Leishmania donovani heat shock protein 100 -: Characterization and function in amastigote stage differentiation

We report the cloning and molecular analysis of the Leishmania donovani clpB gene. The protein-coding region is highly conserved compared with its L. major homologue, while 5'-and 3'-flanking DNA sequences display considerable divergence, The encoded mRNA has an unusually long 5'-leader sequence typical for RNAs, which are translated preferentially under heat stress. The gene product, a 100-kDa heat shock protein, Hsp100, becomes abundant only during sustained heat stress, but not under common chemical stresses, Hsp100 associates into trimeric complexes and is found mostly in a cytoplasmic, possibly membrane-associated localization as deter mined by immune electron microscopy. Hsp100 shows immediate early expression kinetics during axenic amastigote development, In its absence, expression of at least one amastigote stage-specific protein family is impaired.