High-Throughput Identification and Analysis of Novel Conotoxins from Three Vermivorous Cone Snails by Transcriptome Sequencing

Abstract

The venom of each Conus species consists of a diverse array of neurophysiologically active peptides, which are mostly unique to the examined species. In this study, we performed high-throughput transcriptome sequencing to extract and analyze putative conotoxin transcripts from the venom ducts of 3 vermivorous cone snails (C. caracteristicus, C. generalis, and C. quercinus), which are resident in offshore waters of the South China Sea. In total, 118, 61, and 48 putative conotoxins (across 22 superfamilies) were identified from the 3 Conus species, respectively; most of them are novel, and some possess new cysteine patterns. Interestingly, a series of 45 unassigned conotoxins presented with a new framework of C-C-C-C-C-C, and their mature regions were sufficiently distinct from any other known conotoxins, most likely representing a new superfamily. O- and M-superfamily conotoxins were the most abundant in transcript number and transcription level, suggesting their critical roles in the venom functions of these vermivorous cone snails. In addition, we identified numerous functional proteins with potential involvement in the biosynthesis, modification, and delivery process of conotoxins, which may shed light on the fundamental mechanisms for the generation of these important conotoxins within the venom duct of cone snails.

Structure, Function, and Therapeutic Potential of Marine Bioactive Peptides

“…The results are consistent with the hypothesis that certain worm-hunting Conus evolved δ-conotoxins that act to probably deter competitors in a defensive envenomation strategy [16]. To analyze putative conotoxin transcripts from the venom ducts of three vermivorous cone snails ( Conus caracteristicus , Conus generalis , and Conus quercinus ), high-throughput transcriptome sequencing was performed [17]. In total, 118, 61, and 48 putative conotoxins (across 22 superfamilies) were identified from the three Conus species, respectively [17].…”

“…To analyze putative conotoxin transcripts from the venom ducts of three vermivorous cone snails ( Conus caracteristicus , Conus generalis , and Conus quercinus ), high-throughput transcriptome sequencing was performed [17]. In total, 118, 61, and 48 putative conotoxins (across 22 superfamilies) were identified from the three Conus species, respectively [17]. Two comprehensive reviews included in this Special Issue deal with structural and functional analyses of cone snail toxins [18] and with computational studies on the conopeptides [19], providing a good overview of bioactive peptides from venoms of Conus species and their therapeutic potential.…”

Bioinformatics for Marine Products: An Overview of Resources, Bottlenecks, and Perspectives

“…Among these, RNA-seq produces a more detailed and quantitative overview of a transcriptome and the associated level of expression per gene, also providing—thanks to dedicated bioinformatics pipelines [105,106,107]—deep details on alternative splicing and allele-specific information [108], even in the absence of a reference sequenced genome (de novo transcriptome analyses). Compared to other transcriptome-based approaches such as ESTs and microarray analyses [109], the throughput of the RNA-seq techniques, together with lower experimental costs, allowed the spread of many projects that either accompanied the genome sequencing of many species to define their representative gene expression atlases [110] or independently allowed characterization of the transcriptome complement of a novel species exploiting a de novo assembly approach [111,112,113,114,115,116,117,118,119,120].…”

Diversity of Conopeptides and Their Precursor Genes of Conus Litteratus

“…There are about 800 species of Conus worldwide, which are distributed in tropical seas [1,2]. According to their diet habits, cone snails can be divided into three groups, vermivorous (V), molluscivorous (M), and piscivorous (P) species [3][4][5]. Although they move slowly, cone snails can prey on creatures with quick movement by skillfully injecting a small amount of a complex cocktail containing potent venom peptides.…”