Related Experiment Video
Updated: Feb 10, 2026

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
Published on: May 13, 2019
Distinct Mechanisms of Transcription Initiation by RNA Polymerases I and II
Christoph Engel1,2, Simon Neyer1, Patrick Cramer1
1Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
Abstract:
RNA polymerases I and II (Pol I and Pol II) are the eukaryotic enzymes that catalyze DNA-dependent synthesis of ribosomal RNA and messenger RNA, respectively. Recent work shows that the transcribing forms of both enzymes are similar and the fundamental mechanisms of RNA chain elongation are conserved. However, the mechanisms of transcription initiation and its regulation differ between Pol I and Pol II. Recent structural studies of Pol I complexes with transcription initiation factors provided insights into how the polymerase recognizes its specific promoter DNA, how it may open DNA, and how initiation may be regulated. Comparison with the well-studied Pol II initiation system reveals a distinct architecture of the initiation complex and visualizes promoter- and gene-class-specific aspects of transcription initiation. On the basis of new structural studies, we derive a model of the Pol I transcription cycle and provide a molecular movie of Pol I transcription that can be used for teaching.
Related Concept Videos
Eukaryotic RNA Polymerases
All three eukaryotic RNAPs require specific transcription factors, of which the...
Bacterial RNA Polymerase
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
RNA Polymerase II Accessory Proteins
Transcription Initiation
The promoters and enhancers and their accessory proteins allow tight regulation of...
Eukaryotic Transcription Activators
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These...
Transcription
Transcription is the process of synthesizing RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. Additionally, many other proteins and regulatory sequences are involved in the proper synthesis of messenger RNA (mRNA). Regulation of transcription is responsible for the differentiation of all the different types of cells and often for the proper cellular response to environmental signals.
Transcription Can Produce Different Kinds...

