Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Ribosomal RNA Synthesis02:53

Ribosomal RNA Synthesis

13.2K
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
13.2K
Ribozymes02:47

Ribozymes

12.3K
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can...
12.3K
RNA Polymerase II Accessory Proteins02:36

RNA Polymerase II Accessory Proteins

9.2K
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...
9.2K
Protein Complex Assembly02:41

Protein Complex Assembly

10.6K
Proteins can form homomeric complexes with another unit of the same protein or heteromeric complexes with different types.  Most protein complexes self-assemble spontaneously via ordered pathways, while some proteins need assembly factors that guide their proper assembly. Despite the crowded intracellular environment, proteins usually interact with their correct partners and form functional complexes.
Many viruses self-assemble into a fully functional unit using the infected host cell to...
10.6K
Eukaryotic RNA Polymerases00:58

Eukaryotic RNA Polymerases

24.3K
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...
24.3K
Transcription Initiation01:47

Transcription Initiation

16.5K
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...
16.5K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

A ribozyme ligase that requires a 3' terminal phosphate on its RNA substrate.

Nature communications·2026
Same author

Screen Time and Nutrition in Adolescents: Emerging Evidence on Health and Behavioral Outcomes.

Academic pediatrics·2026
Same author

A nucleic acid labeling chemistry reveals surface DNA on exosomes.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same author

Ultraviolet-driven self-repair in chimeric d(GAUU) outcompetes damage formation.

Chemical communications (Cambridge, England)·2026
Same author

Mg<sup>2+</sup> Catalyzes Nonenzymatic RNA Primer Extension through a Concerted Outer-Sphere Mechanism.

Journal of the American Chemical Society·2026
Same author

Immunogenicity and safety of co-administration of a recombinant shingles vaccine with an mRNA COVID-19 or adjuvanted influenza vaccine: a randomised controlled trial.

The Journal of infection·2026

Related Experiment Video

Updated: Jul 18, 2025

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
10:59

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events

Published on: May 13, 2019

9.8K

Molecular Crowding Facilitates Ribozyme-Catalyzed RNA Assembly.

Saurja DasGupta1,2,3, Stephanie Zhang1,4, Jack W Szostak1,2,3,4

  • 1Department of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.

ACS Central Science
|August 28, 2023
PubMed
Summary

Molecular crowding enables ribozymes to function in low magnesium conditions, crucial for early life. This finding supports the role of molecular crowding in primordial RNA catalysis and the origin of cellular life.

More Related Videos

Nanomanipulation of Single RNA Molecules by Optical Tweezers
06:59

Nanomanipulation of Single RNA Molecules by Optical Tweezers

Published on: August 20, 2014

14.9K
Optical Tweezers to Study RNA-Protein Interactions in Translation Regulation
12:26

Optical Tweezers to Study RNA-Protein Interactions in Translation Regulation

Published on: February 12, 2022

5.0K

Related Experiment Videos

Last Updated: Jul 18, 2025

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
10:59

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events

Published on: May 13, 2019

9.8K
Nanomanipulation of Single RNA Molecules by Optical Tweezers
06:59

Nanomanipulation of Single RNA Molecules by Optical Tweezers

Published on: August 20, 2014

14.9K
Optical Tweezers to Study RNA-Protein Interactions in Translation Regulation
12:26

Optical Tweezers to Study RNA-Protein Interactions in Translation Regulation

Published on: February 12, 2022

5.0K

Area of Science:

  • Origin of life studies
  • RNA biochemistry
  • Prebiotic chemistry

Background:

  • Ribozymes are essential for primordial biology but require high magnesium (Mg2+) concentrations for function.
  • High Mg2+ concentrations can degrade RNA and destabilize prebiotic cell membranes, posing challenges for early life.
  • Existing cellular environments maintain ribozyme activity at low Mg2+ (<1 mM) via molecular crowding.

Purpose of the Study:

  • To investigate molecular crowding as a strategy to enable ribozyme activity at low Mg2+ concentrations.
  • To explore conditions supporting ribozyme-catalyzed RNA assembly relevant to the origin of life.
  • To determine if molecular crowding can stabilize ribozyme function under denaturing conditions.

Main Methods:

  • Testing ribozyme-catalyzed RNA ligation with phosphorimidazolide substrates in the presence of polyethylene glycol (PEG).
  • Assessing ribozyme activity under denaturing conditions (alkaline pH, urea) with and without molecular crowding.
  • Evaluating the effect of crowding agents and prebiotically relevant small molecules on RNA-catalyzed polymerization of nucleoside triphosphates.

Main Results:

  • Polyethylene glycol significantly enhanced ribozyme-catalyzed RNA ligation at low Mg2+.
  • Molecular crowding preserved ribozyme ligase activity under alkaline pH and urea.
  • Crowding stimulated RNA-catalyzed RNA assembly, including nucleoside triphosphate polymerization, and was enhanced by small molecules like ethylene glycol, ribose, and amino acids.

Conclusions:

  • Molecular crowding is a viable mechanism to support ribozyme function at low Mg2+ concentrations, overcoming limitations of high cation requirements.
  • This finding has significant implications for understanding RNA-based catalysis in primordial environments and the emergence of early cellular life.
  • The study highlights the potential role of molecular crowding and simple organic molecules in facilitating prebiotic RNA replication and the origin of life.