Ecdysone 20-hydroxylation inManduca sexta midgut: Kinetic parameters of mitochondrial and microsomal ecdysone 20-monooxygenases

Weirich, Günter F.; Williams, Virginia P.; Feldlaufer, Mark F.

doi:10.1002/(sici)1520-6327(1996)31:3<305::aid-arch5>3.0.co;2-w

Cited by 20 publications

(10 citation statements)

References 25 publications

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“…Thus ecdysteroid intermediates are shuttled between intracellular compartments during biosynthesis. In Manduca, E20MO activity is observed in both mitochondrial and microsomal fractions [21] and it is possible the Shd may reside in either of these locations [3,12] as demonstrated for some mammalian P450s [22,23].…”

Section: Ecdysteroidogenic Halloween P450s: M Sextamentioning

confidence: 91%

The Halloween genes code for cytochrome P450 enzymes mediating synthesis of the insect moulting hormone

Rewitz

Rybczynski

Warren

et al. 2006

Biochemical Society Transactions

156

130

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The developmental events occurring during moulting and metamorphosis of insects are controlled by precisely timed changes in levels of ecdysteroids, the moulting hormones. The final four sequential hydroxylations of steroid precursors into the active ecdysteroid of insects, 20E (20-hydroxyecdysone), are mediated by four cytochrome P450 (P450) enzymes, encoded by genes in the Halloween family. Orthologues of the Drosophila Halloween genes phantom (phm; CYP306A1), disembodied (dib; CYP302A1), shadow (sad; CYP315A1) and shade (shd; CYP314A1) were obtained from the endocrinological model insect, the tobacco hornworm Manduca sexta. Expression of these genes was studied and compared with changes in the ecdysteroid titre that controls transition from the larval to pupal stage. phm, dib and sad, which encode P450s that mediate the final hydroxylations in the biosynthesis of ecdysone, were selectively expressed in the prothoracic gland, the primary source of ecdysone during larval and pupal development. Changes in their expression correlate with the haemolymph ecdysteroid titre during the fifth (final) larval instar. Shd, the 20-hydroxylase, which converts ecdysone into the more active 20E, is expressed in tissues peripheral to the prothoracic glands during the fifth instar. Transcript levels of shd in the fat body and midgut closely parallel the enzyme activity measured in vitro. The results indicate that these Halloween genes are transcriptionally regulated to support the high biosynthetic activity that produces the cyclic ecdysteroid pulses triggering moulting.

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Section: Ecdysteroidogenic Halloween P450s: M Sextamentioning

confidence: 91%

The Halloween genes code for cytochrome P450 enzymes mediating synthesis of the insect moulting hormone

Rewitz

Rybczynski

Warren

et al. 2006

Biochemical Society Transactions

156

130

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“…The formation of 20-hydroxyecdysone is catalyzed by the enzyme system, ecdysone 20-monooxygenase (EC 1.14. In most insect species investigated so far, it was demonstrated that ecdysone 20monooxygenase activity fluctuated dramatically during postembryonic development, suggesting that ecdysone 20-monooxygenase plays a crucial role in postembryonic development (Feyereisen and Durst, 1980;Smith, 1985;Smith and Mitchell, 1986;Keogh et al, 1989;Chen et al, 1994;Weirich et al, 1996). In most insect species investigated so far, it was demonstrated that ecdysone 20monooxygenase activity fluctuated dramatically during postembryonic development, suggesting that ecdysone 20-monooxygenase plays a crucial role in postembryonic development (Feyereisen and Durst, 1980;Smith, 1985;Smith and Mitchell, 1986;Keogh et al, 1989;Chen et al, 1994;Weirich et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Ecdysone 20‐monooxygenase in eggs of the silkworm, Bombyx mori: Enzymatic properties and developmental changes

Horike¹,

Sonobe²

1999

Arch. Insect Biochem. Physiol.

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Ecdysone 20-monooxygenase in eggs of the silkworm Bombyx mori was characterized in relation to embryonic development. First, subcellular fractions were prepared by means of differential centrifugation, and analyzed using marker enzymes and antibodies against NADPH-cytochrome P450 reductase. It was demonstrated that most ecdysone 20-monooxygenase activity was associated with microsomes, and that there was little or no intrinsic mitochondrial ecdysone 20-monooxygenase. Next, conditions for the measurement of ecdysone 20-monooxygenase activity were established for the microsomal fraction, and changes in the enzyme activity were measured in diapause eggs and non-diapause eggs during early embryogenesis. It was demonstrated that enzyme activity in diapause eggs remained at a low level, while that in the non-diapause eggs increased from the gastrula stage. The increase in egg ecdysone 20-monooxygenase activity was prevented by actinomycin D and alpha-amanitin, suggesting that gene transcription is required for eliciting an increase in ecdysone 20-monooxygenase activity.

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“…The identified energy-linked reactions are driven by ETD, SD, or ATPD. The conversion of E to the active molting hormone, 20-HE, is catalyzed by the NADPH-preferring E-20M, a mitochondrial enzyme predominantly associated with the fifth larval stadium midgut and fatbody tissues of M. sexta and other insects (Smith 1985; Weirich 1997). A parallel relationship to NADPH-utilizing E-20M activity was demonstrated by recent biochemical characterization of NADH-NADP + and NADPH-NAD + transhydrogenations in both midgut and fatbody tissues.…”

Section: Discussionmentioning

confidence: 99%

“…A preference for NADPH-formation is necessary to facilitate the conversion of E to the active form of the hormone, 20-HE, a process critical for larval insect development (Weirich 1997; Mitchell et al 1999; Gilbert and Rewitz 2009). The effects of E on the mitochondrial transhy-drogenase could be part of a negative feedback mechanism serving as a pathway to supplement the required NADPH.…”

Section: Discussionmentioning

confidence: 99%

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Effects of 20-Hydroxyecdysone on the Reversible Mitochondrial Transhydrogenase in the Tobacco Hornworm,Manduca sexta

Vandock

Perregaux

Consiglio

2013

Journal of Insect Science

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The reversible, mitochondrial membrane-associated transhydrogenase from the midgut of Manduca sexta (L.) (Lepidoptera: Sphingidae) catalyzes hydride-ion transfer between NADP(H) and NAD(H). The effects of ecdysone and 20-hydroxyecdysone were evaluated and compared to both the NADH-NADP+ and NADPH-NAD+ transhydrogenations. In the direction of NADPH-formation, the developmentally significant transhydrogenations occur as non-energy- or energy-linked reactions. The energy-linked activity couples with either electron transport-dependent NADH or succinate utilization, or ATP hydrolysis by Mg++ -dependent ATPase. Upon the addition of ecdysone alone, all energy-linked reactions in the direction of NADPH formation exhibited a notable increase in activity level over the control reaction. The addition of 20-hydroxyecdysone yielded no significant increase in the activity of any of the transhydrogenations. Synergistic addition of both ecdysone and 20-hydroxyecdysone resulted in no significant effect on transhydrogenase activity. The results of this study make evident a relationship between the presence of ecdysone and 20-hydroxyecdysone on the overall activity of M. sexta midgut mitochondrial transhydrogenations. The potential mediation of the energy-linked mitochondrial transhydrogenations involved with NADPH synthesis through the developmental relationship of ecdysone and 20-hydroxyecdysone is considered.

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Ecdysone 20-hydroxylation inManduca sexta midgut: Kinetic parameters of mitochondrial and microsomal ecdysone 20-monooxygenases

Cited by 20 publications

References 25 publications

The Halloween genes code for cytochrome P450 enzymes mediating synthesis of the insect moulting hormone

The Halloween genes code for cytochrome P450 enzymes mediating synthesis of the insect moulting hormone

Ecdysone 20‐monooxygenase in eggs of the silkworm, Bombyx mori: Enzymatic properties and developmental changes

Effects of 20-Hydroxyecdysone on the Reversible Mitochondrial Transhydrogenase in the Tobacco Hornworm,Manduca sexta

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