Submitted to: Fish Physiology and Biochemistry Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2006
Publication Date: 9/13/2006
Citation: Coulibaly, I., Gahr, S.A., Yao, J., Rexroad III, C.E. 2006. Embryonic expression of uncoupling protein 2 genes in rainbow trout. Fish Physiology and Biochemistry Journal. 32:249-253. Interpretive Summary: The identification of genes affecting aquaculture production traits can lead to increased understanding of the mechanisms underlying physiological processes and result in molecular based tests that will facilitate the genetic improvement of broodstock. The uncoupling protein 2 (UCP2) gene has been described to play a role in various physiological processes in mammals such as energy partitioning, body weight control, fatty acid metabolism and control of reactive oxygen species. In a previous report we characterized two copies of UCP2 (UCP2A and UCP2B) in the rainbow trout genome. The present study was designed to analyze the changes in UCP2A and UCP2B mRNA expression throughout rainbow trout embryonic and larval development. We observed that UCP2A and UCP2B were highly expressed early during embryonic development, showing similar patterns from fertilization to hatching and appearing differentiated in successive stages. We hypothesize that UCP2A and UCP2B expression in the rainbow trout developing embryo and alevin could be associated with the utilization of fatty acids as sources of energy for growth and development, therefore having the potential to impact important economic traits in adult fish.
Technical Abstract: Uncoupling proteins are mitochondrial anion transporters that dissociate respiration from ATP synthesis through proton leaks. Uncoupling protein 2 reportedly plays a role in several physiological processes such as energy partitioning, nutrition and fatty acid metabolism. The mRNA expression of rainbow trout UCP2s (UCP2A and UCP2B) was monitored during embryogenesis and early larval development. Both genes were recruited early and displayed similar steady decreasing patterns from fertilization until hatching. UCP2A and UCP2B expression appeared significantly differentiated after hatching and during the yolk sac absorption, with UCP2A displaying higher expression. We suggest that UCP2 expression profiles in the rainbow trout embryo could be associated with the utilization of lipids as sources of energy during development.