Venom gland transcriptome from Heloderma horridum horridum by high-throughput sequencing

Lizards of the Helodermatidae (Anguimorpha) family consist of at least two well recognized species: Heloderma horridum horridum and Heloderma suspectum suspectum. They contain specialized glands in their jaws that produce venomous secretions that causes envenoming symptoms to bitten animals. One way to study proteins from such secretions is by RNA-seq; a powerful molecular tool to characterize the transcriptome of such specialized gland, and its protein secretions. The total RNA from venom gland tissues of H. horridum horridum was extracted and a cDNA library was constructed and sequenced. Overall, 114,172 transcripts were found, and 199 were annotated based on sequence similarities to previously described peptides/proteins. Transcripts coding for putative exendins, defensins, natriuretics and serine protease inhibitors were the most highly expressed. Transcripts that code for several putative serine proteases, phospholipases, metalloproteases, lipases, L-amino oxidase and nucleases were also found. Some of the novel identified transcripts were translationally controlled tumor proteins, venom factors, vespryns, waprins, lectins, cystatins and serine protease inhibitors. All these new protein structures may contribute to a better understanding of the venomous secretions of the Helodermatidae family. [Display omitted] •In the transcriptome of Heloderma horridum horridum identified one hundred ninety-nine annotated transcripts.•Thirty-two protein families were found in Hh. horridum venom gland with diverse putative functions.•Enzymes were the most abundant components of venom gland transcriptomic.•The annotated protein-coding transcripts have identities to snake (42%) and lizard (36%) venom components.•Transcripts coding putative exendins, defensins, natriuretics, and kazal inhibitor were the most highly expressed.