2011 Annual Report
The cDNAs for rainbow trout cyclin B1 (CB1), cyclin B2 (CB2) and Cdc2 kinase were cloned and their expression profiles characterized during oogenesis and spermatogenesis. A number of novel oocyte-specific genes were identified from a rainbow trout oocyte cDNA library. One of them encodes a protein (OORP-T) with a conserved oxysterol binding protein (OSBP) domain, suggesting a role of this protein in the synthesis, transportation and metabolism of lipids during oogenesis and embryogenesis. Another novel transcript appears to be a noncoding mRNA-like transcript (RtGST-1). Expression of this transcript is extremely high in early previtellogenic ovaries, suggesting a role of this transcript in differentiation and/or development of germ cells. The expression patterns of 9 transcription factors were characterized during early embryonic development. Cloning and characterization of these key oocyte-expressed genes may lead to the discovery of new candidate genes associated with oocyte competence and embryonic survival in rainbow trout.
To identify genes that could potentially be used as molecular biomarkers to study protein turnover and select for germplasm with improved protein accretion in rainbow trout, microarray technology was used to identify genes/pathways involved in starvation-related protein turnover. A coordinated down- regulation of the protein biosynthesis genes in starved fish was observed. Further study using real-time PCR and enzyme activity assays revealed a reduction of calpastatin mRNA with an increase in the calpain catalytic activity in starved fish. Using microarray analysis, gene expression profiles between atrophy muscle from 2N fish and normal muscle from 3N sterile fish was compared. Muscle atrophy was associated with elevated expression of genes involved in the catheptic and collagenase proteolytic pathways, the aerobic production, utilization of ATP and growth arrest; and down-regulated expression of genes encoding enzymes of anaerobic respiration, muscle proteins as well as factors involved in RNA and protein biosynthesis/processing.
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