Phospholipase A2 genes and their expressions in Thai Russell's viper venom glands.

Phospholipase A2 (PLA2) is a multi-functional enzyme found in many snake venoms and exists in several isoforms. PLA2 causes a variety of pathological effects including anticoagulant, edema, and platelet aggregation inhibition. Here, we reported the cDNA and gene sequences of PLA2 and their expressions in Thai Russell's viper (RV) Daboia russellii siamensis venom glands. We identified 3 PLA2 genes in the RV genome, 2 of which are actively transcribed in the venom gland. The deduced amino acids of these 2 PLA2 isoforms share 80% identity and are the same as PLA2s from Taiwan Russell's viper, Daboia russellii formosensis. A third PLA2 gene has no corresponding mRNA transcript from the venom gland suggesting a very low level of expression in the venom glands.