Toxin Diversity Revealed by a Transcriptomic Study of Ornithoctonus huwena

Abstract

Spider venom comprises a mixture of compounds with diverse biological activities, which are used to capture prey and defend against predators. The peptide components bind a broad range of cellular targets with high affinity and selectivity, and appear to have remarkable structural diversity. Although spider venoms have been intensively investigated over the past few decades, venomic strategies to date have generally focused on high-abundance peptides. In addition, the lack of complete spider genomes or representative cDNA libraries has presented significant limitations for researchers interested in molecular diversity and understanding the genetic mechanisms of toxin evolution. In the present study, second-generation sequencing technologies, combined with proteomic analysis, were applied to determine the diverse peptide toxins in venom of the Chinese bird spider Ornithoctonus huwena. In total, 626 toxin precursor sequences were retrieved from transcriptomic data. All toxin precursors clustered into 16 gene superfamilies, which included six novel superfamilies and six novel cysteine patterns. A surprisingly high number of hypermutations and fragment insertions/deletions were detected, which accounted for the majority of toxin gene sequences with low-level expression. These mutations contribute to the formation of diverse cysteine patterns and highly variable isoforms. Furthermore, intraspecific venom variability, in combination with variable transcripts and peptide processing, contributes to the hypervariability of toxins in venoms, and associated rapid and adaptive evolution of toxins for prey capture and defense.

Intraspecific variations in Conus purpurascens injected venom using LC/MALDI-TOF-MS and LC-ESI-TripleTOF-MS

“…Therefore, the deep peptidomic analysis of any Conus species must include intraspecific variations. Peptidomic/venomic analysis that included intraspecific variations has been reported for snakes [43,44], scorpions [45], and spiders [46], where intraspecific venom variability, in combination with variable transcripts and peptide processing, is a determinant to produce hypervariability of toxins, a process which appears to be associated to a rapid and adaptive molecular evolution of toxins optimizing prey capture and defense. Conopeptides that were identified in at least one specimen are bolded; empty square indicates that the mass was detected Fig.…”

Molecular diversity and evolutionary trends of cysteine-rich peptides from the venom glands of Chinese spider Heteropoda venatoria

“…The construction of cDNA library with ESTs Sanger sequencing approach has been proved to be a rapid and reliable method for discovering new genes and obtaining data on the gene expression of CRPs in venom glands, which are characterized as multigenes displaying high similarity in part of their sequences [47] . In our group, second-generation sequencing technologies were applied to explore the diverse peptide toxins in venom of H. huwenum [48] and Latrodectus tredecimguttatus [49] , the sequencing assembly of which strongly relied on the ESTs Sanger sequencing data. Furthermore, the data from Sanger sequencing method usually include the information of 5' and 3' untranslated regions which are very important for evolutionary analysis [50] .…”

The Venom of Ornithoctonus huwena affect the electrophysiological stability of neonatal rat ventricular myocytes by inhibiting sodium, potassium and calcium current

“…As described in previous work, the venom of spider showed current inhibition on cardiac sodium channels, potassium channels and calcium channels [ 20 ]. The Chinese tarantula O.huwena is similar to the spider O. hainana in morphology, and the toxin peptides in their venom gland showed high sequence homology [ 32 , 33 ]. However, divergences of electrophysiological effect on cardiac ion channels were observed between two spider venom.…”