CLONING AND CHARACTERIZATION OF CDNAS FOR 70-KDA HEAT-SHOCK PROTEINS (HSP70) FROM 2 FISH SPECIES OF THE GENUS ORYZIAS

cDNA corresponding to two hsp70-related genes (OLHSC70 and CEHSC70) we re isolated from two lines of cultured fish cells derived from the gen us Oryzias. OLHSC70 was 2,261 bp in length and encoded a protein of 68 6 amino acids with a predicted molecular mass of 76,120 daltons. CEHSC 70 was 2,114 bp in length and it lacked the 5' region found in OLHSC70 . Two-dimensional electrophoresis revealed that Oryzias latipes has at least three heat-inducible proteins with molecular masses of about 70 ,000 daltons. One of these proteins (Hsp70.1) was barely expressed und er normal conditions but its high-level expression was induced by hype rthermia. The other two proteins (Hsc70.1, and Hsc70.2) were constitut ively expressed under normal conditions and only slightly enhanced lev els were induced by hyperthermia. Transfection with the cloned sequenc e, RNA dot-blot analysis and the two-dimensional electrophoresis of pr oteins showed that OLHSC70 encoded Hsc70.1.