Latrodectus tredecimguttatus, commonly known as black widow spider, is well known for its dangerous bite. Although its venom has been characterized extensively, some fundamental questions about its molecular composition remain unanswered. The limited transcriptome and genome data available prevent further understanding of spider venom at the molecular level. In the present study, we combined next-generation sequencing and conventional DNA sequencing to construct a venom gland transcriptome of the spider L. tredecimguttatus, which resulted in the identification of 9,666 and 480 high-confidence proteins among 34,334 de novo sequences and 1,024 cDNA sequences, respectively, by assembly, translation, filtering, quantification and annotation. Extensive functional analyses of these proteins indicated that mRNAs involved in RNA transport and spliceosome, protein translation, processing and transport were highly enriched in the venom gland, which is consistent with the specific function of venom glands, namely the production of toxins. Furthermore, we identified 146 toxin-like proteins forming 12 families, including 6 new families in this spider in which α-LTX-Lt1a family2 is firstly identified as a subfamily of α-LTX-Lt1a family. The toxins were classified according to their bioactivities into five categories that functioned in a coordinate way. Few ion channels were expressed in venom gland cells, suggesting a possible mechanism of protection from the attack of their own toxins. The present study provides a gland transcriptome profile and extends our understanding of the toxinome of spiders and coordination mechanism for toxin production in protein expression quantity.

No abstract

Black widow spider is one of the most poisonous spiders in the world. Up to now, there have been few systematic analyses of the spider venom components, and the mechanism of action of the venom has not been completely understood. In this work, we employed combinative proteomic strategy to analyze the venom collected from living adult spider Latrodectus tredecimguttatus by electrical stimulation. The experiments demonstrated that the venom is primarily composed of high molecular weight proteins and has high abundance proteins around 100 kDa. The content of peptides and proteins with low molecular weight is low. A total of 75 nonredundant venom proteins with distinct function were unambiguously identified. Besides the known black widow spider venom proteins including latrotoxins, a variety of hydrolases and other proteins with special activity were found in the venom, such as proteinase, phospholipase, phosphatase, nuclease, fucolectin, venom allergen antigen 5-like protein and trypsin inhibitor, and so on. Their possible biological actions and relationship with latrodectism were discussed. The results help to understand the complexity and action mechanism of L. tredecimguttatus venom.

Up to now, there have been a few reports on the toxic components purified from black widow spider (Latrodectus tredecimguttatus) eggs. In the present study, a novel neurotoxic protein was purified from the eggs by gel filtration combined with ion-exchange chromatography. Its molecular weight was 23.752 kDa determined by electrospray mass spectrometry. The protein could block the neuromuscular transmission in mouse-isolated phrenic nerve-hemidiaphragm preparations completely in a reversible manner and activate tetrodotoxin-sensitive sodium current in rat dorsal root ganglion cells. The N-terminal sequence of the protein was identified by the Edman degradation to be N-S-I-A-D-D-R-Y-R-W-P-G-Y-P-G-A-G-L-I-P-Y-I-I-D-S-. When the sequence was used to search against protein database with a sequence query in Mascot engine there was no matched sequence or protein whereas the Basic Local Alignment Search Tool (BLAST) analysis indicated that no significant similarity was found. These results demonstrated that the protein (named Latroeggtoxin-I) is a novel neurotoxic protein purified from the eggs of black widow spiders.

No abstract