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

CRISPR and crRNAs02:53

CRISPR and crRNAs

19.5K
Bacteria and archaea are susceptible to viral infections just like eukaryotes; therefore, they have developed a unique adaptive immune system to protect themselves. Clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins (CRISPR-Cas) are present in more than 45% of known bacteria and 90% of known archaea.
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
19.5K
The Antiviral System of Bacteria and Archaea: CRISPR01:23

The Antiviral System of Bacteria and Archaea: CRISPR

960
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats is a adaptive immune system found in bacteria and archaea that protects against viral infections. This system enables prokaryotic cells to identify, remember, and neutralize foreign genetic elements, primarily bacteriophages, by storing fragments of the invader’s DNA as a genetic memory.The CRISPR immune response begins during an initial infection. Cas (CRISPR-associated) proteins play a central role in this...
960
CRISPR01:59

CRISPR

58.9K
Genome editing technologies allow scientists to modify an organism’s DNA via the addition, removal, or rearrangement of genetic material at specific genomic locations. These types of techniques could potentially be used to cure genetic disorders such as hemophilia and sickle cell anemia. One popular and widely used DNA-editing research tool that could lead to safe and effective cures for genetic disorders is the CRISPR-Cas9 system. CRISPR-Cas9 stands for Clustered Regularly Interspaced...
58.9K
CRISPR01:59

CRISPR

18.8K
18.8K
CRISPR/Cas9 Genome Editing01:28

CRISPR/Cas9 Genome Editing

2.5K
The CRISPR-Cas system serves as a bacterial defense mechanism against invading genetic elements such as viruses and plasmids, forming the foundation for its adaptation as a powerful genome-editing tool. Originally discovered in prokaryotes, this system has been repurposed to revolutionize genetic engineering across a wide range of organisms, including plants, animals, and humans. The core component, Cas9, is an endonuclease derived from Streptococcus pyogenes, capable of introducing...
2.5K
Homologous Recombination02:31

Homologous Recombination

65.2K
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
65.2K

You might also read

Related Articles

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

Sort by
Same author

Target RNA-triggered CRISPR-Cas12a2 preferentially cleaves collateral DNA over RNA.

Nucleic acids research·2026
Same author

YprA-family helicases provide the missing link between diverse prokaryotic immune systems.

Cell host & microbe·2026
Same author

Are We Making Genetically Modified Humans?

The CRISPR journal·2026
Same author

Target RNA-triggered CRISPR-Cas12a2 Preferentially Cleaves Collateral DNA over RNA.

bioRxiv : the preprint server for biology·2026
Same author

Reply to Z Yu and F Qin.

The American journal of clinical nutrition·2026
Same author

Guide DNA - not RNA - expands the CRISPR toolkit.

Nature biotechnology·2026

Related Experiment Video

Updated: Mar 23, 2026

Efficient PAM-Less Base Editing for Zebrafish Modeling of Human Genetic Disease with zSpRY-ABE8e
07:31

Efficient PAM-Less Base Editing for Zebrafish Modeling of Human Genetic Disease with zSpRY-ABE8e

Published on: February 17, 2023

1.7K

Identifying and Visualizing Functional PAM Diversity across CRISPR-Cas Systems.

Ryan T Leenay1, Kenneth R Maksimchuk1, Rebecca A Slotkowski1

  • 1Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.

Molecular Cell
|April 5, 2016
PubMed
Summary

This study introduces two new tools, PAM-SCANR and the PAM wheel, designed to identify and visualize the specific DNA sequences, known as protospacer-adjacent motifs, that CRISPR-Cas proteins require to recognize and edit target genetic material.

Keywords:
gene editingDNA recognitionprotein engineeringmicrobial immunity

Frequently Asked Questions

More Related Videos

Pooled CRISPR-Based Genetic Screens in Mammalian Cells
09:05

Pooled CRISPR-Based Genetic Screens in Mammalian Cells

Published on: September 4, 2019

23.5K
Functional Assessment of BRCA1 variants using CRISPR-Mediated Base Editors
09:22

Functional Assessment of BRCA1 variants using CRISPR-Mediated Base Editors

Published on: February 28, 2021

6.0K

Related Experiment Videos

Last Updated: Mar 23, 2026

Efficient PAM-Less Base Editing for Zebrafish Modeling of Human Genetic Disease with zSpRY-ABE8e
07:31

Efficient PAM-Less Base Editing for Zebrafish Modeling of Human Genetic Disease with zSpRY-ABE8e

Published on: February 17, 2023

1.7K
Pooled CRISPR-Based Genetic Screens in Mammalian Cells
09:05

Pooled CRISPR-Based Genetic Screens in Mammalian Cells

Published on: September 4, 2019

23.5K
Functional Assessment of BRCA1 variants using CRISPR-Mediated Base Editors
09:22

Functional Assessment of BRCA1 variants using CRISPR-Mediated Base Editors

Published on: February 28, 2021

6.0K

Area of Science:

  • Genomics and bioinformatics research within CRISPR-Cas systems
  • Molecular biology investigating functional PAM diversity mechanisms

Background:

No prior work had resolved the full breadth of sequence requirements for diverse prokaryotic immune proteins. Researchers often struggle to map how specific DNA motifs influence the efficacy of gene editing tools. It was already known that these systems rely on short flanking sequences for target recognition. This gap motivated the development of standardized screening methods to classify these interactions across species. Prior research has shown that different protein families exhibit distinct preferences for these recognition sites. That uncertainty drove the need for a unified approach to compare functional landscapes. Scientists previously lacked a clear way to represent the complex data generated by high-throughput screening experiments. This study addresses these limitations by providing a scalable framework for characterizing diverse microbial immune mechanisms.

Purpose Of The Study:

The aim of this work is to develop a robust platform for identifying and visualizing functional DNA recognition motifs in prokaryotic immune systems. Researchers sought to address the difficulty of characterizing these sequences across a wide variety of protein families. They aimed to create a tunable screening method that could accurately distinguish between active and inactive motifs. The study also intended to provide a clear, interactive way to represent complex sequence-activity data. This motivation arose from the need to better understand the diversity of natural gene editing tools. The authors wanted to ensure their tools were applicable to both new experiments and existing data sets. By integrating these approaches, they hoped to accelerate the discovery of novel recognition requirements. This effort provides a foundation for more efficient exploitation of diverse microbial systems in biotechnology.

Main Methods:

The review approach involved developing a novel in vivo screening platform for identifying functional DNA recognition motifs. Investigators utilized a positive, tunable selection system based on NOT-gate repression logic. This design allowed for the precise quantification of sequence activity within living microbial cells. The team applied this technique to characterize four distinct prokaryotic immune protein families. They also created a graphical visualization scheme to represent the resulting sequence-activity data. This scheme was tested against existing high-throughput data sets to ensure broad applicability. The researchers integrated these two components to provide a comprehensive workflow for motif discovery. This methodology enabled the systematic mapping of complex landscapes across various bacterial species.

Main Results:

The strongest finding demonstrates that the screening platform successfully identifies functional recognition motifs across diverse protein families. The researchers mapped complex sequence-activity landscapes for the I-C, I-E, II-A, and V-A systems. Their data revealed specific activity profiles for Bacillus halodurans, Escherichia coli, Streptococcus thermophilus, and Francisella novicida. The visualization scheme effectively conveyed individual sequence activities for these four distinct systems. Furthermore, the team applied their graphical tool to existing data sets for SpyCas9 and SauCas9. This application garnered new insights into the diversity of recognition motifs for these widely used proteins. The results confirm that the platform is compatible with different experimental inputs. These findings provide a robust framework for characterizing the functional requirements of various immune systems.

Conclusions:

The authors propose that their screening platform effectively maps the functional requirements of various prokaryotic immune proteins. Their synthesis suggests that the visualization scheme provides a clear representation of complex sequence-activity relationships. The researchers claim that these tools successfully validate known recognition motifs across multiple bacterial species. They indicate that the platform remains compatible with existing high-throughput data sets for broader analysis. The study implies that these methods facilitate a deeper understanding of how different proteins interact with their target DNA. The authors state that their approach accelerates the characterization of naturally occurring immune systems. They conclude that the integrated workflow offers a robust solution for future exploration of diverse gene editing components. The findings suggest that these strategies improve the ability to exploit various systems for biotechnological applications.

The researchers propose that PAM-SCANR functions as an in vivo, positive, and tunable screen. It utilizes a NOT-gate repression mechanism to identify active protospacer-adjacent motifs, distinguishing them from inactive sequences by measuring the resulting gene expression levels in the host cells.

The PAM wheel serves as an interactive visualization scheme. It displays individual DNA sequences alongside their corresponding activity levels, allowing users to interpret complex sequence-activity landscapes that are otherwise difficult to discern from raw tabular data outputs.

The authors state that the screen is necessary to elucidate functional motifs across diverse systems. It allows for the systematic comparison of Bacillus halodurans, Escherichia coli, Streptococcus thermophilus, and Francisella novicida, which would be technically challenging to achieve using traditional, non-tunable screening methods.

The screen acts as the primary data generation component, while the wheel serves as the visualization tool. The former identifies functional sequences through biological selection, whereas the latter organizes these results into a graphical format for comparative analysis across different species.

The researchers measured the activity landscapes for four distinct systems. They observed specific sequence preferences for the I-C, I-E, II-A, and V-A types, revealing that each protein family maintains a unique profile of target recognition requirements.

The authors claim that these tools offer powerful means of understanding and exploiting the multitude of systems in nature. They suggest that this approach will accelerate the discovery and application of new gene editing technologies derived from prokaryotic immune pathways.