Towards Understanding PRPS1 as a Molecular Player in Immune Response in Yellow Drum ().

Phosphoribosyl pyrophosphate synthetases (EC 2.7.6.1) are key enzymes in the biological synthesis of phosphoribosyl pyrophosphate and are involved in diverse developmental processes. In our previous study, the gene was discovered as a key disease-resistance candidate gene in yellow drum, , in response to the infection of , through genome-wide association analysis. This study mainly focused on the characteristics and its roles in immune responses of the gene in yellow drum. In the present study, the gene was cloned from yellow drum, encoding a protein of 320 amino acids. Bioinformatic analysis showed that PRPS1 was highly conserved during evolution. Quantitative RT-PCR demonstrated that was highly expressed in the head-kidney and brain, and its transcription and translation were significantly activated by infection examined by RT-qPCR and immunohistochemistry analysis, respectively. Subcellular localization revealed that PRPS1 was localized in cytoplasm. In addition, semi-in vivo pull-down assay coupled with mass spectrometry identified myeloid differentiation factor 88 (MyD88) as an PRPS1-interacting patterner, and their interaction was further supported by reciprocal pull-down assay and co-immunoprecipitation. The inducible expression of by suggested that the linker molecule MyD88 in innate immune response may play together with PRPS1 to coordinate the immune signaling in yellow drum in response to the pathogenic infection. We provide new insights into important functions of PRPS1, especially PRPS1 in the innate immunity of teleost fishes, which will benefit the development of marine fish aquaculture.