In-Depth Venome of the Brazilian Rattlesnake Crotalus durissus terrificus: An Integrative Approach Combining Its Venom Gland Transcriptome and Venom Proteome

Snake venoms are complex mixtures mainly composed of proteins and small peptides. Crotoxin is one of the most studied components from Crotalus venoms, but many other components are less known due to their low abundance. The venome of Crotalus durissus terrificus, the most lethal Brazilian snake, was investigated by combining its venom gland transcriptome and proteome to create a holistic database of venom compounds unraveling novel toxins. We constructed a cDNA library from C. d. terrificus venom gland using the Illumina platform and investigated its venom proteome through high resolution liquid chromotography–tandem mass spectrometry. After integrating data from both data sets, more than 30 venom components classes were identified by the transcriptomic analysis and 15 of them were detected in the venom proteome. However, few of them (PLA2, SVMP, SVSP, and VEGF) were relatively abundant. Furthermore, only seven expressed transcripts contributed to ∼82% and ∼73% of the abundance in the transcriptome and proteome, respectively. Additionally, novel venom proteins are reported, and we highlight the importance of using different databases to perform the data integration and discuss the structure of the venom components-related transcripts identified. Concluding, this research paves the way for novel investigations and discovery of future pharmacological agents or targets in the antivenom therapy.

蛇毒是一类以蛋白质与小分子肽为核心组分的复杂混合体系。克罗毒素（Crotoxin）是研究最为深入的响尾蛇（Crotalus）毒液组分之一，但由于多数组分丰度较低，其相关研究仍较为匮乏。本研究针对巴西致死性最强的蛇类——南美响尾蛇（Crotalus durissus terrificus）的毒液组开展研究，通过整合其毒腺转录组（transcriptome）与毒液蛋白质组（proteome）数据，构建了覆盖毒液全部组分的完整数据库以挖掘新型毒素。本研究依托Illumina测序平台构建了南美响尾蛇毒腺的cDNA文库，并通过高分辨液相色谱-串联质谱技术对其毒液蛋白质组进行分析。整合两组学数据后，转录组分析共鉴定出30余种毒液组分类别，其中15类可在毒液蛋白质组中被检测到。然而其中仅少数组分（磷脂酶A2（Phospholipase A2, PLA2）、蛇毒金属蛋白酶（Snake Venom Metalloproteinase, SVMP）、蛇毒丝氨酸蛋白酶（Snake Venom Serine Protease, SVSP）以及血管内皮生长因子（Vascular Endothelial Growth Factor, VEGF））呈现出较高的丰度。此外，仅7个表达的转录本分别贡献了转录组与蛋白质组中约82%和73%的总丰度。本研究还报道了新型毒液蛋白，强调了采用多数据库开展数据整合的重要性，并对所鉴定的毒液组分相关转录本的结构进行了探讨。综上，本研究为后续相关研究以及抗蛇毒疗法中新型药理学靶点或药物的发现奠定了坚实基础。