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

Bacterial Transcription01:53

Bacterial Transcription

37.5K
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:
37.5K
Eukaryotic Transcription Activators02:42

Eukaryotic Transcription Activators

13.0K
Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These...
13.0K
Transcription Elongation Factors02:35

Transcription Elongation Factors

14.3K
Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not surprising that the elongation complex's composition also varies along the way while transcribing a gene.
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA...
14.3K
Transcription Elongation Factors02:35

Transcription Elongation Factors

5.0K
5.0K
Types of RNA01:20

Types of RNA

10.2K
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in regulating gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA Performs Diverse...
10.2K
Types of RNA01:23

Types of RNA

73.5K
Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
73.5K

You might also read

Related Articles

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

Sort by
Same author

Selective targeting of a histone-like silencer Sfx to the R6K conjugal transfer operon.

Nucleic acids research·2026
Same author

MACRO-MOLECULAR CROWDING FAVORS WRITHE IN UNWOUND DNA.

bioRxiv : the preprint server for biology·2026
Same author

Macromolecular crowding alters transcription: real-time measurements with SYBR Green II.

Research square·2026
Same author

Selective targeting of a histone-like silencer Sfx to the R6K conjugal transfer operon.

bioRxiv : the preprint server for biology·2026
Same author

Insights on the effect of macromolecular crowding on transcription and its regulation.

QRB discovery·2025
Same author

Force and the α-C-terminal domains bias RNA polymerase recycling.

Nature communications·2024

Related Experiment Video

Updated: Mar 6, 2026

DNA-Tethered RNA Polymerase for Programmable In vitro Transcription and Molecular Computation
09:26

DNA-Tethered RNA Polymerase for Programmable In vitro Transcription and Molecular Computation

Published on: December 29, 2021

4.9K

Proteins mediating DNA loops effectively block transcription.

Zsuzsanna Vörös1, Yan Yan1, Daniel T Kovari1

  • 1Department of Physics, Emory University, Atlanta, Georgia, 30322.

Protein Science : a Publication of the Protein Society
|March 16, 2017
PubMed
Summary

DNA looping by proteins like lac repressor (LacI) creates roadblocks for transcription. Looped DNA significantly enhances protein obstruction of RNA polymerases (RNAP), regardless of protein-DNA binding affinity.

Keywords:
DNA loopingRNAPlac repressor proteinmagnetic tweezersscanning force microscopytranscription elongation

More Related Videos

Estimation of Telomeric Repeat-containing RNA from DNA/RNA Hybrid Complexes
11:24

Estimation of Telomeric Repeat-containing RNA from DNA/RNA Hybrid Complexes

Published on: December 5, 2025

277
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

10.2K

Related Experiment Videos

Last Updated: Mar 6, 2026

DNA-Tethered RNA Polymerase for Programmable In vitro Transcription and Molecular Computation
09:26

DNA-Tethered RNA Polymerase for Programmable In vitro Transcription and Molecular Computation

Published on: December 29, 2021

4.9K
Estimation of Telomeric Repeat-containing RNA from DNA/RNA Hybrid Complexes
11:24

Estimation of Telomeric Repeat-containing RNA from DNA/RNA Hybrid Complexes

Published on: December 5, 2025

277
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

10.2K

Area of Science:

  • Molecular Biology
  • Genetics
  • Biophysics

Background:

  • Proteins binding to two separate DNA sites form loops, which can influence gene regulation and transcription.
  • The topological state of DNA, whether looped or linear, may affect how proteins act as obstacles to transcription machinery.
  • Understanding these interactions is crucial for deciphering gene expression control mechanisms.

Purpose of the Study:

  • To investigate how DNA looping by the lac repressor (LacI) affects its ability to block transcription by RNA polymerase (RNAP).
  • To determine if the topological structure of DNA influences the efficiency of protein-mediated transcriptional roadblocks.

Main Methods:

  • Utilized scanning force microscopy (SFM) to visualize in vitro transcription on DNA templates with two LacI operator sites.
  • Employed magnetic tweezers to record the behavior of transcription elongation complexes encountering LacI-bound DNA.
  • Varied LacI concentrations to generate both looped and unlooped DNA configurations.

Main Results:

  • On unlooped DNA, RNAP more frequently bypassed LacI at a lower affinity operator (O2) than a higher affinity operator (Os).
  • In looped DNA, LacI acted as a strong roadblock, halting RNAP independently of operator binding affinity.
  • Magnetic tweezers confirmed that RNAP paused for extended periods when encountering LacI, suggesting waiting for dissociation or a bypass mechanism.

Conclusions:

  • DNA looping significantly enhances the roadblock effect of proteins like LacI on transcription.
  • The topological state of DNA is a critical factor determining the impact of protein obstacles on RNAP progression.
  • These findings provide insights into the physical mechanisms of gene regulation and transcription interference.