Developmental regulation and functions of the expression of the neuropeptide corazonin in Drosophila melanogaster

Abstract

Although the corazonin gene (Crz) has been molecularly characterized, little is known concerning the function of this neuropeptide in Drosophila melanogaster. To gain insight into Crz function in Drosophila, we have investigated the developmental regulation of Crz expression and the morphology of corazonergic neurons. From late embryo to larva, Crz expression is consistently detected in three neuronal groups: dorso-lateral Crz neurons (DL), dorso-medial Crz neurons (DM), and Crz neurons in the ventral nerve cord (vCrz). Both the vCrz and DM groups die via programmed cell death during metamorphosis, whereas the DL neurons persist to adulthood. In adults, Crz is expressed in a cluster of six to eight neurons per lobe in the pars lateralis (DLP), in numerous neuronal cells in the optic lobes, and in a novel group of four abdominal ganglionic neurons present only in males (ms-aCrz). The DLP group consists of two subsets of cells having different developmental origins: embryo and pupa. In the optic lobes, we have detected both Crz transcripts and Crz promoter activity, but no Crz-immunoreactive products, suggesting a post-transcriptional regulation of Crz mRNA. Projections of the ms-aCrz neurons terminate within the ventral nerve cord, implying a role as interneurons. Terminals of the DLP neurons are found in the retrocerebral complex that produces juvenile hormone and adipokinetic hormone. Significant reduction of trehalose levels in adults lacking DLP neurons suggests that DLP neurons are involved in the regulation of trehalose metabolism. Thus, the tissue-, stage-, and sex-specific expression of Crz and the association of Crz with the function of the retrocerebral complex suggest diverse roles for this neuropeptide in Drosophila.

Peptidomics of Neuropeptidergic Tissues of the Tsetse FlyGlossina morsitans morsitans

“…This corresponds to findings in D. melanogaster where Crz is expressed in neurons in the brain that send projections to the CC and CA [57]. The expression pattern is very similar in other dipterans, such as Musca domestica and P. terraenovae [58,59].…”

Characterization, expression, and evolutionary aspects of Corazonin neuropeptide and its receptor from the House Fly, Musca domestica (Diptera: Muscidae)

“…In addition to DL and vCrz neurons, Crz expression was observed in a pair of neurons (designated as DM neurons) in the pars intercerebralis of the larval Drosophila brain (Choi et al, 2005;Lee et al, 2008). However, these cells are not detectable in M. domestica by both ISH and IHC, suggesting that this expression site is specific to Drosophila species.…”

“…In addition to this site, species-specific expression sites have also been found. Notably, Crz mRNA expression in numerous cells in the optic lobe medulla was observed only in Drosophila melanogaster (Choi et al, 2005;Lee et al, 2008).…”

Allatostatin-A neurons inhibit feeding behavior in adult Drosophila

“…We also investigated whether activation of AstA neurons could override an experimental manipulation that sensitizes flies to starvation. Activation of neurons expressing the neuropeptide corazonin (Crz) (39) has been reported to reduce both starvation resistance and triglyceride (fat) stores (40), suggesting that it decreases energy reserves. Using an independently generated Crz-GAL4 line, we confirmed that activation of Crz-GAL4 neurons (using UAS-NaChBac) increased starvation sensitivity (Fig.…”