SYNTHESIS OF A UBIQUITOUSLY PRESENT NEW HSP60 FAMILY PROTEIN IS ENHANCED BY HEAT-SHOCK ONLY IN THE MALPIGHIAN TUBULES OF DROSOPHILA

A homologue of the chaperonin protein of the HSP60 family has not been shown so far in Drosophila. Using an antibody specific to HSP60 famil y protein in Western blotting and immunocytochemistry, we showed that a 64-kDa polypeptide, homologous to the HSP60, is constitutively prese nt in all tissues of Drosophila melanogaster throughout the life cycle from the freshly laid egg to all embryonic, larval and adult stages. A 64-kDa polypeptide reacting with the same antibody in Western blots is present in all species of Drosophila examined. Using Western blotti ng in conjunction with S-35-methionine labeling of newly synthesized p roteins and immuno-precipitation of the labeled proteins with HSP60-sp ecific antibody, it was shown that synthesis of the 64-kDa homologue o f HSP60 is appreciably increased by heat shock only in the Malpighian tubules, which are already known to lack the common HSPs.