Hepatic gene expression profiling of GH transgenic coho salmon with and without ration restriction

This is the first use of cDNA microarrays to study the influence of GH transgenesis on liver gene expression in a non-mammalian vertebrate. Three groups of salmon were examined: transgenic on full ration (T), transgenic on restricted ration (R), and control nontransgenic (C). Daily weight gains in T were approximately 8-fold higher than in C, and 4-fold higher than in R. Differential gene expression in T, R, and C samples was determined using ~ 16,000 gene microarrays. In the GRASP microarray studies, only those features (cDNA spots on the microarrays) behaving similarly (e.g. greater than 2-fold up-regulated in T relative to C) in all slides of the study will be reported to minimize false positives occurring due to dye bias and technical variability. Coho salmon transcripts responding reproducibly to GH transgenesis with and without feed rationing will be reported. Many of the microarray-identified hepatic transcripts responsive to GH transgenesis with and without rationing are involved in iron homeostasis, metabolism, cellular proliferation, and innate immunity. Keywords: Impact of growth hormone transgenesis with and without ration restriction on global hepatic gene expression Differential gene expression in R (ration-fed GH transgenic), T (ration-fed GH transgenic) and C (control non-transgenic) coho salmon liver samples was determined using the 16,006 gene (16K) GRASP cDNA microarrays. For each 16K microarray comparison (C vs. T, C vs. R, or T vs. R), 2 slides were hybridized (1 chip and 1 dye flip). Therefore, there were six slides total in this study. The C vs. T comparison consisted of slide EB017.061 (Cy3 = C, Cy5 = T) and its dye flip EB017.066 (Cy3 = T, Cy5 = C). The C vs. R comparison consisted of slide EB017.063 (Cy3 = R, Cy5 = C) and its dye flip EB017.064 (Cy3 = C, Cy5 = R). The T vs. R comparison consisted of slide EB017.062 (Cy3 = T, Cy5 = R) and its dye flip EB017.065 (Cy3 = R, Cy5 = T).