Sequence and genomic organization of the hsp70 genes of Leishmania amazonensis

The sequence and genomic organization of hsp70 genes in Leishmania amazonensis were examined. Maps of overlapping cosmid clones revealed that seven L. amazonensis hsp70 genes are organized into a 24-kb locus containing 3.5-kb tandem repeats. Cosmids covering a different chromosomal region indicated that an eighth hsp70 sequence is located at a distant site. Southern blot data suggested the existence of additional hsp70 genes or pseudogenes. One complete 3.5-kb genomic repeat unit, including coding and intergenic regions, was sequenced. The predicted L. amazonensis HSP70 protein had approximately 95% sequence identity with Leishmania donovani or Leishmania major HSP70, 81-85% identity with trypanosome HSP70, and 68 or 72% identity with human HSP70 or HSP70 cognate, respectively. The GGMP tetrapeptide repeat found in other trypanosomatid HSP70 proteins is absent from the L. amazonensis sequence. Intergenic sequences of L. amazonensis and L. major differed mainly in the presence of short gaps in the L. amazonensis sequence. Potential regulatory heat shock elements were identified in the upstream sequence. Several cDNA clones were also isolated, and two different poly(A) addition sites 100 nucleotides apart were identified.