THE DNAJ60 GENE OF DROSOPHILA-MELANOGASTER ENCODES A NEW MEMBER OF THE DNAJ FAMILY OF PROTEINS

In eukaryotes the DnaJ homolog constitute a family of proteins with di verse functions which all appear to involve the chaperone activity of Hsp70. Here, we report the molecular characterization of DnaJ60, a gen e located at 60C on the right arm of the second chromosome of Drosophi la melanogaster and encoding a putative protein of 217 amino acids wit h a molecular mass of 27.7-kDa and a pI of 10.5. The N-terminal region of the DnaJ60 protein displays a significant sequence similarity with the J domain of DnaJ proteins and contains a centrally located hydrop hobic segment suggesting the occurrence of a membrane spanning domain. Northern blot analysis detected a 0.75-kb transcript which is weakly expressed in embryos, larvae and females but intensively expressed in adult males. In situ localization revealed that the DnaJ60 transcript is highly expressed in male testes and the ejaculary bulb but at an un detectable level in ovaries suggesting that the DnaJ60 protein may pla y an important function during spermatogenesis and/or in the male geni tal tract.