UTILIZATION OF GENOMICS FOR IMPROVING PRODUCTION TRAITS IN COOL AND COLD WATER AQUACULTURE
Location: Cool and Cold Water Aquaculture Research
Title: Molecular characterization of the Akt-TOR signaling pathway in rainbow trout: potential role in muscle growth/degradation
Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: October 19, 2010
Publication Date: January 15, 2011
Citation: Qi, N., Salem, M., Kenney, B., Leeds, T.D., Rexroad IIII, C.E., Yao, J. 2011. Molecular characterization of the Akt-TOR signaling pathway in rainbow trout: potential role in muscle growth/degradation. Plant and Animal Genome Conference. W042.
The Akt-TOR signaling pathway plays a key role in cellular metabolism and muscle growth. Hormone, nutrition and stress factors affect the Akt-TOR pathway by regulating gene transcription, protein synthesis and degradation. In addition, we previously showed that energetic demands elevate during vitellogenesis and egg maturation. In fish, little is known about the role of the Akt-TOR pathway in muscle growth and degradation.
Objectives: The objectives of this study were to: 1) Identify and characterize genes in the rainbow trout Akt-TOR signaling pathway; and 2) determine expression of Akt-TOR genes in association with starvation- and vitellogenesis-induced muscle atrophy as well as in association with the fish growth rate.
Results: We identified and characterized cDNA sequences of genes in the Akt-TOR signaling pathway, including extracellular signal-regulated kinases 1 and 2 (ERK1/2), ribosomal protein S6 kinase, polypeptide 3b (RSK), DNA-damage-inducible transcript 4 (REDD1), RAC serine/threonine-protein kinase (Akt), calcium binding protein 39 (MO25), Ras homolog enriched in brain (Rheb), G protein beta subunit-like (G beta L), TOR, translation initiation factor eIF-4B (Eif4B), small subunit ribosomal protein S6 (S6), translation initiation factor eIF-4E (Eif4e). Gene expression of the Akt-TOR signaling pathway was down-regulated in starvation- and vitellogenesis-induced muscle atrophy. On the contrary, the Akt gene showed elevated abundance in fish selected for fast growth. Further studies are underway to characterize the Akt-TOR pathway changes at post-transcriptional levels.
Conclusion: This study is the first high throughput analyses that characterize the Akt-TOR signaling pathway and address its role in muscle growth/degradation in a non-mammalian animal. The Akt-TOR genes will be evaluated as potential markers to facilitate selection for superior muscle growth and flesh quality in rainbow trout.