Exon Shuffling and Origin of Scorpion Venom Biodiversity

• Published in: Toxins 2017-01, Vol.9 (1), p.10-10
• Main Authors: Wang, Xueli, Gao, Bin, Zhu, Shunyi
• Format: Article
• Language: English
• Subjects: Animals; Antimicrobial peptides; Biodiversity; Combinatorial analysis; exon shuffling; exon-intron structure; Exons; Gene Library; Gene sequencing; Genes; Introns; Ion channels; Libraries; molecular diversity; Neural coding; Neurotoxins; Neurotoxins - chemistry; Neurotoxins - genetics; Nucleotide sequence; Nucleotides; Peptides; Peptides - chemistry; Protease inhibitors; Protein arrays; Protein Conformation; Proteinase inhibitors; Proteins; Proteomics; Pyridine nucleotide reductase; Recombination, Genetic; Recruitment; Regulatory sequences; scorpion venom; Scorpion Venoms - chemistry; Scorpion Venoms - genetics; Scorpions; Toxins; Transcriptome; Venom; Venom gland
• ISSN: 2072-6651; 2072-6651
• DOI: 10.3390/toxins9010010

Scorpion venom is a complex combinatorial library of peptides and proteins with multiple biological functions. A combination of transcriptomic and proteomic techniques has revealed its enormous molecular diversity, as identified by the presence of a large number of ion channel-targeted neurotoxins with different folds, membrane-active antimicrobial peptides, proteases, and protease inhibitors. Although the biodiversity of scorpion venom has long been known, how it arises remains unsolved. In this work, we analyzed the exon-intron structures of an array of scorpion venom protein-encoding genes and unexpectedly found that nearly all of these genes possess a phase-1 intron (one intron located between the first and second nucleotides of a codon) near the cleavage site of a signal sequence despite their mature peptides remarkably differ. This observation matches a theory of exon shuffling in the origin of new genes and suggests that recruitment of different folds into scorpion venom might be achieved via shuffling between body protein-coding genes and ancestral venom gland-specific genes that presumably contributed tissue-specific regulatory elements and secretory signal sequences.