COMPLEMENTARY-DNA CLONING OF HSC71, A 71 KDA HEAT-SHOCK COGNATE PROTEIN, IN JAPANESE FLOUNDER PARALICHTHYS-OLIVACEUS

Full-length cDNA for a 71 kDa constitutively expressed heat-shock-cogn ate protein (HSC71), a member of the HSP70 family, was isolated from a Japanese flounder embryo cDNA library. It has a single ORF of 1950bp that encodes a protein of 71.2 kDa. Japanese flounder HSC71 contains a EEVD (Glu-Glu-Val-Asp) peptide motif at the C-terminal end which is a common feature of cytosolic HSC proteins in the HSP70 family. Japanes e flounder HSC;71 is 96.0%, 93.9%, 93.5%, and 93.4% identical in prima ry structure to rainbow trout HSC71, bovine HSC71, rat HSC71, and huma n HSC71, respectively. These results suggest that the HSC71 amino acid sequence has been highly conserved among vertebrates. Northern blot a nalysis showed that HSC71 mRNA was expressed constitutively in the Jap anese flounder cells in early passage regardless of heat shock treatme nt.