Transcription of the heat shock 70 locus in Trypanosoma brucei

The 23-kb heat shock 70 locus of the protozoan parasite Trypanosoma brucei encodes several tightly clustered genes. From 5' to 3', a cognate hsp70 gene (gene 1) (see preceding paper, Lee et al.) is separated from a cluster of five identical hsp70 genes (genes 2-6) by about 6 kb of DNA that encodes several RNAs of unknown function. Polycistronic transcripts could be detected in the tandem array of hsp70 genes 2-6 and the maturation of the hsp70 pre-mRNAs involves addition of mini-exons on at least two different alternate 3' splice acceptor sites. Potential heat shock transcription factor binding sites are present upstream of hsp70 gene 2 and in the intergenic regions of hsp70 genes 2-6, but could not be found upstream of the cognate hsp70 gene 1.