title: Exon Shuffling and Origin of Scorpion Venom Biodiversity.
abstract: 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.
authors.affiliation: Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China. wangxueli@ioz.ac.cn.
authors.forename: Xueli
authors.initials: X
authors.lastname: Wang
authors.affiliation: Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China. gaob@ioz.ac.cn.
authors.forename: Bin
authors.initials: B
authors.lastname: Gao
authors.affiliation: Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China. zhusy@ioz.ac.cn.
authors.forename: Shunyi
authors.initials: S
authors.lastname: Zhu
mesh_terms: D000818:Animals; D005091:Exons; D015723:Gene Library; D007438:Introns; D009498:Neurotoxins / Q000737:chemistry* / Q000235:genetics; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation; D040901:Proteomics; D011995:Recombination, Genetic; D012604:Scorpion Venoms / Q000737:chemistry* / Q000235:genetics; D012605:Scorpions; D059467:Transcriptome
chemical_list: D009498:Neurotoxins; D010455:Peptides; D012604:Scorpion Venoms
keywords: exon shuffling; exon-intron structure; molecular diversity; scorpion venom