Biomineralization mechanism and evolution of nano-structured habu snake venom fang

有毒动物不仅有产毒腺，而且还有注射毒液的器官，如携带毒液的尖牙和线虫囊，以有效地向猎物物种注射毒液。虽然人们认为毒牙是从牙齿功能进化而来的，但其生物矿化机制尚不清楚。本研究采用蛋白质组学和转录组学相结合的方法，对黄绿色原虫蛇毒毒牙基质蛋白的结构和性质进行了分析。2D-PAGE显示20多个蛋白质斑点，等电点在4~5之间，相对分子质量在25~55 kDa之间，主要成分为I型胶原。此外，通过对牙齿形成组织的RNA-SEQ分析，从转录产物中鉴定出与生物矿化相关的蛋白，如骨调节蛋白、IMPG2、牙本质基质蛋白1等。

Venomous animals have not only the venom-producing gland but also venome-injecting organs such as venom-loaded fangs and nematocyst for the efficient venome-injection to prey species. Although it is considered that the venom fang have evolved functionally from teeth, their biomineralization mechanisms are still unknown.In this study, to clarify the structure and properties of the matrix proteins from Protobothrops flavoviridis (habu) snake venom fangs were analysed by combined proteomic and transcriptomics analyses.Venom-loaded fangs were calcified with 50% formic acid, and their proteins were extracted by 8M urea. 2D-PAGE showed the more than 20 protein spots with the isoelectric point ranging 4 to 5 and molecular weight of 25-55kDa including type I collagen as a major component. Furthermore, the biomineralization related proteins such as osteomodulin, IMPG2, dentin matrix protein 1 etc. were identified from transcription products by RNA-seq analysis of fang-forming tissues.