Insulin stimulates ecdysteroidogenesis by prothoracic glands in the silkworm, Bombyx mori

Gu, Shi‐Hong; Lin, Ju-Ling; Lin, Pei‐Ling; Chen, Chien‐Hung

doi:10.1016/j.ibmb.2008.10.012

Cited by 71 publications

(63 citation statements)

References 50 publications

(78 reference statements)

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“…In addition, because we were unable to obtain meaningful blots from Bombyx prothoracic gland lysates with commercially available antitotal 4E-BP and anti-total S6K antibodies, signals obtained with the anti-a-tubulin antibody were used as loading controls. The Western blot analysis followed protocols as described in previous studies (Lin and Gu, 2007;Gu et al, 2009Gu et al, , 2010Gu et al, , 2011aGu et al, , 2011b.…”

Section: Western Blot Analysismentioning

confidence: 99%

“…For example, insulin/TOR/S6K signaling appears to be a critical pathway controlling neuronal growth and differentiation (Bateman and McNeill, 2004;McNeill et al, 2008). In B. mori, insulin/PI3K/Akt signaling is involved in prothoracic gland ecdysteroidogenesis (Gu et al, 2009). TOR gene transcription appears to be nutrientsensitive: starvation upregulates gene expressions of both TOR1 and TOR2 (Zhou et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

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TOR signaling is involved in PTTH-stimulated ecdysteroidogenesis by prothoracic glands in the silkworm, Bombyx mori

Yeh

Young

et al. 2012

Insect Biochemistry and Molecular Biology

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Section: Western Blot Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

TOR signaling is involved in PTTH-stimulated ecdysteroidogenesis by prothoracic glands in the silkworm, Bombyx mori

Yeh

Young

et al. 2012

Insect Biochemistry and Molecular Biology

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“…The increase in the level of ecdysteroid following the injection of insulin might be due to increased ecdysteroidogenesis by the PTG (Gu et al, 2009;Smith et al, 2014). In vitro studies on B. mori have revealed that insulin causes an increase in ecdysteroidogenesis in the PTG, but only when PTGs are isolated after day 4 of last instar larvae (Gu et al, 2009). However, it should be noted in their study a short incubation period of 8 h was used and that might have been insufficient to stimulate insulinmediated ecdysteroidogenesis.…”

Section: Discussionmentioning

confidence: 99%

“…The ecdysteroidogenesis in the PTG is also stimulated by an unidentified autocrine factor, as recorded in B. mori (Gu, 2007). A study on the stimulation of ecdysteroidogenesis by bombyxin and bovine insulin (Gu et al, 2009(Gu et al, , 2015 indicates that insulin-like peptides also regulate ecdysteroidogenesis. The stimulation of ecdysteroidogenesis in the PTG by insulin/insulin-like growth peptides/insulin signaling is also reported in other insects, such as Rhodnius prolixus and D. melanogaster (Vafopoulou & Steel, 1997;Caldwell et al, 2005;Colombani et al, 2005;Mirth et al, 2005).…”

Section: Introductionmentioning

confidence: 93%

A comprehensive study of the changes in ecdysteroid levels during the feeding phase of fifth instar larvae of the silkworm, Bombyx mori (Lepidoptera: Bombycidae)

Keshan¹,

Thounaojam²,

Kh.³

2015

Eur. J. Entomol.

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Abstract. The present study describes changes in haemolymph ecdysteroid levels during the feeding phase of fifth instar larvae of Bombyx mori. A small and sharp peak in ecdysteroid level was recorded on day 4 when larvae had already reached the critical weight (2.76 ± 0.11 g) for metamorphosis. Food deprivation of larvae from day 4 resulted in an increase in the ecdysteroid level. Injection of insulin in both 1 day (before reaching critical weight) and 4 day (after reaching critical weight) old fed larvae resulted in an increase in the ecdysteroid level. However, when deprived of food only the haemolymph ecdysteroid levels of 4 day old larvae respond to an injection of insulin. The hormone level was also increased by treating 1day old larvae with a juvenile hormone analogue, but again, like insulin, only the fed larvae were affected by this treatment. Neck-and thorax-ligated 4 day old larvae had decreased ecdysteroid levels compared to both fed and food deprived larvae. However, a significant increase in ecdysteroid level was recorded in both neck-and thorax-ligated larvae injected with insulin. The injection of 20-hydroxyecdysone into 4 day old larvae resulted in an increase in the level of this substance in the haemolymph of fed and food deprived larvae, but the level was significantly higher in neck-and thoraxligated la rvae. The data, thus, indicates that ecdysteroid levels vary both in relation to the critical weight of the larvae and its nutritional status, and insulin might also play an important role in regulating the level of ecdysteroid.

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“…AMPK is a member of the insulin, target of rapamycin (TOR) and cell death pathways (Kahn et al, 2005;Lippai et al, 2008), all of which are known to be important in the progression of development and molting in Lepidoptera (Lippai et al, 2008;Gu et al, 2009;Smith et al, 2014). In our transcriptome, Snf4Aγ was significantly downregulated in the later-emerging Z-strain compared with the earlier-emerging E-strain (FDR<0.001 on day 7) (Table 2; Fig.…”

Section: Gene Candidatesmentioning

confidence: 93%

Transcriptome profiling reveals mechanisms for the evolution of insect seasonality

Wadsworth

Dopman

2015

Journal of Experimental Biology

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Rapid evolutionary change in seasonal timing can facilitate ecological speciation and resilience to climate warming. However, the molecular mechanisms behind shifts in animal seasonality are still unclear. Evolved differences in seasonality occur in the European corn borer moth (Ostrinia nubilalis), in which early summer emergence in E-strain adults and later summer emergence in Z-strain adults is explained by a shift in the length of the termination phase of larval diapause. Here, we sample from the developmental time course of diapause in both strains and use transcriptome sequencing to profile regulatory and amino acid changes associated with timing divergence. Within a previously defined quantitative trait locus (QTL), we nominate 48 candidate genes, including several in the insulin signaling and circadian rhythm pathways. Genome-wide transcriptional activity is negligible during the extended Z-strain termination, whereas shorter E-strain termination is characterized by a rapid burst of regulatory changes involved in resumption of the cell cycle, hormone production and stress response. Although gene expression during diapause termination in Ostrinia is similar to that found previously in flies, nominated genes for shifts in timing are species specific. Hence, across distant relatives the evolution of insect seasonality appears to involve unique genetic switches that direct organisms into distinct phases of the diapause pathway through wholesale restructuring of conserved gene regulatory networks.

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Insulin stimulates ecdysteroidogenesis by prothoracic glands in the silkworm, Bombyx mori

Cited by 71 publications

References 50 publications

TOR signaling is involved in PTTH-stimulated ecdysteroidogenesis by prothoracic glands in the silkworm, Bombyx mori

TOR signaling is involved in PTTH-stimulated ecdysteroidogenesis by prothoracic glands in the silkworm, Bombyx mori

A comprehensive study of the changes in ecdysteroid levels during the feeding phase of fifth instar larvae of the silkworm, Bombyx mori (Lepidoptera: Bombycidae)

Transcriptome profiling reveals mechanisms for the evolution of insect seasonality

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