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Kim ET, Kim YS, Park SJ. Genomic sequence of the non-pathogen Neisseria sp. strain MA1-1 with antibiotic resistance and virulence factors isolated from a head and neck cancer patient. Arch Microbiol 2022; 204:591. [PMID: 36053331 DOI: 10.1007/s00203-022-03212-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 08/22/2022] [Indexed: 11/29/2022]
Abstract
Recent research has claimed virulence factors or antimicrobial resistance in commensal or non-pathogenic Neisseria spp. This study aimed to isolate and analyze commensal microorganisms related to the genus Neisseria from the oral cavity of a patient with head and neck cancer. We successfully isolated strain MA1-1 and identified its functional gene contents. Although strain MA1-1 was related to Neisseria flava based on 16S rRNA gene sequence similarity, genomic relatedness analysis revealed that strain MA1-1 was closely related to Neisseria mucosa, reported as a commensal Neisseria species. The strain MA1-1 genome harbored genes for microaerobic respiration and the complete core metabolic pathway with few transporters for nutrients. A number of genes have been associated with virulence factors and resistance to various antibiotics. In addition, the comparative genomic analysis showed that most genes identified in the strain MA1-1 were shared with other Neisseria spp. including two well-known pathogens, Neisseria gonorrhoeae and Neisseria meningitidis. This indicates that the gene content of intra-members of the genus Neisseria has been evolutionarily conserved and is stable, with no gene recombination with other microbes in the host. Finally, this study provides more fundamental interpretations for the complete gene sequence of commensal Neisseria spp. and will contribute to advancing public health knowledge.
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Affiliation(s)
- Eui Tae Kim
- Department of Microbiology and Immunology, Jeju National University College of Medicine, Aran 13-15, Jeju, 63241, Republic of Korea
| | - Young Suk Kim
- Department of Radiation Oncology, Jeju National University College of Medicine, Jeju National University Hospital, Aran 13-15, Jeju, 63241, Republic of Korea
| | - Soo-Je Park
- Department of Biology, Jeju National University, 102 Jejudaehak-ro, Jeju, 63243, Republic of Korea.
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2
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Nyongesa S, Chenal M, Bernet È, Coudray F, Veyrier FJ. Sequential markerless genetic manipulations of species from the Neisseria genus. Can J Microbiol 2022; 68:551-560. [PMID: 35512370 DOI: 10.1139/cjm-2022-0024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The development of simple and highly efficient strategies for genetic modifications are essential for post-genetic studies aimed at characterizing gene functions for various applications. We sought to develop a reliable system for Neisseria species that allows for both unmarked and accumulation of multiple genetic modifications in a single strain. In this work we developed and validated three-gene cassettes named RPLK and RPCC, comprising of an antibiotic resistance marker for positive selection, the phenotypic selection marker lacZ or mCherry, and the counter selection gene rpsL. These cassettes can be transformed with high efficiency across the Neisseria genus while significantly reducing the number of false positives compared to similar approaches. We exemplify the versatility and application of these systems by obtaining unmarked luminescent strains (knock-in) or mutants (knock-out) in different pathogenic and commensal species across the Neisseria genus in addition to the cumulative deletion of six loci in a single strain of Neisseria elongata.
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Affiliation(s)
- Sammy Nyongesa
- INRS, 14851, Centre Armand-Frappier Santé Biotechnologie, Quebec, Quebec, Canada;
| | - Martin Chenal
- INRS, 14851, Centre Armand-Frappier Santé Biotechnologie, Quebec, Quebec, Canada;
| | - Ève Bernet
- INRS, 14851, Centre Armand-Frappier Santé Biotechnologie, Quebec, Quebec, Canada;
| | - Florian Coudray
- INRS, 14851, Centre Armand-Frappier Santé Biotechnologie, Quebec, Quebec, Canada;
| | - Frédéric J Veyrier
- INRS, 14851, Centre Armand-Frappier Santé Biotechnologie, Quebec, Quebec, Canada;
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3
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Abstract
The genus Neisseria includes two pathogenic species, N. gonorrhoeae and N. meningitidis, and numerous commensal species. Neisseria species frequently exchange DNA with one another, primarily via transformation and homologous recombination and via multiple types of mobile genetic elements (MGEs). Few Neisseria bacteriophages (phages) have been identified, and their impact on bacterial physiology is poorly understood. Furthermore, little is known about the range of species that Neisseria phages can infect. In this study, we used three virus prediction tools to scan 248 genomes of 21 different Neisseria species and identified 1,302 unique predicted prophages. Using comparative genomics, we found that many predictions are dissimilar from prophages and other MGEs previously described to infect Neisseria species. We also identified similar predicted prophages in genomes of different Neisseria species. Additionally, we examined CRISPR-Cas targeting of each Neisseria genome and predicted prophage. While CRISPR targeting of chromosomal DNA appears to be common among several Neisseria species, we found that 20% of the prophages we predicted are targeted significantly more than the rest of the bacterial genome in which they were identified (i.e., backbone). Furthermore, many predicted prophages are targeted by CRISPR spacers encoded by other species. We then used these results to infer additional host species of known Neisseria prophages and predictions that are highly targeted relative to the backbone. Together, our results suggest that we have identified novel Neisseria prophages, several of which may infect multiple Neisseria species. These findings have important implications for understanding horizontal gene transfer between members of this genus. IMPORTANCE Drug-resistant Neisseria gonorrhoeae is a major threat to human health. Commensal Neisseria species are thought to serve as reservoirs of antibiotic resistance and virulence genes for the pathogenic species N. gonorrhoeae and N. meningitidis. Therefore, it is important to understand both the diversity of mobile genetic elements (MGEs) that can mediate horizontal gene transfer within this genus and the breadth of species these MGEs can infect. In particular, few bacteriophages (phages) are known to infect Neisseria species. In this study, we identified a large number of candidate phages integrated in the genomes of commensal and pathogenic Neisseria species, many of which appear to be novel phages. Importantly, we discovered extensive interspecies targeting of predicted phages by Neisseria CRISPR-Cas systems, which may reflect their movement between different species. Uncovering the diversity and host range of phages is essential for understanding how they influence the evolution of their microbial hosts.
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CRISPR/Cas Technology in Pig-to-Human Xenotransplantation Research. Int J Mol Sci 2021; 22:ijms22063196. [PMID: 33801123 PMCID: PMC8004187 DOI: 10.3390/ijms22063196] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023] Open
Abstract
CRISPR/Cas (clustered regularly interspaced short palindromic repeats linked to Cas nuclease) technology has revolutionized many aspects of genetic engineering research. Thanks to it, it became possible to study the functions and mechanisms of biology with greater precision, as well as to obtain genetically modified organisms, both prokaryotic and eukaryotic. The changes introduced by the CRISPR/Cas system are based on the repair paths of the single or double strand DNA breaks that cause insertions, deletions, or precise integrations of donor DNA. These changes are crucial for many fields of science, one of which is the use of animals (pigs) as a reservoir of tissues and organs for xenotransplantation into humans. Non-genetically modified animals cannot be used to save human life and health due to acute immunological reactions resulting from the phylogenetic distance of these two species. This review is intended to collect and summarize the advantages as well as achievements of the CRISPR/Cas system in pig-to-human xenotransplantation research. In addition, it demonstrates barriers and limitations that require careful evaluation before attempting to experiment with this technology.
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Calder A, Menkiti CJ, Çağdaş A, Lisboa Santos J, Streich R, Wong A, Avini AH, Bojang E, Yogamanoharan K, Sivanesan N, Ali B, Ashrafi M, Issa A, Kaur T, Latif A, Mohamed HAS, Maqsood A, Tamang L, Swager E, Stringer AJ, Snyder LAS. Virulence genes and previously unexplored gene clusters in four commensal Neisseria spp. isolated from the human throat expand the neisserial gene repertoire. Microb Genom 2020; 6. [PMID: 32845827 PMCID: PMC7643975 DOI: 10.1099/mgen.0.000423] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Commensal non-pathogenic Neisseria spp. live within the human host alongside the pathogenic Neisseria meningitidis and Neisseria gonorrhoeae and due to natural competence, horizontal gene transfer within the genus is possible and has been observed. Four distinct Neisseria spp. isolates taken from the throats of two human volunteers have been assessed here using a combination of microbiological and bioinformatics techniques. Three of the isolates have been identified as Neisseria subflava biovar perflava and one as Neisseria cinerea. Specific gene clusters have been identified within these commensal isolate genome sequences that are believed to encode a Type VI Secretion System, a newly identified CRISPR system, a Type IV Secretion System unlike that in other Neisseria spp., a hemin transporter, and a haem acquisition and utilization system. This investigation is the first to investigate these systems in either the non-pathogenic or pathogenic Neisseria spp. In addition, the N. subflava biovar perflava possess previously unreported capsule loci and sequences have been identified in all four isolates that are similar to genes seen within the pathogens that are associated with virulence. These data from the four commensal isolates provide further evidence for a Neisseria spp. gene pool and highlight the presence of systems within the commensals with functions still to be explored.
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Affiliation(s)
- Alan Calder
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Chukwuma Jude Menkiti
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Aylin Çağdaş
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Jefferson Lisboa Santos
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Ricarda Streich
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Alice Wong
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Amir H Avini
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Ebrima Bojang
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Karththeepan Yogamanoharan
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Nivetha Sivanesan
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Besma Ali
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Mariam Ashrafi
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Abdirizak Issa
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Tajinder Kaur
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Aisha Latif
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Hani A Sheik Mohamed
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Atifa Maqsood
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Laxmi Tamang
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Emily Swager
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Alex J Stringer
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
| | - Lori A S Snyder
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Kingston upon Thames, KT1 2EE, UK
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6
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Davidson AR, Lu WT, Stanley SY, Wang J, Mejdani M, Trost CN, Hicks BT, Lee J, Sontheimer EJ. Anti-CRISPRs: Protein Inhibitors of CRISPR-Cas Systems. Annu Rev Biochem 2020; 89:309-332. [PMID: 32186918 PMCID: PMC9718424 DOI: 10.1146/annurev-biochem-011420-111224] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) together with their accompanying cas (CRISPR-associated) genes are found frequently in bacteria and archaea, serving to defend against invading foreign DNA, such as viral genomes. CRISPR-Cas systems provide a uniquely powerful defense because they can adapt to newly encountered genomes. The adaptive ability of these systems has been exploited, leading to their development as highly effective tools for genome editing. The widespread use of CRISPR-Cas systems has driven a need for methods to control their activity. This review focuses on anti-CRISPRs (Acrs), proteins produced by viruses and other mobile genetic elements that can potently inhibit CRISPR-Cas systems. Discovered in 2013, there are now 54 distinct families of these proteins described, and the functional mechanisms of more than a dozen have been characterized in molecular detail. The investigation of Acrs is leading to a variety of practical applications and is providing exciting new insight into the biology of CRISPR-Cas systems.
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Affiliation(s)
- Alan R Davidson
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada; , , ,
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1M1, Canada; , ,
| | - Wang-Ting Lu
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1M1, Canada; , ,
| | - Sabrina Y Stanley
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada; , , ,
| | - Jingrui Wang
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada; , , ,
| | - Marios Mejdani
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1M1, Canada; , ,
| | - Chantel N Trost
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada; , , ,
| | - Brian T Hicks
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1M1, Canada; , ,
| | - Jooyoung Lee
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA; ,
| | - Erik J Sontheimer
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA; ,
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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7
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Amrani N, Gao XD, Liu P, Edraki A, Mir A, Ibraheim R, Gupta A, Sasaki KE, Wu T, Donohoue PD, Settle AH, Lied AM, McGovern K, Fuller CK, Cameron P, Fazzio TG, Zhu LJ, Wolfe SA, Sontheimer EJ. NmeCas9 is an intrinsically high-fidelity genome-editing platform. Genome Biol 2018; 19:214. [PMID: 30518407 PMCID: PMC6282386 DOI: 10.1186/s13059-018-1591-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 11/17/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND The development of CRISPR genome editing has transformed biomedical research. Most applications reported thus far rely upon the Cas9 protein from Streptococcus pyogenes SF370 (SpyCas9). With many RNA guides, wildtype SpyCas9 can induce significant levels of unintended mutations at near-cognate sites, necessitating substantial efforts toward the development of strategies to minimize off-target activity. Although the genome-editing potential of thousands of other Cas9 orthologs remains largely untapped, it is not known how many will require similarly extensive engineering to achieve single-site accuracy within large genomes. In addition to its off-targeting propensity, SpyCas9 is encoded by a relatively large open reading frame, limiting its utility in applications that require size-restricted delivery strategies such as adeno-associated virus vectors. In contrast, some genome-editing-validated Cas9 orthologs are considerably smaller and therefore better suited for viral delivery. RESULTS Here we show that wildtype NmeCas9, when programmed with guide sequences of the natural length of 24 nucleotides, exhibits a nearly complete absence of unintended editing in human cells, even when targeting sites that are prone to off-target activity with wildtype SpyCas9. We also validate at least six variant protospacer adjacent motifs (PAMs), in addition to the preferred consensus PAM (5'-N4GATT-3'), for NmeCas9 genome editing in human cells. CONCLUSIONS Our results show that NmeCas9 is a naturally high-fidelity genome-editing enzyme and suggest that additional Cas9 orthologs may prove to exhibit similarly high accuracy, even without extensive engineering.
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Affiliation(s)
- Nadia Amrani
- RNA Therapeutics Institute, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Xin D Gao
- RNA Therapeutics Institute, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Pengpeng Liu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Alireza Edraki
- RNA Therapeutics Institute, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Aamir Mir
- RNA Therapeutics Institute, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Raed Ibraheim
- RNA Therapeutics Institute, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Ankit Gupta
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
- Present Address: Bluebird bio, Cambridge, MA, USA
| | - Kanae E Sasaki
- RNA Therapeutics Institute, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
- Present Address: Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, MA, USA
| | - Tong Wu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Paul D Donohoue
- Caribou Biosciences, Inc., 2929 7th Street, Suite 105, Berkeley, CA, 94710, USA
| | - Alexander H Settle
- Caribou Biosciences, Inc., 2929 7th Street, Suite 105, Berkeley, CA, 94710, USA
- Present Address: Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Alexandra M Lied
- Caribou Biosciences, Inc., 2929 7th Street, Suite 105, Berkeley, CA, 94710, USA
| | - Kyle McGovern
- Caribou Biosciences, Inc., 2929 7th Street, Suite 105, Berkeley, CA, 94710, USA
- Present Address: Sangamo Therapeutics, Inc., Richmond, CA, USA
| | - Chris K Fuller
- Caribou Biosciences, Inc., 2929 7th Street, Suite 105, Berkeley, CA, 94710, USA
| | - Peter Cameron
- Caribou Biosciences, Inc., 2929 7th Street, Suite 105, Berkeley, CA, 94710, USA
| | - Thomas G Fazzio
- Program in Molecular Medicine, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Lihua Julie Zhu
- Program in Molecular Medicine, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Scot A Wolfe
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Erik J Sontheimer
- RNA Therapeutics Institute, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA.
- Program in Molecular Medicine, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA.
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Abstract
Genome editing technologies have been revolutionized by the discovery of prokaryotic RNA-guided defense system called CRISPR-Cas. Cas9, a single effector protein found in type II CRISPR systems, has been at the heart of this genome editing revolution. Nearly half of the Cas9s discovered so far belong to the type II-C subtype but have not been explored extensively. Type II-C CRISPR-Cas systems are the simplest of the type II systems, employing only three Cas proteins. Cas9s are central players in type II-C systems since they function in multiple steps of the CRISPR pathway, including adaptation and interference. Type II-C CRISPR systems are found in bacteria and archaea from very diverse environments, resulting in Cas9s with unique and potentially useful properties. Certain type II-C Cas9s possess unusually long PAMs, function in unique conditions (e.g., elevated temperature), and tend to be smaller in size. Here, we review the biology, mechanism, and applications of the type II-C CRISPR systems with particular emphasis on their Cas9s.
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Affiliation(s)
- Aamir Mir
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, U.S.A
| | - Alireza Edraki
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, U.S.A
| | - Jooyoung Lee
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, U.S.A
| | - Erik J. Sontheimer
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, U.S.A
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, U.S.A
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9
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Programmable RNA Cleavage and Recognition by a Natural CRISPR-Cas9 System from Neisseria meningitidis. Mol Cell 2018; 69:906-914.e4. [PMID: 29456189 DOI: 10.1016/j.molcel.2018.01.025] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 12/18/2017] [Accepted: 01/18/2018] [Indexed: 12/26/2022]
Abstract
The microbial CRISPR systems enable adaptive defense against mobile elements and also provide formidable tools for genome engineering. The Cas9 proteins are type II CRISPR-associated, RNA-guided DNA endonucleases that identify double-stranded DNA targets by sequence complementarity and protospacer adjacent motif (PAM) recognition. Here we report that the type II-C CRISPR-Cas9 from Neisseria meningitidis (Nme) is capable of programmable, RNA-guided, site-specific cleavage and recognition of single-stranded RNA targets and that this ribonuclease activity is independent of the PAM sequence. We define the mechanistic feature and specificity constraint for RNA cleavage by NmeCas9 and also show that nuclease null dNmeCas9 binds to RNA target complementary to CRISPR RNA. Finally, we demonstrate that NmeCas9-catalyzed RNA cleavage can be blocked by three families of type II-C anti-CRISPR proteins. These results fundamentally expand the targeting capacities of CRISPR-Cas9 and highlight the potential utility of NmeCas9 as a single platform to target both RNA and DNA.
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