Immunogen sequence: EPSSAGAQAA EEPSGAGSEE LIKSDQVNGV LVLSLLDKII GAVDQIQLTQ AQLEERQAEM EGAVQSIQGE LSKLGK. The polymerase I and transcript release factor (PTRF) enables the dissociation of paused ternary polymerase I transcription complexes from the 3' end