Rapid Identification of Phospholipase A2 Transcripts from Snake Venoms

Phospholipase A2 (PLA2) is a major component in snake venoms and it is found in many different isoforms. To identify transcripts encoding different PLA2 isoforms, we developed a simple, rapid procedure. Total RNA was extracted from the venoms of three cottonmouth snakes and two diamondback rattlesnakes, and further reverse-transcribed into complementary DNA (cDNA). Using one pair of cottonmouth PLA2-specific primers and Reverse Transcription Polymerase Chain Reaction (RT-PCR) technique, we identified 27 unique full-length PLA2 transcripts, including nine sequences identical to the previously documented ones in the database and one novel GIII-like PLA2. Two common transcripts respectively encoding Asp49 and Lys49 PLA2 isoforms were identified in all three cottonmouth venoms that contain more PLA2 transcripts than diamondback rattlesnake venoms. The placement of cloned PLA2 transcripts in snake venom PLA2s was further discussed by phylogenetic analysis. The procedure developed in this study paves the way for accelerated acquisition of transcriptome data on any other venom toxin families. The results obtained are crucial for insight into the structure and function of PLA2 isoforms for scientific and potential therapeutic purposes