scholarly journals DNA targeting by Clostridium cellulolyticum CRISPR–Cas9 Type II-C system

2020 ◽  
Vol 48 (4) ◽  
pp. 2026-2034 ◽  
Author(s):  
Iana Fedorova ◽  
Anatolii Arseniev ◽  
Polina Selkova ◽  
Georgii Pobegalov ◽  
Ignatiy Goryanin ◽  
...  
Keyword(s):  
Genome Editing ◽  
Streptococcus Pyogenes ◽  
Genome Engineering ◽  
Bacterial Species ◽  
Type Ii ◽  
Biotechnological Applications ◽  
Clostridium Cellulolyticum ◽  
Dna Targeting ◽  
Biochemical Diversity

Abstract Type II CRISPR–Cas9 RNA-guided nucleases are widely used for genome engineering. Type II-A SpCas9 protein from Streptococcus pyogenes is the most investigated and highly used enzyme of its class. Nevertheless, it has some drawbacks, including a relatively big size, imperfect specificity and restriction to DNA targets flanked by an NGG PAM sequence. Cas9 orthologs from other bacterial species may provide a rich and largely untapped source of biochemical diversity, which can help to overcome the limitations of SpCas9. Here, we characterize CcCas9, a Type II-C CRISPR nuclease from Clostridium cellulolyticum H10. We show that CcCas9 is an active endonuclease of comparatively small size that recognizes a novel two-nucleotide PAM sequence. The CcCas9 can potentially broaden the existing scope of biotechnological applications of Cas9 nucleases and may be particularly advantageous for genome editing of C. cellulolyticum H10, a bacterium considered to be a promising biofuel producer.

scholarly journals Phylogeny of Cas9 determines functional exchangeability of dual-RNA and Cas9 among orthologous type II CRISPR-Cas systems

2013 ◽  
Vol 42 (4) ◽  
pp. 2577-2590 ◽  
Author(s):  
Ines Fonfara ◽  
Anaïs Le Rhun ◽  
Krzysztof Chylinski ◽  
Kira S. Makarova ◽  
Anne-Laure Lécrivain ◽  
...  
Keyword(s):  
Genome Editing ◽  
Horizontal Transfer ◽  
Genome Engineering ◽  
Bacterial Species ◽  
Type Ii ◽  
Promising Technology ◽  
Dna Targeting ◽  
Protospacer Adjacent Motif ◽  
Cas9 Protein ◽  
Specific Manner

Abstract The CRISPR-Cas-derived RNA-guided Cas9 endonuclease is the key element of an emerging promising technology for genome engineering in a broad range of cells and organisms. The DNA-targeting mechanism of the type II CRISPR-Cas system involves maturation of tracrRNA:crRNA duplex (dual-RNA), which directs Cas9 to cleave invading DNA in a sequence-specific manner, dependent on the presence of a Protospacer Adjacent Motif (PAM) on the target. We show that evolution of dual-RNA and Cas9 in bacteria produced remarkable sequence diversity. We selected eight representatives of phylogenetically defined type II CRISPR-Cas groups to analyze possible coevolution of Cas9 and dual-RNA. We demonstrate that these two components are interchangeable only between closely related type II systems when the PAM sequence is adjusted to the investigated Cas9 protein. Comparison of the taxonomy of bacterial species that harbor type II CRISPR-Cas systems with the Cas9 phylogeny corroborates horizontal transfer of the CRISPR-Cas loci. The reported collection of dual-RNA:Cas9 with associated PAMs expands the possibilities for multiplex genome editing and could provide means to improve the specificity of the RNA-programmable Cas9 tool.

scholarly journals Orthogonal CRISPR-Cas genome editing and efficient inhibition with anti-CRISPRs in zebrafish embryos

2020 ◽  
Author(s):  
Paige R. Takasugi ◽  
Evan P. Drage ◽  
Sahar N. Kanishka ◽  
Marissa A. Higbee ◽  
James A. Gagnon
Keyword(s):  
Genome Editing ◽  
Streptococcus Pyogenes ◽  
High Efficiency ◽  
Bacterial Species ◽  
Zebrafish Embryos ◽  
Type Ii ◽  
Guide Rnas ◽  
Highly Effective ◽  
Orthogonal Systems ◽  
Spatiotemporal Control

AbstractThe CRISPR-Cas universe continues to expand. The type II CRISPR-Cas system from Streptococcus pyogenes (SpCas9) is most widely used for genome editing due to its high efficiency in cells and organisms. However, concentrating on a single CRISPR-Cas system limits options for multiplexed editing. We hypothesized that CRISPR-Cas systems originating from different bacterial species could operate simultaneously and independently due to their distinct single-guide RNAs (sgRNAs) or CRISPR-RNAs (crRNAs), and protospacer adjacent motifs (PAMs). Additionally, we hypothesized that CRISPR-Cas activity in zebrafish could be regulated through the expression of inhibitory anti-CRISPR (Acr) proteins. Here, we use a simple mutagenesis approach to demonstrate that CRISPR-Cas systems from Streptococcus pyogenes (SpCas9), Streptococcus aureus (SaCas9), and Lachnospiraceae bacterium (LbCas12a, previously known as LbCpf1) are highly effective, orthogonal systems capable of operating simultaneously in zebrafish. We also demonstrate that type II Acrs are effective inhibitors of SpCas9 in zebrafish. These results indicate that at least three orthogonal CRISPR-Cas systems and two anti-CRISPR proteins are functional in zebrafish embryos. These CRISPR-Cas systems and Acr proteins will enable combinatorial and intersectional strategies for spatiotemporal control of genome editing in zebrafish.

scholarly journals Genome Engineering in Plant Using an Efficient CRISPR-xCas9 Toolset With an Expanded PAM Compatibility

2020 ◽  
Vol 2 ◽  
Author(s):  
Chengwei Zhang ◽  
Guiting Kang ◽  
Xinxiang Liu ◽  
Si Zhao ◽  
Shuang Yuan ◽  
...  
Keyword(s):  
Genome Editing ◽  
Plant Species ◽  
Streptococcus Pyogenes ◽  
Genome Engineering ◽  
Human Cells ◽  
Rice Plants ◽  
Potential Target ◽  
Protospacer Adjacent Motif ◽  
Target Sites ◽  
Related Plant

The CRISPR-Cas9 system enables simple, rapid, and effective genome editing in many species. Nevertheless, the requirement of an NGG protospacer adjacent motif (PAM) for the widely used canonical Streptococcus pyogenes Cas9 (SpCas9) limits the potential target sites. The xCas9, an engineered SpCas9 variant, was developed to broaden the PAM compatibility to NG, GAA, and GAT PAMs in human cells. However, no knockout rice plants were generated for GAA PAM sites, and only one edited target with a GAT PAM was reported. In this study, we used tRNA and enhanced sgRNA (esgRNA) to develop an efficient CRISPR-xCas9 genome editing system able to mutate genes at NG, GAA, GAT, and even GAG PAM sites in rice. We also developed the corresponding xCas9-based cytosine base editor (CBE) that can edit the NG and GA PAM sites. These new editing tools will be useful for future rice research or breeding, and may also be applicable for other related plant species.

scholarly journals CRISPR/Cas12a mediated genome engineering in photosynthetic bacteria

2020 ◽  
Author(s):  
Yang Zhang ◽  
Jifeng Yuan
Keyword(s):  
Genome Editing ◽  
Transcriptional Repression ◽  
Gene Editing ◽  
Photosynthetic Bacteria ◽  
Genome Engineering ◽  
Biotechnological Applications ◽  
End Joining ◽  
Editing Efficiency ◽  
Francisella Novicida ◽  
Non Homologous End Joining

ABSTRACTPurple non-sulfur photosynthetic bacteria (PNSB) such as R. capsulatus serve as a versatile platform for fundamental studies and various biotechnological applications. In this study, we sought to develop the class II RNA-guided CRISPR/Cas12a system from Francisella novicida for both genome editing and gene down-regulation in R. capsulatus. About 90% editing efficiency was achieved by using CRISPR/Cas12a driven by a strong promoter Ppuc when targeting ccoO or nifH gene. When both genes were simultaneously targeted, the multiplex gene editing efficiency reached >63%. In addition, CRISPR interference using deactivated Cas12a was also evaluated using reporter genes gfp and lacZ, and the repression efficiency reached >80%. In summary, our work represents the first report to develop CRISPR/Cas12a mediated genome editing/transcriptional repression in R. capsulatus, which would greatly accelerate PNSB-related researches.IMPORTANCEPurple non-sulfur photosynthetic bacteria (PNSB) such as R. capsulatus serve as a versatile platform for fundamental studies and various biotechnological applications. However, lack of efficient gene editing tools remains a main obstacle for progressing in PNSB-related researches. Here, we developed CRISPR/Cas12a for genome editing via the non-homologous end joining (NHEJ) repair machinery in R. capsulatus. In addition, DNase-deactivated Cas12a was found to simultaneously suppress multiple targeted genes. Taken together, our work offers a new set of tools for efficient genome engineering in PNSB such as R. capsulatus.

scholarly journals Reprogrammed tracrRNAs enable repurposing RNAs as crRNAs and detecting RNAs

2021 ◽  
Author(s):  
Yang Liu ◽  
Filipe Pinto ◽  
Xinyi Wan ◽  
Shuguang Peng ◽  
Mengxi Li ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Transcriptional Activity ◽  
Host Genome ◽  
Type Ii ◽  
Guide Rna ◽  
Dna Targeting ◽  
Cellular Computing ◽  
Rna Sensors

In type II CRISPR systems, the guide RNA (gRNA) consists of a CRISPR RNA (crRNA) and a hybridized trans-acting CRISPR RNA (tracrRNA) which interacts directly with Cas9 and is essential to its guided DNA targeting function. Though tracrRNAs are diverse in sequences and structures across type II CRISPR systems, the programmability of crRNA-tracrRNA hybridization for particular Cas9 has not been studied adequately. Here, we revealed the high programmability of crRNA-tracrRNA hybridization for Streptococcus pyogenes Cas9. By reprogramming the crRNA-tracrRNA hybridized sequence, reprogrammed tracrRNAs can repurpose various RNAs as crRNAs to trigger CRISPR function. We showed that the engineered crRNA-tracrRNA pairs enable design of orthogonal cellular computing devices and hijacking of endogenous RNAs as crRNAs. We next designed novel RNA sensors that can monitor the transcriptional activity of specific genes on the host genome and detect SARS-CoV-2 RNA in vitro. The engineering potential of crRNA-tracrRNA interaction has therefore redefined the capabilities of CRISPR/Cas9 system.

scholarly journals UPGMA - analysis of type II CRISPR RNA-guided endonuclease Cas9 homologues from the compost metagenome

2021 ◽  
Vol 265 ◽  
pp. 04010
Author(s):  
Andrei A. Zimin ◽  
Alexandra N. Karmanova ◽  
Yinhua Lu
Keyword(s):  
Genetic Diversity ◽  
Genome Editing ◽  
Structural Modeling ◽  
Type Ii ◽  
Biotechnological Applications ◽  
Catalytic Processes

Metagenomic approaches provide access to the genetic diversity of the environment for biotechnological applications, allowing the discovery of new enzymes and new pathways for numerous catalytic processes. Five new putative type II CRISPR-Cas9 DNA endonucleases were identified from the compost community using the DELTA-BLAST algorithm. It was determined using phylogenetic UPGMA analysis that four of these potential enzymes are similar to those of the Bacteroidetes. Protein structural modeling confirmed the data of DELTA-BLAST and UPGMA analysis. These new five proteins found may be promising for genome editing in termoresistant Actinomyces.

scholarly journals Inducible Plasmid Self-Destruction (IPSD) assisted genome engineering in lactobacilli and bifidobacteria

2019 ◽  
Author(s):  
Fanglei Zuo ◽  
Zhu Zeng ◽  
Lennart Hammarström ◽  
Harold Marcotte
Keyword(s):  
Synthetic Biology ◽  
Homologous Recombination ◽  
Genetic Engineering ◽  
Genome Editing ◽  
Genome Engineering ◽  
Bacterial Species ◽  
Knock Out ◽  
Recombination System ◽  
A Genome ◽  
Selection Of

ABSTRACTGenome engineering is essential for application of synthetic biology in probiotics including lactobacilli and bifidobacteria. Several homologous recombination system-based mutagenesis tools have been developed for these bacteria but still, have many limitations in different species or strains. Here we developed a genome engineering method based on an inducible self-destruction plasmid delivering homologous DNA into bacteria. Excision of the replicon by induced recombinase facilitates selection of homologous recombination events. This new genome editing tool called Inducible Plasmid Self-Destruction (IPSD) was successfully used to perform gene knock-out and knock-in in lactobacilli and bifidobacteria. Due to its simplicity and universality, the IPSD strategy may provide a general approach for genetic engineering of various bacterial species.

scholarly journals A catalogue of biochemically diverse CRISPR-Cas9 orthologs

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Giedrius Gasiunas ◽  
Joshua K. Young ◽  
Tautvydas Karvelis ◽  
Darius Kazlauskas ◽  
Tomas Urbaitis ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Genome Editing ◽  
Type Ii ◽  
Single Nucleotide ◽  
Guide Rna ◽  
Protospacer Adjacent Motif ◽  
Biochemical Analyses ◽  
Sequence Requirements ◽  
Biochemical Diversity

Abstract Bacterial Cas9 nucleases from type II CRISPR-Cas antiviral defence systems have been repurposed as genome editing tools. Although these proteins are found in many microbes, only a handful of variants are used for these applications. Here, we use bioinformatic and biochemical analyses to explore this largely uncharacterized diversity. We apply cell-free biochemical screens to assess the protospacer adjacent motif (PAM) and guide RNA (gRNA) requirements of 79 Cas9 proteins, thus identifying at least 7 distinct gRNA classes and 50 different PAM sequence requirements. PAM recognition spans the entire spectrum of T-, A-, C-, and G-rich nucleotides, from single nucleotide recognition to sequence strings longer than 4 nucleotides. Characterization of a subset of Cas9 orthologs using purified components reveals additional biochemical diversity, including both narrow and broad ranges of temperature dependence, staggered-end DNA target cleavage, and a requirement for long stretches of homology between gRNA and DNA target. Our results expand the available toolset of RNA-programmable CRISPR-associated nucleases.

scholarly journals Characterization and repurposing of the endogenous Type I-F CRISPR–Cas system of Zymomonas mobilis for genome engineering

2019 ◽  
Vol 47 (21) ◽  
pp. 11461-11475 ◽  
Author(s):  
Yanli Zheng ◽  
Jiamei Han ◽  
Baiyang Wang ◽  
Xiaoyun Hu ◽  
Runxia Li ◽  
...  
Keyword(s):  
Genome Editing ◽  
Zymomonas Mobilis ◽  
Genome Engineering ◽  
Functional Characterization ◽  
Type I ◽  
Dna Targeting ◽  
Engineering Practices ◽  
Restriction Modification ◽  
Shed Light

Abstract Application of CRISPR-based technologies in non-model microorganisms is currently very limited. Here, we reported efficient genome engineering of an important industrial microorganism, Zymomonas mobilis, by repurposing the endogenous Type I-F CRISPR–Cas system upon its functional characterization. This toolkit included a series of genome engineering plasmids, each carrying an artificial self-targeting CRISPR and a donor DNA for the recovery of recombinants. Through this toolkit, various genome engineering purposes were efficiently achieved, including knockout of ZMO0038 (100% efficiency), cas2/3 (100%), and a genomic fragment of >10 kb (50%), replacement of cas2/3 with mCherry gene (100%), in situ nucleotide substitution (100%) and His-tagging of ZMO0038 (100%), and multiplex gene deletion (18.75%) upon optimal donor size determination. Additionally, the Type I-F system was further applied for CRISPRi upon Cas2/3 depletion, which has been demonstrated to successfully silence the chromosomally integrated mCherry gene with its fluorescence intensity reduced by up to 88%. Moreover, we demonstrated that genome engineering efficiency could be improved under a restriction–modification (R–M) deficient background, suggesting the perturbance of genome editing by other co-existing DNA targeting modules such as the R–M system. This study might shed light on exploiting and improving CRISPR–Cas systems in other microorganisms for genome editing and metabolic engineering practices.

scholarly journals Inhibition of CRISPR-Cas12a DNA targeting by nucleosomes and chromatin

2021 ◽  
Vol 7 (11) ◽  
pp. eabd6030
Author(s):  
Isabel Strohkendl ◽  
Fatema A. Saifuddin ◽  
Bryan A. Gibson ◽  
Michael K. Rosen ◽  
Rick Russell ◽  
...  
Keyword(s):  
Histone Modifications ◽  
Dna Cleavage ◽  
Genome Engineering ◽  
Eukaryotic Cells ◽  
Loop Formation ◽  
Chromatin Compaction ◽  
Dna Targeting ◽  
Genomic Regions ◽  
Dna Bendability ◽  
Nucleosome Arrays

Genome engineering nucleases must access chromatinized DNA. Here, we investigate how AsCas12a cleaves DNA within human nucleosomes and phase-condensed nucleosome arrays. Using quantitative kinetics approaches, we show that dynamic nucleosome unwrapping regulates target accessibility to Cas12a and determines the extent to which both steps of binding—PAM recognition and R-loop formation—are inhibited by the nucleosome. Relaxing DNA wrapping within the nucleosome by reducing DNA bendability, adding histone modifications, or introducing target-proximal dCas9 enhances DNA cleavage rates over 10-fold. Unexpectedly, Cas12a readily cleaves internucleosomal linker DNA within chromatin-like, phase-separated nucleosome arrays. DNA targeting is reduced only ~5-fold due to neighboring nucleosomes and chromatin compaction. This work explains the observation that on-target cleavage within nucleosomes occurs less often than off-target cleavage within nucleosome-depleted genomic regions in cells. We conclude that nucleosome unwrapping regulates accessibility to CRISPR-Cas nucleases and propose that increasing nucleosome breathing dynamics will improve DNA targeting in eukaryotic cells.

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