CRISPR/Cas System and Factors Affecting Its Precision and Efficiency

The diverse applications of genetically modified cells and organisms require more precise and efficient genome-editing tool such as clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas). The CRISPR/Cas system was originally discovered in bacteria as a part of adaptive-immune system with multiple types. Its engineered versions involve multiple host DNA-repair pathways in order to perform genome editing in host cells. However, it is still challenging to get maximum genome-editing efficiency with fewer or no off-targets. Here, we focused on factors affecting the genome-editing efficiency and precision of CRISPR/Cas system along with its defense-mechanism, orthologues, and applications.

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Programming Native CRISPR Arrays for the Generation of Targeted Immunity

mBio ◽

10.1128/mbio.00202-16 ◽

2016 ◽

Vol 7 (3) ◽

Cited By ~ 15

Author(s):

Alexander P. Hynes ◽

Simon J. Labrie ◽

Sylvain Moineau

Keyword(s):

Immune System ◽

Nucleic Acid ◽

Genome Editing ◽

Dna Sequence ◽

Adaptive Immune System ◽

Natural Process ◽

The Public ◽

Adaptive Immune ◽

Public Consciousness ◽

Industrial Settings

ABSTRACT The adaptive immune system of prokaryotes, called CRISPR-Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated genes), results in specific cleavage of invading nucleic acid sequences recognized by the cell’s “memory” of past encounters. Here, we exploited the properties of native CRISPR-Cas systems to program the natural “memorization” process, efficiently generating immunity not only to a bacteriophage or plasmid but to any specifically chosen DNA sequence. IMPORTANCE CRISPR-Cas systems have entered the public consciousness as genome editing tools due to their readily programmable nature. In industrial settings, natural CRISPR-Cas immunity is already exploited to generate strains resistant to potentially disruptive viruses. However, the natural process by which bacteria acquire new target specificities (adaptation) is difficult to study and manipulate. The target against which immunity is conferred is selected stochastically. By biasing the immunization process, we offer a means to generate customized immunity, as well as provide a new tool to study adaptation.

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Repurposing CRISPR-Cas Systems as Genetic Tools for the Enterobacteriales

EcoSal Plus ◽

10.1128/ecosalplus.esp-0006-2020 ◽

2021 ◽

Author(s):

Nicholas Backes ◽

Gregory J. Phillips

Keyword(s):

Gene Regulation ◽

Immune System ◽

Gene Editing ◽

Defense Mechanism ◽

Adaptive Immune System ◽

Plasmid Curing ◽

Genetic Tools ◽

Adaptive Immune ◽

Domains Of Life ◽

Eukaryotic Genomes

Over the last decade, the study of CRISPR-Cas systems has progressed from a newly discovered bacterial defense mechanism to a diverse suite of genetic tools that have been applied across all domains of life. While the initial applications of CRISPR-Cas technology fulfilled a need to more precisely edit eukaryotic genomes, creative “repurposing” of this adaptive immune system has led to new approaches for genetic analysis of microorganisms, including improved gene editing, conditional gene regulation, plasmid curing and manipulation, and other novel uses.

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CRISPR systems: what’s new, where next?

The Biochemist ◽

10.1042/bio_2021_194 ◽

2021 ◽

Author(s):

Ashley Parkes ◽

Fiona Kemm ◽

Liu He ◽

Tom Killelea

Keyword(s):

Dna Repair ◽

Immune System ◽

Genetic Engineering ◽

Gene Editing ◽

Adaptive Immune System ◽

Feature Article ◽

Adaptive Immune ◽

The Past ◽

Domains Of Life ◽

Made In

The genetic signature of natural CRISPR-Cas systems were first noted in a 1989 publication and were characterized in detail from 2002 to 2007, culminating in the first report of a prokaryotic adaptive immune system. Since then, CRISPR-Cas enzymes have been adapted into molecular biology tools that have transformed genetic engineering across domains of life. In this feature article, we describe origins, uses and futures of CRISPR-Cas enzymes in genetic engineering: we highlight advances made in the past 10 years. Central to these advances is appreciation of interplay between CRISPR engineering and DNA repair. We highlight how this relationship has been manipulated to create further advances in the development of gene editing.

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CRISPR/Cas-Systems: characteristics and possibilities of use for editing bacterial genomes

Bacteriology ◽

10.20953/2500-1027-2020-2-38-48 ◽

2020 ◽

Vol 5 (2) ◽

pp. 38-48

Author(s):

I.A. Blatov ◽

◽

A.S. Shchurova ◽

D.Yu. Guschin ◽

S.D. Zvereva ◽

...

Keyword(s):

Immune System ◽

Genome Editing ◽

Bacterial Species ◽

Adaptive Immune System ◽

Bacterial Genomes ◽

Modern Biology ◽

Adaptive Immune ◽

History Of ◽

Genomic Editing ◽

Classification Structure

CRISPR-Cas is the adaptive immune system of bacteria and archaea. Since 2012, when the first opportunity to use the CRISPR/Cas system for genome editing was realized, the number of studies in this area has been growing rapidly. Today, genomic editing to modify specific regions of the genomes of various organisms is considered one of the key methodologies of modern biology. This review is devoted to the history of discovery, classification, structure, operational mechanisms of CRISPRCas systems and strategies for editing the genomes of various bacterial species using this technology. Key words: genome editing, genome, CRISPR-Cas system, bacteria

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Interactions Between Allogeneic Mesenchymal Stromal Cells and the Recipient Immune System: A Comparative Review With Relevance to Equine Outcomes

Frontiers in Veterinary Science ◽

10.3389/fvets.2020.617647 ◽

2021 ◽

Vol 7 ◽

Author(s):

J. Lacy Kamm ◽

Christopher B. Riley ◽

Natalie Parlane ◽

Erica K Gee ◽

C. Wayne McIlwraith

Keyword(s):

Immune System ◽

Mesenchymal Stromal Cells ◽

Stromal Cells ◽

Adaptive Immune System ◽

Host Cells ◽

Delayed Response ◽

Adaptive Immune ◽

Inherent Risk ◽

System A ◽

Comparative Review

Despite significant immunosuppressive activity, allogeneic mesenchymal stromal cells (MSCs) carry an inherent risk of immune rejection when transferred into a recipient. In naïve recipients, this immune response is initially driven by the innate immune system, an immediate reaction to the foreign cells, and later, the adaptive immune system, a delayed response that causes cell death due to recognition of specific alloantigens by host cells and antibodies. This review describes the actions of MSCs to both suppress and activate the different arms of the immune system. We then review the survival and effectiveness of the currently used allogeneic MSC treatments.

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Editor's cut: DNA cleavage by CRISPR RNA-guided nucleases Cas9 and Cas12a

Biochemical Society Transactions ◽

10.1042/bst20190563 ◽

2019 ◽

Vol 48 (1) ◽

pp. 207-219 ◽

Cited By ~ 2

Author(s):

Thomas Swartjes ◽

Raymond H.J. Staals ◽

John van der Oost

Keyword(s):

Immune System ◽

Genome Editing ◽

Dna Cleavage ◽

Adaptive Immune System ◽

New Developments ◽

Biochemical Characteristics ◽

Base Editing ◽

Dna Cleaving ◽

Adaptive Immune ◽

General Method

Discovered as an adaptive immune system of prokaryotes, CRISPR–Cas provides many promising applications. DNA-cleaving Cas enzymes like Cas9 and Cas12a, are of great interest for genome editing. The specificity of these DNA nucleases is determined by RNA guides, providing great targeting adaptability. Besides this general method of programmable DNA cleavage, these nucleases have different biochemical characteristics, that can be exploited for different applications. Although Cas nucleases are highly promising, some room for improvement remains. New developments and discoveries like base editing, prime editing, and CRISPR-associated transposons might address some of these challenges.

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