Reduced Toxicity of Centruroides vittatus (Say, 1821) May Result from Lowered Sodium beta Toxin Gene Expression and Toxin Protein Production

Body tissue and venom glands from an eastern population of the scorpion Centruroides vittatus (Say, 1821) were homogenized and molecular constituents removed to characterize putative sodium beta toxin gene diversity, RT-qPCR, transcriptomic, and proteomic variation. We cloned sodium beta toxins from genomic DNA, conducted RT-qPCR experiments with seven sodium beta toxin variants, performed venom gland tissue RNA-seq, and isolated venom proteins for mass spectrophotometry. We identified >70 putative novel sodium beta toxin genes, 111 toxin gene transcripts, 24 different toxin proteins, and quantified sodium beta toxin gene expression variation among individuals and between sexes. Our analyses contribute to the growing evidence that venom toxicity among scorpion taxa and their populations may be associated with toxin gene diversity, specific toxin transcripts variation, and subsequent protein production. Here, slight transcript variation among toxin gene variants may contribute to the major toxin protein variation in individual scorpion venom composition.