Venom-gland transcriptomics of the Malayan pit viper (Calloselasma rhodostoma) for identification, classification, and characterization of venom proteins

Poom Adisakwattana; Lawan Chanhome; Narongsak Chaiyabutr; Orawan Phuphisut; Reamtong Onrapak; Charin Thawornkuno

doi:10.1016/j.heliyon.2023.e15476

Venom-gland transcriptomics of the Malayan pit viper (Calloselasma rhodostoma) for identification, classification, and characterization of venom proteins

Heliyon. 2023 Apr 19;9(5):e15476. doi: 10.1016/j.heliyon.2023.e15476. eCollection 2023 May.

Authors

Poom Adisakwattana¹, Lawan Chanhome², Narongsak Chaiyabutr², Orawan Phuphisut¹, Reamtong Onrapak³, Charin Thawornkuno³

Affiliations

¹ Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.
² Queen Saovabha Memorial Institute, Thai Red Cross Society, Bangkok, 10330, Thailand.
³ Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.

Abstract

The Malayan pit viper (Calloselasma rhodostoma) is a hemotoxic snake widely found in Southeast Asia and is responsible for the majority of poisoning cases in this region, including Thailand. However, a comprehensive knowledge of the venom protein profile and classification, as well as novel venom proteins, of this viper is still limited. Recently, the detailed composition of several snake venoms has been discovered through the use of transcriptome analysis. Therefore, the aim of this study was to employ a next-generation sequencing platform and bioinformatics analysis to undertake venom-gland de novo transcriptomics of Malayan pit vipers. Furthermore, 21,272 functional coding genes were identified from 36,577 transcripts, of which 314 transcripts were identified as toxin proteins, accounting for 61.41% of total FPKM, which can be categorized into 22 toxin gene families. The most abundant are snake venom metalloproteinase kistomin (P0CB14) and zinc metalloproteinase/disintegrin (P30403), which account for 60.47% of total toxin FPKM and belong to the SVMP toxin family, followed by snake venom serine protease 1 (O13059) and Snaclec rhodocetin subunit beta (P81398), which account for 6.84% and 5.50% of total toxin FPKM and belong to the snake venom serine protease (SVSP) and Snaclec toxin family, respectively. Amino acid sequences of the aforementioned toxins were compared with those identified in other important medical hemotoxic snakes from Southeast Asia, including the Siamese Russell's viper (Daboia siamensis) and green pit viper (Trimeresurus albolabris), in order to analyze their protein homology. The results demonstrated that ranges of 58%-62%, 31%-60%, and 48%-59% identity was observed among the SVMP, Snaclec, and SVSP toxin families, respectively. Understanding the venom protein profile and classification is essential in interpreting clinical symptoms during human envenomation and developing potential therapeutic applications. Moreover, the variability of toxin families and amino acid sequences among related hemotoxic snakes found in this study suggests the use and development of universal antivenom for the treatment of envenomating patients is still challenging.

Keywords: Calloselasma rhodostoma; Hemotoxic venom; Trancriptomics; Venom-gland; Venomous snakes.