A DNA-binding protein is required for termination of transcription by RNA polymerase I in Xenopus laevis

We describe a partially fractionated in vitro transcription system from Xenopus laevis for the assay of transcription termination by RNA polymerase I. Termination in vitro was found to require a specific terminator sequence in the DNA and a DNA-binding protein fraction that produces a footprint over the terminator sequence.