cDNA, Genome Cloning, and mRNA Expression of Phospholipase A2 Gene from the Rhopilema Esculentum

Abstract:

The cDNA and gene of phospholipase A2 (Re-PLA2-1) of Rhopilema esculentum were cloned using RACE, and the mRNA expression was monitored at different developmental stages with quantitative real-time PCR analysis. The full-length cDNA of Re-PLA2-1 was 824 bp, containing a 5’-untranslated region (5’-UTR) of 48 bp, an open reading frame (ORF) of 504 bp, and a 3’- untranslated region (3’-UTR) of 272 bp. SMART analysis showed that Re-PLA2-1 was a secreted protein, including a putative signal peptide consisting of 19 amino acid residues and a domain of phospholipase A2. The deduced amino acid sequence of Re-PLA2-1 was highly similar to those of PLA2s from Conus magus, Nematostella vectensis, Crassostrea gigas and so on, and they could form a cluster of pfam09056 GⅨ PLA2 revealed by the multiple sequence alignment and phylogenetic analysis. They shared the essential features of pfam09056 PLA2s family, including a calcium-binding site, the catalytic active sites, and a PLA2 domain, which perfectly corresponds to the conserved disulfide-bonded cysteine residues involved in the formation of the internal disulfide. The size of Re-PLA2-1 gene was 2671 bp that included four exons and three introns. Quantitative real-time PCR analysis revealed that the expression of Re-PLA2-1 mRNA occurred in all four developmental stages. The expression was the highest in strobila and the lowest in ephyra. These results contributed to further understanding the biological function of PLA2 in R. esculentum.