In silico characterization of the neuropeptidome of the Western black widow spider Latrodectus hesperus

• The first peptidome for a member of the Araneae (true spiders) was deduced.
• Latrodectus hesperus transcripts encoding 23 peptide families were identified.
• The structures of 216 mature peptides were predicted, most of which are novel.
• Atypical, FLP, NPF, sulfakinin, orcokinin and TRP family members are described.
• These data provide a new resource for studying peptidergic control in the Araneae.

Technological advancements in high-throughput sequencing have resulted in the production/public deposition of an ever-growing number of arthropod transcriptomes. While most sequencing projects have focused on hexapods, transcriptomes have also been generated for members of the Chelicerata. One chelicerate for which a large transcriptome has recently been released is the Western black widow Latrodectus hesperus, a member of the Araneae (true spiders). Here, a neuropeptidome for L. hesperus was predicted using this resource. Thirty-eight peptide-encoding transcripts were mined from the L. hesperus transcriptome, with 216 distinct peptides predicted from the deduced pre/preprohormones. The identified peptides included members of the allatostatin A, allatostatin B, allatostatin C, allatotropin, bursicon α, bursicon β, CAPA/periviscerokinin/pyrokinin, CCHamide, corazonin, crustacean cardioactive peptide, crustacean hyperglycemic hormone/ion transport peptide, diuretic hormone 31, diuretic hormone 44, FMRFamide-like peptide (FLP), GSEFLamide, insulin-like peptide, neuropeptide F (NPF), orcokinin, proctolin, short neuropeptide F, SIFamide, sulfakinin and tachykinin-related peptide (TRP) families. Of particular note were the identifications of a carboxyl (C)-terminally extended corazonin, FLPs possessing –IMRFamide, –MMYFamide, and –MIHFamide C-termini, a NPF and a sulfakinin each ending in –RYamide rather than –RFamide, a precursor whose orcokinins include C-terminally amidated isoforms, and a collection of TRPs possessing –FXPXLamide rather than the stereotypical –FXGXLamide C-termini. The L. hesperus peptidome is by far the largest thus far published for any member of the Chelicerata. Taken collectively, these data serve as a reference for future neuropeptide discovery in the Araneae and provide a foundation for future studies of peptidergic control in L. hesperus and other spiders.