Gene transfer for targeted modification of salmonid fish metabolism

The reviewed studies addressed the possibility of using gene transfer for c orrection of L-ascorbic acid biosynthesis and carbohydrate utilization in r ainbow trout. Analyses of enzymatic activities in the L-AAB pathway indicat ed that reasons for the lack of L-AA production can be common in fish and s curvy-prone animals. Rat gulonolactone oxidase cDNA was transferred into tr out. Regardless of the fact that rGLO transcription occurred in embryos, ne ither GLO protein, nor enzyme activity were detected. There was no producti on of L-PLA in transgenic fish raised on vitamin C-free diets or injected w ith L-gulonolactone. These results indicated that the conditions required f or translation or stability of rGLO were not present in trout tissues. To a ugment carbohydrates utilization, human glucose transporter 1 and rat hexok inase II cDNAs were tested. In the transfected embryos, HK activity, rates of hexose uptake and glucose oxidation were increased. The effect of hGLUT1 on glucose metabolism was greater than that of rHKII. Trout carrying hGLUT 1 and rHKII with viral or piscine promoters were created. Though interpreta tion of the metabolic effects of the transgenes was complicated with mosaic ism, a tendency to improved carbohydrate utilization was revealed in some o f the transgenic individuals. (C) 1999 Elsevier Science B.V. All rights res erved.