SINGLE-STRANDED DNA-PROTEIN BINDING IN THE PROCYCLIC ACIDIC REPETITIVE PROTEIN (PARP) PROMOTER OF TRYPANOSOMA-BRUCEI

We performed gel retardation analyses of DNA-protein interactions using DNA from the procyclic acidic repetitive protein (PARP) promoter of the protozoan parasite Trypanosoma brucei. The PARP genes of Trypanosoma brucei are transcribed in an a-amanitin resistant manner, and it has been proposed that RNA polymerase I, rather than RNA polymerase II, transcribes the PARP genes [11]. Double-stranded restriction fragments containing the essential PARP-promoter regions bound only sequence-nonspecific nuclear factors, even though protein factors that bind specifically to double-stranded DNA from the snRNA U2 promoter were present in the extracts. In constrast, single-stranded DNA-binding proteins bound with high affinity, nucleotide-sequence and strand-specificity to the -69/-55 element and the coding and non-coding strands of the -37/-11 element.