Cloning and expression pattern of facilitative glucose transporter 1 (GLUT1) in gilthead sea bream Sparus aurata in response to salinity acclimation.

Facilitative glucose transporters (GLUT) are transmembrane transporter proteins involved in glucose transport across the plasma membrane. In fish, several GLUT mRNAs have been cloned, but to date there is no information about these transporters in the marine euryhaline teleost Sparus aurata. In the present study we obtained the complete coding sequence from S. aurata GLUT1 (saGLUT1), composed by 4483 bases, presenting a 79 to 95% identity with respect to other fish GLUT1 mRNAs. The analysis of the 5' and 3' UTRs showed the presence of several post-transcriptional regulatory elements. In addition, the effect on saGLUT1 mRNA expression of the osmotic acclimation to four different environmental salinities (5, 12, 40 and 55 ppt), in gills, kidney, liver and brain, was studied. Changes in mRNA expression levels were detected in gills and brain, indicating that GLUT1 has an important role in these organs for osmotic acclimation in S. aurata.