Molecular cloning and characterization of a constitutively expressed heat‐shock‐cognate hsc71 gene from rainbow trout

A rainbow trout major heat‐shock‐protein‐like gene (hsp 70) and corresponding cDNA clones were isolated by hybridization to heterologous hsp70 probes. DNA sequencing revealed that this gene is structurally similar to a mammalian heat‐shock‐cognate hsc70 gene and consists of eight introns. Northern blot and primer extension analyses showed that the corresponding mRNA is constitutively abundant in different trout tissues and salmonid cell lines. Fragments of the isolated gene containing the −900 –+30 and −217 –+58 sequence were linked to a bacterial chloramphenicol acetyltransferase reporter gene and transiently transfected into salmonid cells. The expression pattern of these constructs supports our conclusion that the isolated genomic and cDNA clones correspond to a trout heat‐shock‐cognate hsc70 gene.