Related Experiment Video
Updated: Jun 17, 2025
04:04
Real-Time Quantification of the Effects of IS200/IS605 Family-Associated TnpB on Transposon Activity
Published on: January 20, 2023
2.3K
Distinct horizontal transfer mechanisms for type I and type V CRISPR-associated transposons
Kuang Hu1, Chia-Wei Chou2, Claus O Wilke3
1Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA. kh36969@utexas.edu.
Nature Communications
|August 5, 2024
Summary
Bacterial CASTs (CRISPR-associated transposons) can utilize defense CRISPR arrays for horizontal gene transfer. This finding is crucial for engineering CASTs for gene editing applications.
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- CRISPR-associated transposons (CASTs) facilitate gene transfer using CRISPR-associated proteins and Tn7 transposons.
- CASTs typically possess minimal CRISPR arrays and lack spacer acquisition capabilities.
Purpose of the Study:
- To investigate if CASTs can co-opt defense-associated CRISPR arrays for horizontal transmission.
- To understand the mechanisms and implications of CASTs utilizing heterologous CRISPR systems.
Main Methods:
- Bioinformatic analysis of CAST co-occurrence with defense CRISPR systems.
- Escherichia coli quantitative transposition assays.
- In vitro reconstitution experiments and high-resolution structural analysis.
Main Results:
- CASTs frequently co-occur with defense CRISPR systems, particularly type I-B and type V subtypes.
- CASTs can effectively use CRISPR RNAs from defense systems for transposition.
- Structural analysis revealed sequence-independent interactions between Cas6 and direct repeats.
- Type V CASTs exhibit unguided transposition and reduced off-target integration with specific co-factor over-expression.
Conclusions:
- Certain CASTs exploit defense-associated CRISPR arrays for horizontal gene transfer.
- This interaction necessitates careful consideration when transferring CASTs to new bacterial hosts.
- Findings guide the engineering of CASTs for enhanced activity and specificity in gene editing.
Related Concept Videos
02:13Overview of Transposition and Recombination
15.4K
Transposons make up a significant part of genomes of various organisms. Therefore, it is believed that transposition played a major evolutionary role in speciation by changing genome sizes and modifying gene expression patterns. For example, in bacteria, transposition can lead to conferring antibiotic resistance. Movement of transposable elements within the genetic pool of pathogenic bacteria can aid in transfer of antibiotic-resistant genetic elements. In eukaryotes, transposons can carry out...
15.4K
02:57DNA-only Transposons
14.4K
DNA-only transposons are called autonomous transposons since they code for the enzyme transposase that is required for the transposition mechanism. Insertion of transposons can alter gene functions in multiple ways. They can mutate the gene, alter gene expression by introducing a novel promoter or insulator sequence, introduce new splice sites, and change the mRNA transcripts produced, or remodel chromatin structure.
The donor site from where the transposon is excised is either degraded or...
The donor site from where the transposon is excised is either degraded or...
14.4K
03:08LTR Retrotransposons
17.4K
LTR retrotransposons are class I transposable elements with long terminal repeats flanking an internal coding region. These elements are less abundant in mammals compared to other class I transposable elements. About 8 percent of human genomic DNA comprises LTR retrotransposons. Some of the common examples of LTR retrotransposons are Ty elements in yeast and Copia elements in Drosophila.
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
17.4K
02:53CRISPR and crRNAs
16.9K
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...
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...
16.9K
02:18Types of Genetic Transfer Between Organisms
27.2K
Genetic transfer occurs when genetic information is passed from one organism to another. It occurs via two mechanisms: vertical gene transfer and horizontal gene transfer. Vertical gene transfer occurs when genetic information is transferred from one generation to the next, which happens much more frequently than horizontal gene transfer. Both sexual and asexual reproduction are forms of vertical gene transfer, where one or more organisms pass some or all of their genome onto their progeny.
27.2K
02:53Conservative Site-specific Recombination and Phase Variation
6.0K
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
6.0K