OsHV-1 Promoter-driven Transgene Expression in Bivalve Cells: An In Vitro Study with an EGFP-tagged Oncogenic H-RasV12.

Bivalves, being extractive species, support sustainable aquaculture and the principles of a circular bioeconomy. Biotechnological interventions can improve bivalve aquaculture productivity. For example, transgene expression facilitates gene function analysis which enables the identification of desirable traits in bivalves for aquaculture. Transgene expression also finds applications in the development of bivalve cell lines that, in turn, support pathology research, eco-toxicology and aquaculture environment quality assessment, and advancing cultivated seafood technology (aligned with sustainability goals). In this study, the efficacy of a synthesized OsHV-1 (ostreid herpesvirus 1) promoter in driving transgene expression across diverse cell culture systems was tested, including primary cell cultures from the bivalve Magallana bilineata. The expression of the oncogenic H-RasV12, tagged with an enhanced green fluorescent protein (EGFP), under the control of the OsHV-1 promoter was also analyzed. The results showed that the OsHV-1 promoter exhibited better activity than the widely used CMV (cytomegalovirus) promoter, highlighting the potential of synthesized promoters for transgene expression in molluscan cells. Furthermore, the study suggests that optimizing gene delivery methods and incorporating multiple oncogenes could enhance molluscan cell transformation, paving the way for developing bivalve cell lines as valuable tools in aquatic biotechnology.