Post-mortem changes in gene expression of the muscle tissue of rainbow trout, Oncorhynchus mykiss.

A subtracted cDNA library was used to identify specific genes that increase in post-mortem muscle of rainbow trout (Oncorhynchus mykiss) during on-ice storage. Of the 200 cDNAs analyzed, 82 had significant homologies to previously identified genes from salmonids and other species such as homologues of troponin I, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and so on, whereas 40 had no significant homologies and were designated as unknown. Comparison of gene expression profiles by dot blot hybridization confirmed an increase or induction of mRNA in the muscle after 3 h of on-ice storage compared to that at 0 h after death. Real-time reverse transcriptase-Polymerase Chain Reaction analysis showed that troponin I and GAPDH mRNAs were increased by 24 h and, in particular, that the change in troponin I mRNA was greater than that of GAPDH mRNA. These results suggest that the increased mRNAs in rainbow trout muscle occurred by transcription immediately after death.