SnapShot: Class 2 CRISPR-Cas Systems

Makarova, Kira S.; Zhang, Feng; Koonin, Eugene V.

doi:10.1016/j.cell.2016.12.038

Cited by 152 publications

(129 citation statements)

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“…Specifically, subtype II‐A systems include an additional gene, csn2 which is considered a signature gene for this subtype (Makarova et al . , ). Very interestingly, the comparative analysis between all the Cas3 signature protein sequences revealed an almost complete amino acid identity between the Cas3 proteins related to the same CRISPR repeat family, regardless of the CRISPR‐Cas subtype of belonging (Fig.…”

Section: Resultsmentioning

confidence: 99%

Survey on the CRISPR arrays in Lactobacillus helveticus genomes

Scaltriti¹,

Carminati²,

Cortimiglia

et al. 2019

Lett Appl Microbiol

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Lactobacillus helveticus is a homofermentative thermophilic lactic acid bacteria that is mainly used in the manufacture of Swiss type and long‐ripened Italian hard cheeses. In this study, the presence of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) were analysed in 25 L. helveticus genomes and identified in 23 of these genomes. A total of 40 CRISPR loci were identified and classified into five main families based on CRISPR repeats: Ldbu1, Lsal1, Lhel1, Lhel2 and a new repeat family named Lhel3. Spacers had a size between 30 and 40 bp whereas repeats have an average size of 30 bp, with three longer repeats. The analysis displayed the presence of conserved spacers in 23 of the 40 CRISPR loci. A geographical distribution of L. helveticus isolates with similar CRISPR spacer array profiles were not observed. Based on the presence of the signature protein Cas3, all CRISPR loci belonged to Type I. This analysis demonstrated a great CRISPR array variability within L. helveticus, which could be a useful tool for genotypic strain differentiation. A next step will be to understand the possible role of CRISPR/Cas system for the resistance of L. helveticus to phage infection. Significance and Impact of the Study Lactobacillus helveticus, a lactic acid bacteria species widely used as starter culture in the dairy industry has recently also gained importance as health‐promoting culture in probiotic and nutraceutical food products. The CRISPR/Cas system, a well‐known molecular mechanism that provides adaptive immunity against exogenous genetic elements such as bacteriophages and plasmids in bacteria, was recently found in this species. In this study, we investigated the presence and genetic heterogeneity of CRISPR loci in 25 L. helveticus genomes. The results presented here represent an important step on the way to manage phage resistance, plasmid uptake and genome editing in this species.

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Section: Resultsmentioning

confidence: 99%

Survey on the CRISPR arrays in Lactobacillus helveticus genomes

Scaltriti¹,

Carminati²,

Cortimiglia

et al. 2019

Lett Appl Microbiol

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“…The bacteria can protect themselves using a series of CRISPR associated (Cas) proteins that cleave viral DNA, insert pieces of viral DNA into their own genomes, and then use certain Cas9 protein(s) paired with RNA transcribed from the viral DNA library to make targeted double-strand breaks in invading viral DNA. Class 2 CRISPR-Cas systems utilize single-protein effectors, such as Cas9, for DNA targeting [37]. Cas9 is composed of two endonuclease domains, HNH and a RuvC-like domain that each cut one strand of DNA (Fig.…”

Section: Rapid Evolution Of Sequence Specific Nucleases (Ssns) For Plmentioning

confidence: 99%

Plant genome editing with TALEN and CRISPR

2017

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Genome editing promises giant leaps forward in advancing biotechnology, agriculture, and basic research. The process relies on the use of sequence specific nucleases (SSNs) to make DNA double stranded breaks at user defined genomic loci, which are subsequently repaired by two main DNA repair pathways: non-homologous end joining (NHEJ) and homology directed repair (HDR). NHEJ can result in frameshift mutations that often create genetic knockouts. These knockout lines are useful for functional and reverse genetic studies but also have applications in agriculture. HDR has a variety of applications as it can be used for gene replacement, gene stacking, and for creating various fusion proteins. In recent years, transcription activator-like effector nucleases and clustered regularly interspaced palindromic repeats (CRISPR) and CRISPR associated protein 9 or CRISPR from Prevotella and Francisella 1 have emerged as the preferred SSNs for research purposes. Here, we review their applications in plant research, discuss current limitations, and predict future research directions in plant genome editing.

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“…Spacers are actually exogenous DNA fragments processed by Cas proteins and embedded into CRISPR loci as templates for CRISPR RNA (crRNA) transcription, which acts as a genetic memory and further mediates specific recognition of invading DNA [Brouns et al, ]. cas genes are responsible for coding multiple functional proteins participating in biogenesis process, effector complexes organization, adaptation and adherence to foreign sequences, and RNA or DNA cleavage [Makarova et al, ,]. As the understanding of CRISPR‐Cas systems was deepened, systems from different organisms were roughly divided into two classes: Class 1 systems utilizing multi‐protein effector complexes, and Class 2 systems utilizing single‐protein effector complexes.…”

Section: Improved Understanding Of Crispr‐cas Systemsmentioning

confidence: 99%

Progress and Application of CRISPR/Cas Technology in Biological and Biomedical Investigation

Lin

Zhou

Liu

et al. 2017

J of Cellular Biochemistry

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Based on the tremendous progress of the understanding on the CRISPR-Cas systems, the application CRISPR/Cas technology has been extended into increasing scenarios in biological and biomedical investigation. The potency of gene editing has been greatly improved by the rapid development of engineered Cas9 variants and modified CRISPR platforms. As advanced sequencing technology identified vast causative genetic basis for human diseases, CRISPR toolkits are now able to mediate precise genetic disruption or correction in vitro and in vivo. In this review, we have discussed the recent development of the CRISPR/Cas gene-editing technology and the extensive applications of the CRISPR platforms in biological and biomedical investigation, including disease modeling in animal and human cell line, development of gene therapy, as well as high-throughput genetic screening. J. Cell. Biochem. 118: 3061-3071, 2017. © 2017 Wiley Periodicals, Inc.

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SnapShot: Class 2 CRISPR-Cas Systems

Cited by 152 publications

References 0 publications

Survey on the CRISPR arrays in Lactobacillus helveticus genomes

Survey on the CRISPR arrays in Lactobacillus helveticus genomes

Plant genome editing with TALEN and CRISPR

Progress and Application of CRISPR/Cas Technology in Biological and Biomedical Investigation

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