title: Analysis of expressed sequence tags from the venom ducts of Conus striatus: focusing on the expression profile of conotoxins.
abstract: Cone snails (genus Conus) are predatory marine gastropods that use venom peptides for interacting with prey, predators and competitors. A majority of these peptides, generally known as conotoxins demonstrate striking selectivity in targeting specific subtypes of ion channels and neurotransmitter receptors. So they are not only useful tools in neuroscience to characterize receptors and receptor subtypes, but offer great potential in new drug research and development as well. Here, a cDNA library from the venom ducts of a fish-hunting cone snail species, Conus striatus is described for the generation of expressed sequence tags (ESTs). A total of 429 ESTs were grouped into 137 clusters or singletons. Among these sequences, 221 were toxin sequences, accounting for 52.1% (corresponding to 19 clusters) of all transcripts. A-superfamily (132 ESTs) and O-superfamily conotoxins (80 ESTs) constitute the predominant toxin components. Some non-disulfide-rich Conus peptides were also found. The expression profile of conotoxins also explained to some extent the pharmacological and physiological reactions elicited by this typical piscivorous species. For the first time, a nonstop transcript of conotoxin was identified, which is suggestive that alternative polyadenylation may be a means of post-transcriptional regulation of conotoxin production. A comparison analysis of these conotoxins reveals the different variation and divergence patterns in these two superfamilies. Our investigations indicate that focal hyper-mutation, block substitution and exon shuffling are three main mechanisms leading to the conotoxin diversity in a species. The comprehensive set of Conus gene sequences allowed the identification of the representative classes of conotoxins and related components, which may lay the foundation for further research and development of conotoxins.
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Therapeutic Functional Genes, Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, 135 Xingangxi Road, 510275 Guangzhou, China.
authors.forename: Canhui
authors.initials: C
authors.lastname: Pi
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.forename: Can
authors.initials: C
authors.lastname: Peng
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Jiang
authors.forename: Junliang
authors.initials: J
authors.lastname: Liu
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.forename: Xuesong
authors.initials: X
authors.lastname: Yu
authors.forename: Yanghong
authors.initials: Y
authors.lastname: Yu
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Jiang
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Meiling
authors.initials: M
authors.lastname: Dong
authors.forename: Shangwu
authors.initials: S
authors.lastname: Chen
authors.forename: An-Long
authors.initials: AL
authors.lastname: Xu
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D020916:Conotoxins / Q000145:classification / Q000235:genetics*; D052078:Conus Snail / Q000033:anatomy & histology / Q000737:chemistry / Q000235:genetics; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D015723:Gene Library; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment
chemical_list: D020916:Conotoxins