A Combined Transcriptomics and Proteomics Approach Reveals the Differences in the Predatory and Defensive Venoms of the Molluscivorous Cone Snail Cylinder ammiralis (Caenogastropoda: Conidae)

Abstract

Venoms are complex mixtures of proteins that have evolved repeatedly in the animal kingdom. Cone snail venoms represent one of the best studied venom systems. In nature, this venom can be dynamically adjusted depending on its final purpose, whether to deter predators or hunt prey. Here, the transcriptome of the venom gland and the proteomes of the predation-evoked and defensive venoms of the molluscivorous cone snail Cylinder ammiralis were catalogued. A total of 242 venom-related transcripts were annotated. The conotoxin superfamilies presenting more different peptides were O1, O2, T, and M, which also showed high expression levels (except T). The three precursors of the J superfamily were also highly expressed. The predation-evoked and defensive venoms showed a markedly distinct profile. A total of 217 different peptides were identified, with half of them being unique to one venom. A total of 59 peptides ascribed to 23 different protein families were found to be exclusive to the predatory venom, including the cono-insulin, which was, for the first time, identified in an injected venom. A total of 43 peptides from 20 protein families were exclusive to the defensive venom. Finally, comparisons of the relative abundance (in terms of number of peptides) of the different conotoxin precursor superfamilies showed that most of them present similar abundance regardless of the diet.

Venom system variation and the division of labor in the colonial hydrozoan Hydractinia symbiolongicarpus

“…venom metering; Morgenstern and King, 2013 ). Several phylogenetically-distant species have managed this tradeoff in such a way to simultaneously produce, maintain, and in some cases independently inject venom cocktails specific to the ecological context, including predatory and defensive venoms in cone snails ( Dutertre et al, 2014 ; Abalde et al, 2021 ) and the assassin bug Pristhesancus plagipennis ( Walker et al, 2018 ). Various strategies for modulating venom output appear to have emerged across the tree of life ( Schendel et al, 2019 ).…”

Comparative Venomics of the Cryptic Cone Snail Species Virroconus ebraeus and Virroconus judaeus

“…Conotoxins are produced as precursors, which include an Nterminal signal that targets the peptide at the endoplasmic reticulum, a propeptide region, which helps in the processing and folding of the peptide [3], and a mature domain, which is a relatively short peptide that establishes disulfide bonds between cysteine residues to set up the native structure of the toxin. In recent years, hormones (e.g., insulin), other peptides, and small molecules have been detected in the venom ducts, and are proposed to play an active role in the envenomation process [4][5][6]. Each time that a cone snail propels its hollow radular tooth into its prey or a predator, the venom is injected and hundreds of different peptides start blocking ion channels, as well as neurotransporters and hormone receptors.…”

DeTox: a pipeline for the detection of toxins in venomous organisms

“…Our results highlight DeTox as a valuable tool to detect novel putative toxins. However, it is always necessary to verify their actual function by confirming the presence of matching proteins in the proteomes of the venom gland or the injected venom [ 55 ], and by performing in vitro / in vivo experiments to identify the molecular target and the exact function of the toxin [ 8 , 56 , 57 ].…”