Abstract
Allatostatins (ASTs) are multifunctional neuropeptides that generally act in an inhibitory fashion. ASTs were identified as inhibitors of juvenile hormone biosynthesis. Juvenile hormone regulates insect metamorphosis, reproduction, food intake, growth, and development. Drosophila melanogaster RNAi lines of PheGlyLeu-amide-ASTs (FGLa/ASTs) and their cognate receptor, Dar-1, were used to characterize roles these neuropeptides and their respective receptor may play in behavior and physiology. Dar-1 and FGLa/AST RNAi lines showed a significant reduction in larval foraging in the presence of food. The larval foraging defect is not observed in the absence of food. These RNAi lines have decreased for transcript levels which encodes cGMP- dependent protein kinase. A reduction in the for transcript is known to be associated with a naturally occuring allelic variation that creates a sitter phenotype in contrast to the rover phenotype which is caused by a for allele associated with increased for activity. The sitting phenotype of FGLa/AST and Dar-1 RNAi lines is similar to the phenotype of a deletion mutant of an AST/galanin-like receptor (NPR-9) in Caenorhabditis elegans. Associated with the foraging defect in C. elegans npr-9 mutants is accumulation of intestinal lipid. Lipid accumulation was not a phenotype associated with the FGLa/AST and Dar-1 RNAi lines.
Highlights
In insects, three differing allatostatin (AST) peptide structures have been isolated that inhibit juvenile hormone (JH) biosynthesis
All three types of ASTs have been identified in D. melanogaster, but none have been identified as a regulator of JH biosynthesis [4,5,6,7]
Each Dar-1 and FGLa/AST RNAi line crossed to w1118 (Figure 1A, white bars) was compared DaGal4 crossed to w1118 (Figure 1A, black bar)
Summary
Three differing allatostatin (AST) peptide structures have been isolated that inhibit juvenile hormone (JH) biosynthesis. These include the FGLamide (FGLa)/ASTs, the W(X)6Wamide/ ASTs and the PISCF/ASTs. Each unique peptide structure appears to inhibit JH biosynthesis in select insect species [1,2,3]. FGLa/ASTs function to regulate gut contraction [11,12,13]. In D.melanogaster and other Diptera the FGLa/ASTs do not inhibit JH biosynthesis [7,14]and their function has yet to be determined. D. melanogaster FGLa/ASTs functionally interact with two galaninlike receptors Dar-1 and Dar-2 [4,15,16]. Dar-1 is primarily expressed in the larval CNS whereas Dar-2 appears to be expressed in the crop, midgut and hindgut [17]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
