The heat-shock response in Trypanosoma cruzi and Crithidia fasciculata

RESUMO

Molecular aspects of heat-shock response were investigated in monogenetic and digenetic members of the Trypanosomatidae and the data obtained compared. Trypanosoma cruzi and Crithidia fasciculata differ in the number of heat-shock proteins (HSPs) induced and in the range of supra-optimal temperature induction of these proteins. Whereas low molecular weight Hsps were induced by high temperature in Crithidia, this effect was only seen in T. cruzi after ethanol treatment. The 61 kDa peptide of T. cruzi, induced by heat, was characterized as a HSP60 family member by Western blot using a Mycobacterium polyclonal anti-HSP60 antibody. The HSP61 aa. sequence, deduced from the isolated HSP60 gene and its mRNA product were characterized. The predicted aa. sequence has shown the presence of a mitochondrial peptide leader and no large domains of aa. sequence conservation were found when compared to other known HSP60, in contrast to what is observed in HSP70. Furthermore, the HSP60 gene is apparently conserved in T. cruzi, C. fascilulata and Leishmania as suggested by genomic Southern blot analysis.