A catalog for transcripts in the venom gland of the Agkistrodon acutus: Identification of the toxins potentially involved in coagulopathy

Agkistrodon acutus is a special agkistrodon halys, only distributed in Southern China, with a few exceptions in Vietnam. It is a cherished element used in traditional Chinese medicine. In order to produce a global panorama of gene expression in the Agkistrodon acutus venom gland, a non-normalized cDNA library was constructed, and 8696 high quality 5′ end expressed sequenced tags (ESTs) were sequenced and analyzed. The initial sequences were assembled into 2855 clusters. Of these clusters, only 45.60% clusters matched known sequence and 54.40% had no match to any known sequence in GenBank. Except for putative cellular proteins (1184 clusters), the remaining 118 clusters (40.16% of all ESTs) corresponded to sequences associated with diverse toxin function. According to expression abundance, the major toxin components were metalloproteinases (32.08%) and C-type lectin (5.22%), and other components including bradykinin-potentiating peptide (0.90%), serine proteases (0.51%), nucleotidase and nuclease (0.41%), phospholipase A2 (0.30%), disintegrin (0.05%), cytokine-like molecules (0.06%), and other proteins (0.63%). The majority of these components are thought to be responsible for coagulopathy after A. acutus bites. We have therefore generated a comprehensive catalog of the A. acutus venom gland described so far. Gene expression from the very specialized secretory tissue, especially for those involved in coagulopathy, can be surveyed and provide important information in finding novel toxins.