Molecular cloning, characterization, tissue expression and nutritional regulation of O‐Glc NA c transferase gene in hybrid grouper ( Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂ )

O‐Glc NA c transferase gene ( OGT ) was considered as the sole rate‐limiting enzyme in the O‐Glc NA c modification. In the present study, the OGT gene of hybrid grouper ( Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) was cloned and characterized, and its expression in response to dietary carbohydrate level and acute glucose treatment was investigated. The full‐length of OGT (GenBank accession no. KY656469 ) was 4,063 bp, including a 302 bp 5′untranslated terminal region ( UTR ), a 3,165 bp coding region that encoded 1,054 amino acids residues and a 596 bp 3′ UTR . The highly conservation of OGT gene between fish and mammals was also observed through multiple sequences alignment and phylogenetic analysis. O‐Glc NA c transferase gene was ubiquitously expressed in all detected tissues with highest expressions in brain and liver, to a lesser degree, in eye, heart, kidney and intestine. The increasing dietary carbohydrate from 8.02% to 16.08% had no significant effect on the mRNA expression of OGT . However, the expression of OGT was slightly elevated at 6 hr post‐glucose injection, and the elevation became significant at 24 hr time‐point. These data may enhance our understanding on the nutritional regulation of OGT and O‐Glc NA c modification in fish species.