Molecular cloning of the gene for allatostatin family of neuropeptides from hybrid imported fire Ants (S. invicta x S. richteri)

Allatostatins (ASTs) are insect neuropeptides that inhibit juvenile hormone biosynthesis by the corpora allata. Despite the potential for application to pest control and management, only a limited number of these allatostatin neuropeptide genes have been characterized.

We report here the molecular characterization of a cDNA from hybrid imported fire ants (Solenopsis invicta x S. richteri) that encodes a precursor for the AST family of neuropeptides.

The cDNA AST sequence encoding pre-pro-AST in hybrid imported fire ants have been determined. To eliminate the risk of Taq-generated sequence errors, data were collected from both strands of the DNA, using independently amplified templates. The deduced sequence of the AST precursor contains all the appropriate signals for an exported protein capable of being processed into 8 amidated AST-type peptides. Northern hybridization analysis involving T7 and T3 probes showed hybridization of a fragment of cDNA spanning 850bp of the AST gene. The peptide sequences confirm the structure of five previously isolated ASTs and predict at least three new candidates. The Potential ASTs are largely consistent with the basic structural-core motif for AST activity of Tyr-Xaa-Phe-Gly-Leu-NH2. Immunoprecipitation conjugated with LC-MS were used for the quantification of the eight neuropeptides from ant hemolymph.