RNA polymerase I holoenzymes

Abstract In eukaryotes, holoenzymes are large preassembled complexes containing RNA polymerases and variable sets of general transcription initiation factors and cofactors that are important for the regulation of gene expression. Recent advances in purification and characterization of RNA polymerase I holoenzyme from plants provide experimental data suggesting that it plays a key role in transcriptional regulation. These findings have a significant implication on our understanding of the mechanisms of promoter recognition, assembly of transcription initiation complexes, RNA chain elongation and transcription termination.