PRECOCIOUS METAMORPHOSIS IN RECESSIVE TRIMOLTER (rt) MUTANTS OF THE SILKWORM, Bombyx mori

Tsai

2012

Arch Insect Biochem Physiol

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In recessive trimolter (rt) mutants of the silkworm, Bombyx mori, that have four larval instars rather than five larval instars of normal B. mori, a decrease after a small increase in the hemolymph ecdysteroid titer during the early stages of the last (fourth) larval instar appeared to be a prerequisite for larvae to undergo precocious metamorphosis. The present study was carried out to investigate the possible mechanism underlying this decrease in the ecdysteroid titer. It was found that juvenile hormone (JH) biosynthetic activity of the corpora allata (CA) increased during the first day of the last larval instar, but its absolute JH biosynthesis activity was relatively lower compared to that of normal fourth-instar larvae in tetramolters. This lowered JH biosynthetic activity appeared to be related to a decrease in prothoracic gland ecdysteroidogenesis during the second day of the last instar, because hydroprene application prevented this decrease in prothoracic gland ecdysteroidogenesis, leading to the induction of a supernumerary larval molt. The in vitro incubation of prothoracic glands with hydroprene showed that hydroprene did not directly exert its action on prothoracicotropic hormone (PTTH) release. Further study showed that the application of hydroprene enhanced the competency of the glands to respond to PTTH. From these results, it was supposed that the lowered JH biosynthesis of the CA during the first day of last instar in rt mutants was related to decreased ecdysteroidogenesis in the prothoracic glands during the second day, thus playing a role in leading to precocious metamorphosis.

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Control of juvenile hormone biosynthesis in Bombyx mori: Cloning of the enzymes in the mevalonate pathway and assessment of their developmental expression in the corpora allata

Cited by 151 publications

References 47 publications

NADP ⁺ -dependent farnesol dehydrogenase, a corpora allata enzyme involved in juvenile hormone synthesis

NADP ⁺ -dependent farnesol dehydrogenase, a corpora allata enzyme involved in juvenile hormone synthesis

Juvenile hormone acid methyl transferase is a key regulatory enzyme for juvenile hormone synthesis in the Eri silkworm, Samia cynthica ricini

DECREASED JH BIOSYNTHESIS IS RELATED TO PRECOCIOUS METAMORPHOSIS IN RECESSIVE TRIMOLTER (rt) MUTANTS OF THE SILKWORM, Bombyx mori

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Control of juvenile hormone biosynthesis in Bombyx mori: Cloning of the enzymes in the mevalonate pathway and assessment of their developmental expression in the corpora allata

Cited by 151 publications

References 47 publications

NADP + -dependent farnesol dehydrogenase, a corpora allata enzyme involved in juvenile hormone synthesis

NADP + -dependent farnesol dehydrogenase, a corpora allata enzyme involved in juvenile hormone synthesis

Juvenile hormone acid methyl transferase is a key regulatory enzyme for juvenile hormone synthesis in the Eri silkworm, Samia cynthica ricini

DECREASED JH BIOSYNTHESIS IS RELATED TO PRECOCIOUS METAMORPHOSIS IN RECESSIVE TRIMOLTER (rt) MUTANTS OF THE SILKWORM, Bombyx mori

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NADP ⁺ -dependent farnesol dehydrogenase, a corpora allata enzyme involved in juvenile hormone synthesis

NADP ⁺ -dependent farnesol dehydrogenase, a corpora allata enzyme involved in juvenile hormone synthesis