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

2019 ◽  
Vol 48 (1) ◽  
pp. 207-219 ◽  
Author(s):  
Thomas Swartjes ◽  
Raymond H.J. Staals ◽  
John van der Oost

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.

mBio ◽  
2016 ◽  
Vol 7 (3) ◽  
Author(s):  
Alexander P. Hynes ◽  
Simon J. Labrie ◽  
Sylvain Moineau

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.


Bacteriology ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 38-48
Author(s):  
I.A. Blatov ◽  
◽  
A.S. Shchurova ◽  
D.Yu. Guschin ◽  
S.D. Zvereva ◽  
...  

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


Author(s):  
Stefan Magez ◽  
Joar Esteban Pinto Torres ◽  
Seoyeon Oh ◽  
Magdalena Radwanska

Salivarian trypanosomes are extracellular parasites affecting humans, livestock and game animals. Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense are human infective sub-species of T. brucei causing Human African Trypanosomosis (HAT - sleeping sickness). The related T. b. brucei parasite lacks the resistance to survive in human serum, and only inflicts animal infections. Animal Trypanosomosis (AT) is not restricted to Africa, but is present on all continents. T. congolense and T. vivax are the most widespread pathogenic trypanosomes in sub-Sahara Africa. Trough mechanical transmission, T. vivax has however been introduced into South America. T. evansi is a unique animal trypanosome that is found in vast territories around the world and can cause atypical Human Trypanosomosis (aHT). All salivarian trypanosomes are well adapted to survival inside the host’s immune system. This is not a hostile environment for these parasite, but this is the place where they thrive. Here we provide an overview of the latest insights into the host-parasite interaction and the unique survival strategies allowing trypanosomes to outsmart the immune system. In addition, we review new developments in treatment and diagnosis as well the issues that have hampered the development of field-applicable anti-trypanosome vaccines for the implementation of sustainable disease control.


Author(s):  
Nasir Javaid ◽  
Sangdun Choi

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.


2016 ◽  
Vol 75 (3) ◽  
pp. 74-84 ◽  
Author(s):  
A.E. Abaturov ◽  
◽  
E.A. Agafonova ◽  
N.I. Abaturova ◽  
V.L. Babich ◽  
...  

2021 ◽  
Vol 8 (8) ◽  
pp. 2004979
Author(s):  
Jun‐Young Park ◽  
Sung Jean Park ◽  
Jun Young Park ◽  
Sang‐Hyun Kim ◽  
Song Kwon ◽  
...  

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