Conservation of ecdysis-triggering hormone signalling in insects

Žitňan, Dušan; Žitňanová, Inka; Spalovská, Ivana; Takáč, Peter; Park, Yoonseong; Me, Adams

doi:10.1242/jeb.00261

Cited by 85 publications

(59 citation statements)

References 34 publications

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“…However, it is important to recognize that wit mutants are defective only in the systemic, Tv-secreted form of FMRFamide. Although FMRFamide has a well-studied effect in modulating visceral and somatic muscle contraction (Nichols, 2003), no effect for FMRFamide in triggering eclosion has been uncovered (Fuse and Truman, 2002;Zitnan et al, 2003). In fact, FaRPs accumulate in a model of developmental arrest in Manduca (Zitnan et al, 1995).…”

Section: Discussionmentioning

confidence: 99%

Retrograde Gbb signaling through the Bmp type 2 receptor Wishful Thinking regulates systemic FMRFa expression inDrosophila

et al. 2003

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Amidated neuropeptides of the FMRFamide class regulate numerous physiological processes including synaptic efficacy at the Drosophilaneuromuscular junction (NMJ). We demonstrate here that mutations in wishful thinking (wit) a gene encoding a DrosophilaBmp type 2 receptor that is required for proper neurotransmitter release at the neuromuscular junction, also eliminates expression of FMRFa in that subset of neuroendocrine cells (Tv neurons) which provide the systemic supply of FMRFa peptides. We show that Gbb, a Bmp ligand expressed in the neurohemal organ provides a retrograde signal that helps specify the peptidergic phenotype of the Tv neurons. Finally, we show that supplying FMRFa in neurosecretory cells partially rescues the witlethal phenotype without rescuing the primary morphological or electrophysiological defects of wit mutants. We propose that Wit and Gbb globally regulate NMJ function by controlling both the growth and transmitter release properties of the synapse as well as the expression of systemic modulators of NMJ synaptic activity.

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Section: Discussionmentioning

confidence: 99%

Retrograde Gbb signaling through the Bmp type 2 receptor Wishful Thinking regulates systemic FMRFa expression inDrosophila

et al. 2003

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“…e Inferred from immunostaining of the endocrine Inka cells with the anti-myomodulin (MM) antiserum (Hewes et al, 2003). This antiserum likely cross-reacts with ETH, since both peptides share a PRL-amide C-terminal motif (Zitnan et al, 2003). f For reviews see (Hewes and Taghert, 2001;Vanden Broeck, 2001 …”

Section: Fly Strains and Genetic Manipulationsmentioning

confidence: 99%

Transcriptional regulation of neuropeptide and peptide hormone expression by theDrosophila dimmedandcryptocephalgenes

Gauthier

Hewes

2006

Journal of Experimental Biology

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SUMMARY The regulation of neuropeptide and peptide hormone gene expression is essential for the development and function of neuroendocrine cells in integrated physiological networks. In insects, a decline in circulating ecdysteroids triggers the activation of a neuroendocrine system to stimulate ecdysis, the behaviors used to shed the old cuticle at the culmination of each molt. Here we show that two evolutionarily conserved transcription factor genes, the basic helix-loop-helix (bHLH) gene dimmed (dimm)and the basic-leucine zipper (bZIP) gene cryptocephal (crc),control expression of diverse neuropeptides and peptide hormones in Drosophila. Central nervous system expression of three neuropeptide genes, Dromyosuppressin, FMRFamide-related and Leucokinin, is activated by dimm. Expression of Ecdysis triggering hormone (ETH) in the endocrine Inka cells requires crc; homozygous crc mutant larvae display markedly reduced ETH levels and corresponding defects in ecdysis. crcactivates ETH expression though a 382 bp enhancer, which completely recapitulates the ETH expression pattern. The enhancer contains two evolutionarily conserved regions, and both are imperfect matches to recognition elements for activating transcription factor-4 (ATF-4), the vertebrate ortholog of the CRC protein and an important intermediate in cellular responses to endoplasmic reticulum stress. These regions also contain a putative ecdysteroid response element and a predicted binding site for the products of the E74 ecdysone response gene. These results suggest that convergence between ATF-related signaling and an important intracellular steroid response pathway may contribute to the neuroendocrine regulation of insect molting.

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“…In some early experiments, rabbit anti-myomodulin (kindly provided by K. Weiss, Mt. Sinai School of Medicine, New York, NY) , which cross-reacts with ETH (Zitnan et al, 2003), was used to monitor ETH release (cf. O'Brien and Taghert, 1998).…”

Section: Immunohistochemistrymentioning

confidence: 99%

Neuroendocrine Control of Larval Ecdysis Behavior inDrosophila: Complex Regulation by Partially Redundant Neuropeptides

Clark¹,

Campo²,

Ewer³

2004

J. Neurosci.

109

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To complete each molting cycle, insects display a stereotyped sequence of behaviors to shed the remains of the old cuticle. These behavioral routines, as well as other related physiological events, are critical for proper development and are under the control of several neuropeptides. Their correct deployment and concatenation depends on the complex actions and interactions among several peptide hormones: ecdysis triggering hormone (ETH), eclosion hormone (EH), and crustacean cardioactive peptide (CCAP). Numerous theories, some in conflict, have been proposed to define the functional hierarchies by which these regulatory factors operate. Here we use wild-type Drosophila and transgenic flies bearing targeted ablations of either EH or CCAP neurons, or ablations of both together, to reevaluate their roles. Consistent with findings in moths, our results suggest that EH and ETH affect the release of each other via a positive feedback, although ETH can also be released in the absence of EH. We show that EH and ETH both contribute to the air filling of the air ducts (trachea) of the next stage but that EH may play a primary role in this process. We present evidence that EH, whose actions have always been placed upstream of CCAP, may also regulate ecdysis independently of CCAP. Finally, we confirm that flies lacking EH neurons do not ecdyse prematurely when injected with ETH peptides. These findings are surprising and not easily explained by currently available hypotheses. We propose that important additional neuropeptides, and additional interactions between known regulators, contribute to the mechanisms underlying insect ecdysis behaviors.

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Conservation of ecdysis-triggering hormone signalling in insects

Cited by 85 publications

References 34 publications

Retrograde Gbb signaling through the Bmp type 2 receptor Wishful Thinking regulates systemic FMRFa expression inDrosophila

Retrograde Gbb signaling through the Bmp type 2 receptor Wishful Thinking regulates systemic FMRFa expression inDrosophila

Transcriptional regulation of neuropeptide and peptide hormone expression by theDrosophila dimmedandcryptocephalgenes

Neuroendocrine Control of Larval Ecdysis Behavior inDrosophila: Complex Regulation by Partially Redundant Neuropeptides

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