Identification, characterization and developmental expression of Halloween genes encoding P450 enzymes mediating ecdysone biosynthesis in the tobacco hornworm, Manduca sexta

Rewitz, Kim; Rybczynski, Robert; Warren, James T.; Gilbert, Lawrence I.

doi:10.1016/j.ibmb.2005.12.002

Cited by 97 publications

(81 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A. gambiae female does not depart from this picture, as they also produce 20E after a blood meal, as reported here. Furthermore, we have demonstrated that the enzymes involved in steroidogenesis are functionally conserved between A. gambiae and other insect species (21)(22)(23)(24)(25)(26)(27), and that ecdysteroids are produced and secreted by ovaries in Anopheles female mosquitoes, as described for A. aegypti (11). By contrast, the A. gambiae male mosquitoes appear so far unique among insects by their high production and storage of the steroid hormone 20E.…”

Section: Discussionmentioning

confidence: 83%

See 1 more Smart Citation

Anopheles gambiaemales produce and transfer the vitellogenic steroid hormone 20-hydroxyecdysone to females during mating

Pondeville

Maria

Jacques

et al. 2008

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

109

127

View full text Add to dashboard Cite

In female insects, the steroid hormone 20-hydroxyecdysone (20E) plays a major role in activating vitellogenesis, a process required for egg development. By contrast with vertebrates, production of large amounts of hormonal steroids has not been reported in adult male insects. In the present study, we analyzed steroidogenesis in both male and female adult of the malaria mosquito Anopheles gambiae and we found that A. gambiae male mosquitoes produce high amounts of the steroid hormone 20E. Importantly, we found that male accessory glands, but not testes, are the source of 20E. Moreover, this steroid hormone is stored in male accessory glands and delivered to females during mating. These findings suggest that male 20E may not act as a true male sex steroid, but more likely as an allohormone. Our results give new insights into speciesspecific physiological processes that govern the reproductive success of the malaria mosquito. This could thus lead to the identification of new target genes for manipulating male and/or female reproductive success, a promising way to reduce or eliminate mosquito population and therefore to control malaria transmission.allohormone ͉ ecdysteroids ͉ malaria ͉ male accessory glands ͉ mosquito

show abstract

Section: Discussionmentioning

confidence: 83%

“…1) provided the opportunity to investigate steroidogenesis in insect species of health or economic interest (21,22,(26)(27)(28). In the present study, we analyzed steroidogenesis in male and female A. gambiae during reproductive processes.…”

mentioning

confidence: 99%

Anopheles gambiaemales produce and transfer the vitellogenic steroid hormone 20-hydroxyecdysone to females during mating

Pondeville

Maria

Jacques

et al. 2008

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

109

127

View full text Add to dashboard Cite

show abstract

“…For example, insulin may have a role in stimulating the biosynthesis of enzymes involved in steroidogenesis, such as the Halloween genes. Transcripts of three of these genes have been characterized in M. sexta and have been shown to increase concomitantly with ecdysone titers (Rewitz et al, 2006). More recently one of these genes, Spook (Spo), was identified as a possible rate-limiting enzyme in the ecdysone biosynthetic pathway (Rewitz et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

“…Transcript levels of the target genes were normalized to the Manduca ribosomal gene rpL17A after correcting for differences in amplification efficiency (Pfaffl, 2001). Primer sequences for the ribosomal gene were as follows: forward 5'-TCCGCATCTCACTGGGTCT-3' and reverse 5'-CACGGCAATCACATACAGGTT-3' (Rewitz et al, 2006). Data was analyzed using a relative efficiency method described by Pfaffl (Pfaffl, 2001).…”

Section: Quantitative Real Time Pcr (Qpcr) Analysis Of Gene Expressionmentioning

confidence: 99%

“…100 ng of RNA from each pooled sample were reverse transcribed with gene specific primers. cDNA was analyzed using quantitative real time PCR and calculated using the Pfaffl method where the mean level of the V0 transcript was set to 1 and samples were normalized to the Manduca ribosomal protein rpL17A (Pfaffl, 2001;Rewitz et al, 2006). Bars are means + SE.…”

Section: Quantification Of 4ebp Proteinmentioning

confidence: 99%

See 1 more Smart Citation

Nutritional sensitivity of fifth instar prothoracic glands in the tobacco hornworm, Manduca sexta

Walsh

Smith

2011

Journal of Insect Physiology

View full text Add to dashboard Cite

The tobacco hornworm, Manduca sexta, has been a useful model for studying insect endocrinology. In M. sexta the majority of growth occurs during the fifth (final) larval stage. This growth is concurrent with endocrine changes that lead to a metamorphic molt. Past research has focused on the interplay of three growth hormones: juvenile hormone (JH), prothoracicotropic hormone (PTTH) and ecdysone, in regulating metamorphosis. The prothoracic glands, source of ecdysteroid molting hormones in insects, play a crucial role in coordinating growth. Insulin/insulin-like growth factor (IGF) signaling has been shown to regulate growth and secretion of steroidogenic tissues in both vertebrates and invertebrates, but it had yet to be well-characterized in M. sexta.In this dissertation I examined the role of insulin-directed growth in prothoracic glands during both normal larval development and in response to nutrient deprivation. In particular, I predicted that in response to a reduction in nutrients, the prothoracic glands would stop growing and ecdysone secretion would be reduced. Changes were assessed in actin abundance and in two nutritionally sensitive transcripts, insulin receptor and 4EBP.Actin abundance in prothoracic glands increased in the first four days of this stage, demo nstrating significant growth. Actin decreased in glands from starved larvae, indicating a cessation of growth. Both insulin receptor and 4EBP transcript were present during normal larval development. As expected, both insulin receptor and 4EBP transcript increased in response to starvation. This research was the first demonstration of insulin signaling in prothoracic glands of fifth instar M. sexta larvae, and revealed nutritional sensitivity of the prothoracic glands. 5Finally, ecdysone assays were conducted to determine the impact of nutrition on glandular secretory capacity. Starved larvae were unable to secrete as much ecdysone as fed controls. Injections of insulin were unable to rescue the ability of the glands to secrete high levels of ecdysone. This demonstrated that although insulin signaling was correlated with normal growth of the glands, insulin is not sufficient to impact the ability of the glands to secrete ecdysone in the absence of nutrie nts. 6 This thesis is dedicated to my parents,Robert and Angela Walsh, whose love and support made this dissertation possible.

show abstract

Inhibitory effect of molt‐inhibiting hormone on phantom expression in the Y‐organ of the kuruma prawn, Marsupenaeus japonicus

Asazuma

Nagata

Nagasawa

2009

Arch Insect Biochem Physiol

View full text Add to dashboard Cite

Molting in crustaceans is induced by ecdysteroids as in insects. The ecdysteroid titre in hemolymph is negatively regulated by molt-inhibiting hormone (MIH) that inhibits the secretion of ecdysteroids from the Y-organ, an ecdysteroid-producing gland of crustaceans, whereas little is known about the molecular mechanism of inhibition by MIH. Recently, the Halloween genes encoding cytochrome P450 monooxygenases were characterized as the steroidogenic enzymes in insects. To elucidate whether the ecdysteroidogenesis in the Y-organ is regulated by molt-inhibiting hormone (MIH), we analyzed the expression level of an orthologue of a member of the Halloween genes, phantom (Cyp306a1, phm), in the Y-organ of a decapod crustacean, Marsupenaeus japonicus. A cDNA encoding phm (Mj-phm) was cloned by degenerate PCR and 5'- and 3'-RACEs. The deduced amino acid sequence of Mj-phm showed about 40% identity to those of insect phm. The six motif sequences and the four substrate recognition sites were well conserved between Mj-PHM and other PHM. RT-PCR showed the specific expression of Mj-phm mRNA in the Y-organ. In addition, quantitative real-time PCR verified that the expression level of Mj-phm was significantly increased at the pre-molt stage and decreased after ecdysis. Furthermore, exposure of the Y-organ to MIH significantly decreased the Mj-phm expression level in vitro. These results indicate that the transcription of Mj-phm in the Y-organ may be regulated by the inhibitory mechanism of MIH of M. japonicus, which involves the consequent negative regulation of ecdysteroidogenesis at the transcriptional level.

show abstract

Identification, characterization and developmental expression of Halloween genes encoding P450 enzymes mediating ecdysone biosynthesis in the tobacco hornworm, Manduca sexta

Cited by 97 publications

References 39 publications

Anopheles gambiaemales produce and transfer the vitellogenic steroid hormone 20-hydroxyecdysone to females during mating

Anopheles gambiaemales produce and transfer the vitellogenic steroid hormone 20-hydroxyecdysone to females during mating

Nutritional sensitivity of fifth instar prothoracic glands in the tobacco hornworm, Manduca sexta

Inhibitory effect of molt‐inhibiting hormone on phantom expression in the Y‐organ of the kuruma prawn, Marsupenaeus japonicus

Contact Info

Product

Resources

About