scholarly journals Transcriptome-wide Cas13 guide RNA design for model organisms and viral RNA pathogens

2020 ◽  
Author(s):  
Xinyi Guo ◽  
Hans-Hermann Wessels ◽  
Alejandro Méndez-Mancilla ◽  
Daniel Haro ◽  
Neville E. Sanjana
Keyword(s):  
Rna Virus ◽  
H1n1 Influenza ◽  
Model Organisms ◽  
Messenger Rnas ◽  
Protein Coding ◽  
Guide Rna ◽  
Knock Down ◽  
Guide Rnas ◽  
Rna Targeting ◽  
Rna Design

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.

scholarly journals Principles for rational Cas13d guide design

2019 ◽  
Author(s):  
Hans-Hermann Wessels ◽  
Alejandro Méndez-Mancilla ◽  
Xinyi Guo ◽  
Mateusz Legut ◽  
Zharko Daniloski ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Perfect Match ◽  
Nuclease Activity ◽  
Target Site ◽  
Surface Proteins ◽  
Protein Coding ◽  
Guide Rna ◽  
Knock Down ◽  
Guide Rnas ◽  
Green Fluorescent

AbstractType VI CRISPR enzymes have recently been identified as programmable RNA-guided, RNA-targeting Cas proteins with nuclease activity that allow for specific and robust target gene knock-down without altering the genome. However, we currently lack information about optimal Cas13 guide RNA designs for high target RNA knock-down efficacy. To close this gap, we conducted four massively-parallel Cas13 screens targeting the mRNA of a destabilized green fluorescent protein (GFP) transgene and CD46, CD55 and CD71 cell surface proteins in human cells. In total, we measured the activity of 24,460 guide RNA including 6,469 perfect match guide RNAs and a diverse set of guide RNA variants and permutations with mismatches relative to the target sequences.We find that guide RNAs show high diversity in knock-down efficiency driven by crRNA-specific features as well as target site context. Moreover, while single mismatches generally reduce knock-down to a modest degree, we identify a critical region spanning spacer nucleotides 15 – 21 that is largely intolerant to target site mismatches. We developed a computational model to identify guide RNAs with high knock-down efficacy. We confirmed the model’s generalizability across a large number of endogenous target mRNAs and show that Cas13 can be used in forward genetic pooled CRISPR-screens to identify essential genes. Using this model, we provide a resource of optimized Cas13 guide RNAs to target all protein-coding transcripts in the human genome, enabling transcriptome-wide forward genetic screens.

scholarly journals kRISP-meR: A Reference-free Guide-RNA Design Tool for CRISPR/Cas9

2019 ◽  
Author(s):  
Mahmudur Rahman Hera ◽  
Amatur Rahman ◽  
Atif Rahman
Keyword(s):  
Genome Editing ◽  
Design Tool ◽  
Target Region ◽  
Guide Rna ◽  
Guide Rnas ◽  
Rna Design ◽  
Reference Genomes ◽  
Target Effects

AbstractGenome editing using the CRISPR/Cas9 system requires designing guide RNAs (sgRNA) that are efficient and specific. Guide RNAs are usually designed using reference genomes which limits their use in organisms with no or incomplete reference genomes. Here, we present kRISP-meR, a reference free method to design sgRNAs for CRISPR/Cas9 system. kRISP-meR takes as input a target region and sequenced reads from the organism to be edited and generates sgRNAs that are likely to minimize off-target effects. Our analysis indicates that kRISP-meR is able to identify majority of the guides identified by a widely used sgRNA designing tool, without any knowledge of the reference, while retaining specificity.

scholarly journals Enhanced guide-RNA Design and Targeting Analysis for Precise CRISPR Genome Editing of Single and Consortia of Industrially Relevant and Non-Model Organisms

2017 ◽  
Author(s):  
Brian J. Mendoza ◽  
Cong T. Trinh
Keyword(s):  
Metabolic Engineering ◽  
Synthetic Biology ◽  
Genome Editing ◽  
Population Analysis ◽  
Strain Engineering ◽  
Pathway Engineering ◽  
Model Organisms ◽  
Guide Rna ◽  
Novel Applications ◽  
Rna Design

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.

scholarly journals CRISpy-pop: a web tool for designing CRISPR/Cas9-driven genetic modifications in diverse populations

2020 ◽  
Author(s):  
Hayley R. Stoneman ◽  
Russell L. Wrobel ◽  
Michael Place ◽  
Michael Graham ◽  
David J. Krause ◽  
...  
Keyword(s):  
Web Application ◽  
Genomic Data ◽  
Model Organisms ◽  
Bacterial Strains ◽  
Rna Sequences ◽  
Guide Rna ◽  
Guide Rnas ◽  
Population Genomic ◽  
Current Implementation ◽  
Multiple Strains

AbstractCRISPR/Cas9 is a powerful tool for editing genomes, but design decisions are generally made with respect to a single reference genome. With population genomic data becoming available for an increasing number of model organisms, researchers are interested in manipulating multiple strains and lines. CRISpy-pop is a web application that generates and filters guide RNA sequences for CRISPR/Cas9 genome editing for diverse yeast and bacterial strains. The current implementation designs and predicts the activity of guide RNAs against more than 1000 Saccharomyces cerevisiae genomes, including 167 strains frequently used in bioenergy research. Zymomonas mobilis, an increasingly popular bacterial bioenergy research model, is also supported. CRISpy-pop is available as a web application (https://CRISpy-pop.glbrc.org/) with an intuitive graphical user interface. CRISpy-pop also cross-references the human genome to allow users to avoid the selection of sgRNAs with potential biosafety concerns. Additionally, CRISpy-pop predicts the strain coverage of each guide RNA within the supported strain sets, which aids in functional population genetic studies. Finally, we validate how CRISpy-pop can accurately predict the activity of guide RNAs across strains using population genomic data.

scholarly journals Effective RNA Knockdown Using CRISPR-Cas13a and Molecular Targeting of the EML4-ALK Transcript in H3122 Lung Cancer Cells

2020 ◽  
Vol 21 (23) ◽  
pp. 8904
Author(s):  
Saifullah ◽  
Matomo Sakari ◽  
Takeshi Suzuki ◽  
Seiji Yano ◽  
Toshifumi Tsukahara
Keyword(s):  
Lung Cancer ◽  
Cancer Cells ◽  
Firefly Luciferase ◽  
Lung Cancer Cells ◽  
Guide Rna ◽  
Knock Down ◽  
Guide Rnas ◽  
Rnai Technology ◽  
Low Efficiency ◽  
The Stability

RNAi technology has significant potential as a future therapeutic and could theoretically be used to knock down disease-specific RNAs. However, due to frequent off-target effects, low efficiency, and limited accessibility of nuclear transcripts, the clinical application of the technology remains challenging. In this study, we first assessed the stability of Cas13a mRNA and guide RNA. Next, we titrated Cas13a and guide RNA vectors to achieve effective knockdown of firefly luciferase (FLuc) RNA, used as a target transcript. The interference specificity of Cas13a on guide RNA design was next explored. Subsequently, we targeted the EML4-ALK v1 transcript in H3122 lung cancer cells. As determined by FLuc assay, Cas13a exhibited activity only toward the orientation of the crRNA–guide RNA complex residing at the 5′ of the crRNA. The activity of Cas13a was maximal for guide RNAs 24–30 bp in length, with relatively low mismatch tolerance. After knockdown of the EML4-ALK transcript, cell viability was decreased up to 50%. Cas13a could effectively knock down FLuc luminescence (70–76%), mCherry fluorescence (72%), and EML4-ALK at the protein (>80%) and transcript levels (26%). Thus, Cas13a has strong potential for use in RNA regulation and therapeutics, and could contribute to the development of personalized medicine.

scholarly journals CRISpy-Pop: A Web Tool for Designing CRISPR/Cas9-Driven Genetic Modifications in Diverse Populations

2020 ◽  
Vol 10 (11) ◽  
pp. 4287-4294
Author(s):  
Hayley R. Stoneman ◽  
Russell L. Wrobel ◽  
Michael Place ◽  
Michael Graham ◽  
David J. Krause ◽  
...  
Keyword(s):  
Web Application ◽  
Genomic Data ◽  
Model Organisms ◽  
Bacterial Strains ◽  
Rna Sequences ◽  
Guide Rna ◽  
Guide Rnas ◽  
Population Genomic ◽  
Current Implementation ◽  
Multiple Strains

CRISPR/Cas9 is a powerful tool for editing genomes, but design decisions are generally made with respect to a single reference genome. With population genomic data becoming available for an increasing number of model organisms, researchers are interested in manipulating multiple strains and lines. CRISpy-pop is a web application that generates and filters guide RNA sequences for CRISPR/Cas9 genome editing for diverse yeast and bacterial strains. The current implementation designs and predicts the activity of guide RNAs against more than 1000 Saccharomyces cerevisiae genomes, including 167 strains frequently used in bioenergy research. Zymomonas mobilis, an increasingly popular bacterial bioenergy research model, is also supported. CRISpy-pop is available as a web application (https://CRISpy-pop.glbrc.org/) with an intuitive graphical user interface. CRISpy-pop also cross-references the human genome to allow users to avoid the selection of guide RNAs with potential biosafety concerns. Additionally, CRISpy-pop predicts the strain coverage of each guide RNA within the supported strain sets, which aids in functional population genetic studies. Finally, we validate how CRISpy-pop can accurately predict the activity of guide RNAs across strains using population genomic data.

scholarly journals CRISPR as a Potential Technique to Reduce Suicide Risk

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Hidemi Zamora ◽  
Javier Cornejo
Keyword(s):  
Cystic Fibrosis ◽  
Suicide Risk ◽  
Gene Editing ◽  
Design Tool ◽  
High Importance ◽  
Knock Out ◽  
Guide Rna ◽  
Guide Rnas ◽  
The Past ◽  
Rna Design

As suicide is the nineteenth leading cause of death worldwide, it is important to focus on discovering ways to reduce the risk of suicide-related death as much as possible. With CRISPR starting to become increasingly popular over the past few years, this gene editing technique has been used to study how to edit, turn off, or knock out multiple parts of the genome. However, research on genes related to diseases as cystic fibrosis or Alzheimer’s disease has been mainly prioritized and, even though they are of high importance as well, important issues such as suicide have been left into oblivion. Four genes have been proven to be key in influencing suicide risk, showing that not only environmental factors account for an increased possibility of death by this cause. Therefore, gene editing techniques such as CRISPR could be applied in order to knock out those genes and reduce this risk. This research used Synthego’s guide RNA design tool to predict how the use of CRISPR can be helpful in knocking out those four suicide-related genes and, consequently, in preventing suicide. The top-ranked guide RNAs for each gene were used, showing the best results possible and with the least number of off-targets, which, in turn, demonstrates the effectiveness of CRISPR as a potential technique to reduce the number of suicide-related deaths worldwide.

scholarly journals Structural basis for the RNA-guided ribonuclease activity of CRISPR-Cas13d

2018 ◽  
Author(s):  
Cheng Zhang ◽  
Silvana Konermann ◽  
Nicholas J. Brideau ◽  
Peter Lotfy ◽  
Scott J. Novick ◽  
...  
Keyword(s):  
Conformational Dynamics ◽  
Enzyme Activation ◽  
Structural Basis ◽  
Binary Complex ◽  
Molecular Architecture ◽  
Guide Rna ◽  
Guide Rnas ◽  
Rna Targeting ◽  
Hydrogen Deuterium ◽  
Target Rna

AbstractCRISPR-Cas endonucleases directed against foreign nucleic acids mediate prokaryotic adaptive immunity and have been tailored for broad genetic engineering applications. Type VI-D CRISPR systems contain the smallest known family of single effector Cas enzymes, and their signature Cas13d ribonuclease employs guide RNAs to cleave matching target RNAs. To understand the molecular basis for Cas13d function, we resolved cryo-electron microscopy structures of Cas13d-guide RNA binary complex and Cas13d-guide-target RNA ternary complex to 3.4 and 3.3 Å resolution, respectively. Furthermore, a 6.5 Å reconstruction of apo Cas13d combined with hydrogen-deuterium exchange revealed conformational dynamics that have implications for RNA scanning. These structures, together with biochemical and cellular characterization, explain the compact molecular architecture of Cas13d and provide insights into the structural transitions required for enzyme activation. Our comprehensive analysis of Cas13d in diverse enzymatic states facilitated site-specific truncations for minimal size and delineates a blueprint for improving biomolecular applications of RNA targeting.

scholarly journals Human Box H/ACA Pseudouridylation Guide RNA Machinery

2004 ◽  
Vol 24 (13) ◽  
pp. 5797-5807 ◽  
Author(s):  
Arnold M. Kiss ◽  
Beáta E. Jády ◽  
Edouard Bertrand ◽  
Tamás Kiss
Keyword(s):  
Protein Product ◽  
Protein Coding ◽  
Guide Rna ◽  
Guide Rnas ◽  
Small Nuclear Rnas ◽  
Spliceosomal Rnas ◽  
Coding Capacity ◽  
Rna Genes ◽  
Specific Synthesis

ABSTRACT Pseudouridine, the most abundant modified nucleoside in RNA, is synthesized by posttranscriptional isomerization of uridines. In eukaryotic RNAs, site-specific synthesis of pseudouridines is directed primarily by box H/ACA guide RNAs. In this study, we have identified 61 novel putative pseudouridylation guide RNAs by construction and characterization of a cDNA library of human box H/ACA RNAs. The majority of the new box H/ACA RNAs are predicted to direct pseudouridine synthesis in rRNAs and spliceosomal small nuclear RNAs. We can attribute RNA-directed modification to 79 of the 97 pseudouridylation sites present in the human 18S, 5.8S, and 28S rRNAs and to 11 of the 21 pseudouridines reported for the U1, U2, U4, U5, and U6 spliceosomal RNAs. We have also identified 12 novel box H/ACA RNAs which lack apparent target pseudouridines in rRNAs and small nuclear RNAs. These putative guide RNAs likely function in the pseudouridylation of some other types of cellular RNAs, suggesting that RNA-guided pseudouridylation is more general than assumed before. The genomic organization of the new box H/ACA RNA genes indicates that in human cells, all box H/ACA pseudouridylation guide RNAs are processed from introns of pre-mRNA transcripts which either encode a protein product or lack protein-coding capacity.

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