Expression of Human Glucose Transporter Type 1 and Rat Hexokinase Type II Complementary DNAs in Rainbow Trout Embryos: Effects on Glucose Metabolism.
: Sugars are utilized poorly in fish mainly because of low rates of transport across plasma membrane and phosphorylation. To evaluate whether it is possible to augment carbohydrate metabolism in fish using heterologous genes, expression of human glucose transporter type 1 (hGLUT1) and rat hexokinase type II (rHKII) complementary DNAs cloned with cytomegalovirus promoter was followed in rainbow trout embryos. Both genes were transcribed. Hexokinase activity, undetectable in control, was found in transformed blastulas. Increased rates of 14C-methylglucose uptake and sensitivity to cytochalasin B indicated the presence of facilitative hexose transport due to hGLUT1 expression. Effect of hGLUT1 on production of 14CO2 from glucose was greater than that of rHKII. Coexpression of the genes did not increase the rate of glucose oxidation compared with expression of hGLUT1 alone.
Krasnov
A
Institute of Applied Biotechnology, University of Kuopio, P.O. Box 1627, 70211 Kuopio, Finland
Pitkänen
TI
Reinisalo
M
Mölsä
H