The role of Bcl-2 family genes in the physiology and immune response of the Pinctada fucata martensii

In the process of pearl production, Pinctada fucata martensii has a severe immune response, even leading to death. To effectively improve pearl production, researchers are committed to reducing immunological rejection through molecular biology methods. In previous studies, the apoptosis pathways were found to play an important function in the immune response of P. f. martensii. Bcl-2 family genes, the key genes in the apoptosis pathway, play a key role in regulating apoptotic pathways in cells. In the study, we cloned two genes of the P. f. martensii Bcl-2 family and named them respectively as PmBak/PmBcl-2. Fluorescence quantification of the pearl oysters' tissues showed that PmBak expression was highest in the hepatopancreas while PmBcl-2 expression was highest in the gill; nevertheless, different developmental stages showed that Bcl-2 family genes were highest in the blastula. Immune response assay using LPS, PGN, and poly I: C revealed that two genes were involved in the immune response; however, they showed relatively consistent expression patterns. To gain insight into the mechanism of action of the two genes, it was demonstrated by yeast two-hybrid experiments that PmBak and PmBcl-2 protein can interact with each other, while a subcellular localization assay revealed that Pmbak acts on mitochondria after apoptosis induction. In this study, we demonstrated the involvement of the Bcl-2 family of genes in the P. f. martensii immune response and explored the mechanism of the two genes. The study therefore provides insight into the mechanism of the apoptotic pathway in the immune response process of P. f. martensii.