Transcriptome Analysis Of The Venom Gland Of The Fishing Spider Dolomedes Sulfurous

Dolomedes sulfurous and Dolomedes mizhoanus,located in Guangxi province of china,are two fish-hunting spiders feeding on small fish and belong to genus Dolomedes,family Pisauridae.Our laboratory has researched their venoms in biochemical and electrophysiological properties.It is found that they potentially inhibit voltage-activated Na⁺,K⁺and Ca²⁺channels in rat dorsal root ganglion neurons.The transcriptomic information of the venom gland cDNA library of D.mizhoanus has been illustrated in our previous study.In this work,we get the transcriptomic information of the venom gland cDNA library of D.sulfurous.Based on it we perform a comparative analysis of the venoms from the two spiders to investigate the evolutionary relationship.Due to the limited crude venoms collected from the two spiders,it can not satisfy the needs of research.The cDNA library is the regular method for functional genomics.In this work,we first performed a transcriptomic analysis by constructing the venom gland cDNA library of D.sulfurous.As a result,267 high-quality expressed sequence tags?ESTs?were generated.Of the 267 ESTs,71%?190 of 267 ESTs?encoded toxin-like precursors,24%?65 of 267 ESTs?encoded cellular transcripts and 5%?12 of 267 ESTs?had no significant similarity to any known sequences.After removing the redundant sequences,127 novel toxin-like sequences were identified,which were classified into seven supfamilies based on the sequences similarity and disulfide bond arrangement.A comparison between the two spider toxin-like sequences,conserved cysteine patterns and structural domains was performed,which revealed that they shared high sequence similarity and the toxins from both spiders contained 6-12cysteine residues forming seven cysteine patterns.Blast search and domain architectures prediction indicated that the two venoms were rich of neurotoxins targeting ion channels with pharmacological and therapeutic significances.It was suggested that the toxins from both spiders were closed in the relationship,although different toxins were found to be evolved independently in the two spider venoms during evolution.The result should provide clues for researching the biodiversity and evolution of spider toxins.We also annotated the eukaryotic orthologous group?KOG?of the genes encoded body proteins in the cDNA library.This study highlights the evolutionary relationship of the toxins from the two spiders and provides reliable basis for structure and function investigation of individual toxins in the future.