Contribution of cysteamine dioxygenase to taurine biosynthesis in the oyster Crassostrea gigas

Shiqing Sun¹, Ning Kong², Wentong Hao¹, Keli Zhou¹, Junyan Zhao¹, Xiang Li¹, Lingling Wang¹, Linsheng Song³

Affiliations

¹ Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian 116023, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian 116023, China; Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian 116023, China.
² Dalian Jinshiwan Laboratory, Dalian 116034, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian 116023, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian 116023, China; Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian 116023, China. Electronic address: kongning@dlou.edu.cn.
³ Dalian Jinshiwan Laboratory, Dalian 116034, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian 116023, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao Marine Science and Technology Center, Qingdao, Shandong 266237, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian 116023, China; Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian 116023, China. Electronic address: lshsong@dlou.edu.cn.

PMID: 40602553
DOI: 10.1016/j.gene.2025.149650

Abstract

The Pacific oyster Crassostrea gigas is well-known for its exceptionally high taurine content, but the mechanisms underlying taurine biosynthesis remain largely unexplored. Thecysteamine (AET) pathway is one of the primary metabolic routes involved in taurine biosynthesis, and its role in mollusk taurine synthesis has garnered increasing recognition. In the present study, a cysteamine dioxygenase (ADO) homolog CgADO, the central enzyme of the AET pathway, was identified in C. gigas, which contained a typical PCO_ADO domain. The transcripts of CgADO were constitutively expressed in examined oyster tissues, with the highest level detected in the adductor muscle while the lowest in the hepatopancreas. The recombinant CgADO protein, expressed in Escherichia coli, was capable of converting cysteamine to hypotaurine. Overexpression of CgADO in HEK293T cells increased the production of taurine by 20.31-fold, compared to cells transfected with the empty vector. Inhibition of endogenous CgADO expression using RNA interference resulted in a 49% reduction in its mRNA expression and an 8% decline in taurine content in the adductor muscle of oysters. These results indicated that CgADO functioned as a cysteamine dioxygenase and played a certain role in taurine biosynthesis in C. gigas.

Keywords: Crassostrea gigas; Cysteamine dioxygenase; Cysteamine pathway; Taurine biosynthesis.

Gene. 2025 Sep 15:965:149650.doi: 10.1016/j.gene.2025.149650. Epub 2025 Jun 30.

Contribution of cysteamine dioxygenase to taurine biosynthesis in the oyster Crassostrea gigas

Abstract

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