scholarly journals CrispRdesignR: A Versatile Guide RNA Design Package in R for CRISPR/Cas9 Applications

2019 ◽  
Author(s):  
Dylan Beeber ◽  
Frédéric JJ Chain

AbstractThe success of CRISPR/Cas9 gene editing applications relies on the efficiency of the single guide RNA (sgRNA) used in conjunction with the Cas9 protein. Current sgRNA design software vary in the details they provide on sgRNA sequence efficiency and are almost exclusively restricted to model organisms. The crispRdesignR package aims to address these limitations by providing comprehensive sequence features of the generated sgRNAs in a single program, which allows users to predict sgRNA efficiency and design sgRNA sequences for systems that currently do not have optimized efficiency scoring methods. crispRdesignR reports extensive information on all designed sgRNA sequences with robust off-target calling and annotation and can be run in a user-friendly graphical interface. The crispRdesignR package is implemented in R and has fully editable code for specialized purposes including sgRNA design in user-provided genomes. The package is platform independent and extendable, with its source code and documentation freely available at https://github.com/dylanbeeber/crispRdesignR.

2019 ◽  
Author(s):  
Chiao-Lin Chen ◽  
Jonathan Rodiger ◽  
Verena Chung ◽  
Raghuvir Viswanatha ◽  
Stephanie E. Mohr ◽  
...  

ABSTRACTCRISPR-Cas9 is a powerful genome editing technology in which a single guide RNA (sgRNA) confers target site specificity to achieve Cas9-mediated genome editing. Numerous sgRNA design tools have been developed based on reference genomes for humans and model organisms. However, existing resources are not optimal as genetic mutations or single nucleotide polymorphisms (SNPs) within the targeting region affect the efficiency of CRISPR-based approaches by interfering with guide-target complementarity. To facilitate identification of sgRNAs (1) in non-reference genomes, (2) across varying genetic backgrounds, or (3) for specific targeting of SNP-containing alleles, for example, disease relevant mutations, we developed a web tool, SNP-CRISPR (https://www.flyrnai.org/tools/snp_crispr/). SNP-CRISPR can be used to design sgRNAs based on public variant data sets or user-identified variants. In addition, the tool computes efficiency and specificity scores for sgRNA designs targeting both the variant and the reference. Moreover, SNP-CRISPR provides the option to upload multiple SNPs and target single or multiple nearby base changes simultaneously with a single sgRNA design. Given these capabilities, SNP-CRISPR has a wide range of potential research applications in model systems and for design of sgRNAs for disease-associated variant correction.


2020 ◽  
Author(s):  
Xinyi Guo ◽  
Hans-Hermann Wessels ◽  
Alejandro Méndez-Mancilla ◽  
Daniel Haro ◽  
Neville E. Sanjana

AbstractCRISPR-Cas13 mediates robust transcript knockdown in human cells through direct RNA targeting. Compared to DNA-targeting CRISPR enzymes like Cas9, RNA targeting by Cas13 is transcript- and strand-specific: It can distinguish and specifically knock-down processed transcripts, alternatively spliced isoforms and overlapping genes, all of which frequently serve different functions. Previously, we identified optimal design rules for RfxCas13d guide RNAs (gRNAs), and developed a computational model to predict gRNA efficacy for all human protein-coding genes. However, there is a growing interest to target other types of transcripts, such as noncoding RNAs (ncRNAs) or viral RNAs, and to target transcripts in other commonly-used organisms. Here, we predicted relative Cas13-driven knock-down for gRNAs targeting messenger RNAs and ncRNAs in six model organisms (human, mouse, zebrafish, fly, nematode and flowering plants) and four abundant RNA virus families (SARS-CoV-2, HIV-1, H1N1 influenza and MERS). To allow for more flexible gRNA efficacy prediction, we also developed a web-based application to predict optimal gRNAs for any RNA target entered by the user. Given the lack of Cas13 guide design tools, we anticipate this resource will facilitate CRISPR-Cas13 RNA targeting in common model organisms, emerging viral threats to human health, and novel RNA targets.


2017 ◽  
Author(s):  
Brian J. Mendoza ◽  
Cong T. Trinh

AbstractMotivationGenetic diversity of non-model organisms offers a repertoire of unique phenotypic features for exploration and cultivation for synthetic biology and metabolic engineering applications. To realize this enormous potential, it is critical to have an efficient genome editing tool for rapid strain engineering of these organisms to perform novel programmed functions.ResultsTo accommodate the use of CRISPR/Cas systems for genome editing across organisms, we have developed a novel method, named CASPER (CRISPR Associated Software for Pathway Engineering and Research), for identifying on- and off-targets with enhanced predictability coupled with an analysis of non-unique (repeated) targets to assist in editing any organism with various endonucleases. Utilizing CASPER, we demonstrated a modest 2.4% and significant 30.2% improvement (F-test, p<0.05) over the conventional methods for predicting on- and off-target activities, respectively. Further we used CASPER to develop novel applications in genome editing: multitargeting analysis (i.e. simultaneous multiple-site modification on a target genome with a sole guide-RNA (gRNA) requirement) and multispecies population analysis (i.e. gRNA design for genome editing across a consortium of organisms). Our analysis on a selection of industrially relevant organisms revealed a number of non-unique target sites associated with genes and transposable elements that can be used as potential sites for multitargeting. The analysis also identified shared and unshared targets that enable genome editing of single or multiple genomes in a consortium of interest. We envision CASPER as a useful platform to enhance the precise CRISPR genome editing for metabolic engineering and synthetic biology applications.


2019 ◽  
Vol 10 (2) ◽  
pp. 489-494 ◽  
Author(s):  
Chiao-Lin Chen ◽  
Jonathan Rodiger ◽  
Verena Chung ◽  
Raghuvir Viswanatha ◽  
Stephanie E. Mohr ◽  
...  

CRISPR-Cas9 is a powerful genome editing technology in which a single guide RNA (sgRNA) confers target site specificity to achieve Cas9-mediated genome editing. Numerous sgRNA design tools have been developed based on reference genomes for humans and model organisms. However, existing resources are not optimal as genetic mutations or single nucleotide polymorphisms (SNPs) within the targeting region affect the efficiency of CRISPR-based approaches by interfering with guide-target complementarity. To facilitate identification of sgRNAs (1) in non-reference genomes, (2) across varying genetic backgrounds, or (3) for specific targeting of SNP-containing alleles, for example, disease relevant mutations, we developed a web tool, SNP-CRISPR (https://www.flyrnai.org/tools/snp_crispr/). SNP-CRISPR can be used to design sgRNAs based on public variant data sets or user-identified variants. In addition, the tool computes efficiency and specificity scores for sgRNA designs targeting both the variant and the reference. Moreover, SNP-CRISPR provides the option to upload multiple SNPs and target single or multiple nearby base changes simultaneously with a single sgRNA design. Given these capabilities, SNP-CRISPR has a wide range of potential research applications in model systems and for design of sgRNAs for disease-associated variant correction.


Cell Genomics ◽  
2021 ◽  
pp. 100001
Author(s):  
Xinyi Guo ◽  
Jahan A. Rahman ◽  
Hans-Hermann Wessels ◽  
Alejandro Méndez-Mancilla ◽  
Daniel Haro ◽  
...  

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Yan Zhang ◽  
Ping Zhou ◽  
Tohir A. Bozorov ◽  
Daoyuan Zhang

Abstract Background Xinjiang wild apple is an important tree of the Tianshan Mountains, and in recent years, it has undergone destruction by many biotic and abiotic stress and human activities. It is necessary to use new technologies to research its genomic function and molecular improvement. The clustered regulatory interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) system has been successfully applied to genetic improvement in many crops, but its editing capability varies depending on the different combinations of the synthetic guide RNA (sgRNA) and Cas9 protein expression devices. Results In this study, we used 2 systems of vectors with paired sgRNAs targeting to MsPDS. As expected, we successfully induced the albino phenotype of calli and buds in both systems. Conclusions We conclude that CRISPR/Cas9 is a powerful system for editing the wild apple genome and expands the range of plants available for gene editing.


2021 ◽  
Vol 22 (S6) ◽  
Author(s):  
Yasmine Mansour ◽  
Annie Chateau ◽  
Anna-Sophie Fiston-Lavier

Abstract Background Meiotic recombination is a vital biological process playing an essential role in genome's structural and functional dynamics. Genomes exhibit highly various recombination profiles along chromosomes associated with several chromatin states. However, eu-heterochromatin boundaries are not available nor easily provided for non-model organisms, especially for newly sequenced ones. Hence, we miss accurate local recombination rates necessary to address evolutionary questions. Results Here, we propose an automated computational tool, based on the Marey maps method, allowing to identify heterochromatin boundaries along chromosomes and estimating local recombination rates. Our method, called BREC (heterochromatin Boundaries and RECombination rate estimates) is non-genome-specific, running even on non-model genomes as long as genetic and physical maps are available. BREC is based on pure statistics and is data-driven, implying that good input data quality remains a strong requirement. Therefore, a data pre-processing module (data quality control and cleaning) is provided. Experiments show that BREC handles different markers' density and distribution issues. Conclusions BREC's heterochromatin boundaries have been validated with cytological equivalents experimentally generated on the fruit fly Drosophila melanogaster genome, for which BREC returns congruent corresponding values. Also, BREC's recombination rates have been compared with previously reported estimates. Based on the promising results, we believe our tool has the potential to help bring data science into the service of genome biology and evolution. We introduce BREC within an R-package and a Shiny web-based user-friendly application yielding a fast, easy-to-use, and broadly accessible resource. The BREC R-package is available at the GitHub repository https://github.com/GenomeStructureOrganization.


2021 ◽  
Vol 22 (6) ◽  
pp. 2937
Author(s):  
Monika Halat ◽  
Magdalena Klimek-Chodacka ◽  
Jagoda Orleanska ◽  
Malgorzata Baranska ◽  
Rafal Baranski

The Streptococcus pyogenes Cas9 protein (SpCas9), a component of CRISPR-based immune system in microbes, has become commonly utilized for genome editing. This nuclease forms a ribonucleoprotein (RNP) complex with guide RNA (gRNA) which induces Cas9 structural changes and triggers its cleavage activity. Here, electronic circular dichroism (ECD) spectroscopy was used to confirm the RNP formation and to determine its individual components. The ECD spectra had characteristic features differentiating Cas9 and gRNA, the former showed a negative/positive profile with maxima located at 221, 209 and 196 nm, while the latter revealed positive/negative/positive/negative pattern with bands observed at 266, 242, 222 and 209 nm, respectively. For the first time, the experimental ECD spectrum of the gRNA:Cas9 RNP complex is presented. It exhibits a bisignate positive/negative ECD couplet with maxima at 273 and 235 nm, and it differs significantly from individual spectrum of each RNP components. Additionally, the Cas9 protein and RNP complex retained biological activity after ECD measurements and they were able to bind and cleave DNA in vitro. Hence, we conclude that ECD spectroscopy can be considered as a quick and non-destructive method of monitoring conformational changes of the Cas9 protein as a result of Cas9 and gRNA interaction, and identification of the gRNA:Cas9 RNP complex.


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