The cellular heat shock response in kinetoplastid protozoa is regulate
d exclusively at a post-transcriptional level. The heat-inducibility o
f heat shock protein synthesis is retained under actinomycin C-1 which
indicates an inducible translation of heat shock mRNAs. We have also
assessed the ability of various chemicals known to be effective trigge
rs of the heat shock response in higher eukaryotes to induce heat shoc
k protein synthesis in Leishmania donovani. None of the tested chemica
ls elicited a stress response. We propose that the lack of transcripti
on regulation in the kinetoplastida precludes a stress response under
chemical stress.