Sequence specific interaction of 5'upstream regulatory sequences of the falcipain genes with parasite nuclear factors. (A) Schematic representation of the probes used for EMSAs. Short lines indicate the relative positions of double stranded nucleotide probes used in EMSA. Astericks denote those probes that formed complexes with nuclear extracts. (B) Electrophoretic mobility shift assay. End labeled double-stranded oligonucleotides were incubated with 2–5 μg of nuclear proteins isolated from asynchronous parasite culture. For competition experiments, a 100 fold excess of the respective unlabelled double-stranded oligonucleotides were used. Arrows indicate the positions of DNA-protein complexes.