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Series GSE6944

Query DataSets for GSE6944

Status

Public on Nov 02, 2007

Title

Effect of starvation on global gene expression and proteolysis in rainbow trout (Oncorhynchus mykiss).

Platform organisms

Oncorhynchus mykiss; Salmo salar

Sample organism

Oncorhynchus mykiss

Experiment type

Expression profiling by array

Summary

BACKGROUND: Fast, efficiently growing animals have increased protein synthesis and/or reduced protein degradation relative to slow, inefficiently growing animals. Consequently, minimizing the energetic cost of protein turnover is a strategic goal for enhancing animal growth. Characterization of gene expression profiles associated with protein turnover would allow us to identify genes that could potentially be used as molecular biomarkers to select for germplasm with improved protein accretion. RESULTS: We evaluated changes in hepatic global gene expression in response to 3-week starvation in rainbow trout (Oncorhynchus mykiss). Microarray analysis revealed a coordinated, down-regulated expression of protein biosynthesis genes in starved fish. In addition, the expression of genes involved in lipid metabolism/transport, aerobic respiration, blood functions and immune response were decreased in response to starvation. However, the microarray approach did not show a significant increase of gene expression in protein catabolic pathways. Further studies, using real-time PCR and enzyme activity assays, were performed to investigate the expression of genes involved in the major proteolytic pathways including calpains, the multi-catalytic proteasome and cathepsins. Starvation reduced mRNA expression of the calpain inhibitor, calpastatin long isoform (CAST-L), with a subsequent increase in the calpain catalytic activity. In addition, starvation caused a slight but significant increase in 20S proteasome activity without affecting mRNA levels of the proteasome genes. Neither the mRNA levels nor the activities of cathepsin D and L were affected by starvation. CONCLUSION: These results suggest a significant role of calpain and 20S proteasome pathways in protein mobilization as a source of energy during fasting and a potential association of the CAST-L gene with fish protein accretion.
Keywords: Stress response

Overall design

We evaluated changes in hepatic global gene expression in response to 3-week starvation in rainbow trout. Microarray analysis revealed a coordinated, down-regulated expression of protein biosynthesis genes in starved fish. In addition, genes of lipid metabolism/transport, aerobic respiration, blood functions and immune response were decreased in response to starvation. However, the microarray approach did not reveal a significant increase of gene expression in protein catabolic pathways. Further studies using real-time PCR and enzyme activity assays were performed to investigate the gene expression patterns of the major proteolytic pathways, cathepsins, calpains and the multi-catalytic proteasome. Feed restriction reduced mRNA accumulation of the calpain inhibitor, calpastatin (CAST), with a subsequent increase in the calpain catalytic activity. In addition, starvation caused a slight but significant increase in 20S proteasome activity without affecting mRNA levels of the proteasome genes suggesting a post-transcriptional action. Starvation did not affect activities or mRNA accumulation of cathepsin D and L.

Contributor(s)

Salem M, Silverstein J, Rexroad III CE, Yao J

Citation(s)

17880706

Submission date

Feb 02, 2007

Last update date

Sep 18, 2012

Contact name

Mohamed Salem

E-mail(s)

mosalem@mail.wvu.edu