Related Experiment Video
Updated: Oct 4, 2025
07:44
High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
14.4K
A structural perspective of human RNA polymerase III
Qianmin Wang1,2, Ming Lei1,2,3, Jian Wu1,2
1Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
RNA Biology
|February 8, 2022
Summary
Structural studies reveal the intricate organization of human RNA polymerase III (Pol III), a vital enzyme for non-coding RNA synthesis. Advances in cryo-electron microscopy provide unprecedented insights into this complex molecular machine.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- RNA polymerase III (Pol III) is a crucial enzyme in eukaryotes, synthesizing essential non-coding RNAs like tRNA and 5S rRNA.
- Human Pol III is a large, 17-subunit complex, presenting significant challenges for structural determination.
- Previous studies established the yeast Pol III structure in 2015, providing a foundational understanding.
Purpose of the Study:
- To review and discuss recent structural studies of human RNA polymerase III.
- To integrate new structural data with the known functions of Pol III in eukaryotic transcription.
- To highlight the impact of technological advancements on understanding human Pol III.
Main Methods:
- Cryo-electron microscopy (cryo-EM) has been pivotal in resolving the structure of human Pol III.
- Optimization of endogenous extract preparation and purification techniques were key.
- Comparative analysis of yeast and human Pol III structures.
Main Results:
- Recent cryo-EM studies have provided unprecedented details of human Pol III organization.
- The 17-subunit structure of human Pol III has been elucidated at near-atomic resolution.
- Structural insights reveal the arrangement of core and peripheral subunits.
Conclusions:
- Advances in cryo-EM have overcome previous limitations in studying large complexes like human Pol III.
- Structural understanding of human Pol III is crucial for comprehending eukaryotic transcription regulation.
- Continued structural and functional studies will further elucidate Pol III's role in cellular processes.
Related Concept Videos
00:58Eukaryotic RNA Polymerases
24.9K
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
All three eukaryotic RNAPs require specific transcription factors, of which the...
24.9K
01:47Transcription Initiation
17.2K
Initiation is the first step of transcription in eukaryotes. Prokaryotic RNA Polymerase (RNAP) can bind to the template DNA and start transcribing. On the other hand, transcription in eukaryotes requires additional proteins, called transcription factors, to first bind to the promoter region in the DNA template. This binding helps recruit the specific RNAP that can assemble on the DNA and start transcription.
The promoters and enhancers and their accessory proteins allow tight regulation of...
The promoters and enhancers and their accessory proteins allow tight regulation of...
17.2K
00:43Bacterial RNA Polymerase
30.8K
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
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...
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...
30.8K
02:36RNA Polymerase II Accessory Proteins
9.7K
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
9.7K
01:53Bacterial Transcription
30.3K
RNA polymerase (RNAP) carries out DNA-dependent RNA synthesis in both bacteria and eukaryotes. Bacteria do not have a membrane-bound nucleus. So, transcription and translation occur simultaneously, on the same DNA template.
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
30.3K
01:19RNA Structure
5.5K
The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA) involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three...
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA) involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three...
5.5K