Venom Diversity and Evolution in the Most Divergent Cone Snail Genus Profundiconus

Giulia Fassio,Mandё Holford,Yuri I Kantor,Maria Vittoria Modica,Paul Zaharias,Nicolas Puillandre,Juliette Gorson,Lou Mary,Alexander E Fedosov

doi:10.3390/toxins11110623

Abstract

Profundiconus is the most divergent cone snail genus and its unique phylogenetic position, sister to the rest of the family Conidae, makes it a key taxon for examining venom evolution and diversity. Venom gland and foot transcriptomes of Profundiconus cf. vaubani and Profundiconus neocaledonicus were de novo assembled, annotated, and analyzed for differential expression. One hundred and thirty-seven venom components were identified from P. cf. vaubani and 82 from P. neocaledonicus, with only four shared by both species. The majority of the transcript diversity was composed of putative peptides, including conotoxins, profunditoxins, turripeptides, insulin, and prohormone-4. However, there were also a significant percentage of other putative venom components such as chymotrypsin and L-rhamnose-binding lectin. The large majority of conotoxins appeared to be from new gene superfamilies, three of which are highly different from previously reported venom peptide toxins. Their low conotoxin diversity and the type of insulin found suggested that these species, for which no ecological information are available, have a worm or molluscan diet associated with a narrow dietary breadth. Our results indicate that Profundiconus venom is highly distinct from that of other cone snails, and therefore important for examining venom evolution in the Conidae family.

Highlights

As stated by the “father” of toxicology, “Omnia venenum sunt: nec sine veneno quicquam existit.Dosis sola facit, ut venenum non fit.”: Everything can be a venom, only the dose makes the differenceToxins 2019, 11, 623; doi:10.3390/toxins11110623 www.mdpi.com/journal/toxinsToxins 2019, 11, 623 between a poisoning and a non-poisoning substance [1]
By similarity with other venom components and by subcellular localization, and removing duplicates, 223 unique putative venom components were retrieved, including those enriched in the venom gland (VG), all considered new because having ≥1 amino acid of difference from previously published sequences
137 unique venom components were retrieved from P. cf. vaubani, 82 from P. neocaledonicus, and 4 were shared by both

Summary

Introduction

Toxins 2019, 11, 623 between a poisoning and a non-poisoning substance [1] This intuition deftly summarized what happened independently several times across the animal kingdom, where gene families, encoding for proteins normally involved in key regulatory processes, were recruited for venom production [2]. Venom is a complex mixture of different components generally referred to as ‘toxins’, which directly interfere with the physiology of the prey acting often as neurotoxins or enzymes impairing haemostasis [2,3] They can be listed as venom components those enzymes involved in post-translational modifications, folding processes, and in enhancing venom activity by easing toxins spreading [2,3]

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Conclusion