The cDNA sequence of the transferrin gene in tongue sole (Cynoglossus semilaevis) and its transcriptional changes under acute hypoxic stress

In this study, the cDNA sequence of the transferrin (Tf) gene in tongue sole (Cynoglossus semilaevis) (CsTf) was identified and characterised. The full length of CsTf cDNA was 2281 bp encoding 677 amino acids (aa). The mature CsTf protein was found to be made up of 656 aa and it consisted of two lobes (N- and C-lobes). Two- and three- dimensional (2-D and 3-D) structure analysis showed that CsTf possesses a similar structure (multi-α helix/β-sheet) to human Tf. Real-time polymerase chain reaction (PCR) analysis showed that CsTf was mainly expressed in the liver, and moderately expressed in the heart, spleen and kidney. Moreover, CsTf was up-regulated in different tissues under acute hypoxia [dissolved oxygen (DO)=0.8 mg/L]. Our results suggest that CsTf plays a role in fish’s adaptation to hypoxic stress.