Journal Article

Dramatic expansion of the black widow toxin arsenal uncovered by multi-tissue transcriptomics and venom proteomics

Garb, Jessica E, Haney, Robert A, Ayoub, Nadia A, Clarke, Thomas H, Hayashi, Cheryl Y

2014

Overview

Background Animal venoms attract enormous interest given their potential for pharmacological discovery and understanding the evolution of natural chemistries. Next-generation transcriptomics and proteomics provide unparalleled, but underexploited, capabilities for venom characterization. We combined multi-tissue RNA-Seq with mass spectrometry and bioinformatic analyses to determine venom gland specific transcripts and venom proteins from the Western black widow spider ( Latrodectus hesperus) and investigated their evolution. Results We estimated expression of 97,217  L. hesperus transcripts in venom glands relative to silk and cephalothorax tissues. We identified 695 venom gland specific transcripts (VSTs), many of which BLAST and GO term analyses indicate may function as toxins or their delivery agents. ~38% of VSTs had BLAST hits, including latrotoxins, inhibitor cystine knot toxins, CRISPs, hyaluronidases, chitinase, and proteases, and 59% of VSTs had predicted protein domains. Latrotoxins are venom toxins that cause massive neurotransmitter release from vertebrate or invertebrate neurons. We discovered ≥ 20 divergent latrotoxin paralogs expressed in L. hesperus venom glands, significantly increasing this biomedically important family. Mass spectrometry of L. hesperus venom identified 49 proteins from VSTs, 24 of which BLAST to toxins. Phylogenetic analyses showed venom gland specific gene family expansions and shifts in tissue expression. Conclusions Quantitative expression analyses comparing multiple tissues are necessary to identify venom gland specific transcripts. We present a black widow venom specific exome that uncovers a trove of diverse toxins and associated proteins, suggesting a dynamic evolutionary history. This justifies a reevaluation of the functional activities of black widow venom in light of its emerging complexity.

• Publisher: BioMed Central,BioMed Central Ltd
• Subject: Analysis / Animal Genetics and Genomics / Animals / Araneae / Arthropod Proteins - analysis / Biomedical and Life Sciences / Black Widow Spider - genetics / Black Widow Spider - metabolism / Genetic aspects / Genomics - methods / Latrodectus hesperus / Life Sciences / Mass Spectrometry - methods / Methods / Microarrays / Microbial Genetics and Genomics / Molecular Sequence Data / Multicellular invertebrate genomics / Phylogeny / Plant Genetics and Genomics / Proteome - analysis / Proteomics / Research Article / RNA sequencing / Sequence Analysis, RNA / Silk - genetics / Silk - metabolism / Spider Venoms - chemistry / Spider Venoms - genetics / Spider Venoms - metabolism / Transcriptome