Abstract: This study aimed at exploring the molecular characteristics of GNPTAB（alpha / beta subunits of N-acetylglucosamine- 1-phosphotransferase）gene and its immune response to infection with Aeromonas veronii in koi carp Cyprinus carpio var. koi. The CDS region of GNPTAB gene in koi carp was analyzed by bioinformatics. Real-time fluorescence quantitative PCR technology was applied to investigate the tissue distribution of GNPTAB gene from healthy C. carpio var. koi and its temporal expression in different tissues of the fish following challenging with A.veronii. The results showed that the length of GNPTAB gene CDS fragment was 3 747 bp, which encoded 1 248 amino acid and contained four specific domains. Real-time fluorescence Quantitative PCR analysis showed that GNPTAB was expressed in all tested tissues of healthy C. carpio var. koi, with the highest expression in the liver, followed by the muscle, intestine, spleen, skin, midkidney and head kidney. During 6-72 h after experimental infection with A. veronii in the C. carpio var. koi, the expression of GNPTAB was up-regulated in the intestine, while down-regulated in the liver, head kidney, spleen, skin and muscle. The differentiated expression in the tested tissues following infection with A. veronii in the C. carpio var. koi suggested that GNPTAB was involved in the pathophysiological process or the immune response against A. veronii.

Key words: Cyprinus carpio var. koi, bioinformatics analysis, tissue distribution, temporal expression, GNPTAB