Background: CRISPR-Cas systems have expanded the possibilities for gene editing in bacteria and eukaryotes. There are many excellent tools for designing CRISPR-Cas guide RNAs (gRNAs) for model organisms with standard Cas enzymes. GuideMaker is intended as a fast and easy-to-use design tool for challenging projects with (i) non-standard Cas enzymes, (ii) non-model organisms, or (iii) projects that need to design a panel of gRNA for genome-wide screens.
Findings: GuideMaker can rapidly design gRNAs for gene targets across the genome using a degenerate protospacer-adjacent motif (PAM) and a genome. The tool applies hierarchical navigable small world graphs to speed up the comparison of guide RNAs and optionally provides on-target and off-target scoring. This allows the user to design effective gRNAs targeting all genes in a typical bacterial genome in ∼1-2 minutes.
Conclusions: GuideMaker enables the rapid design of genome-wide gRNA for any CRISPR-Cas enzyme in non-model organisms. While GuideMaker is designed with prokaryotic genomes in mind, it can efficiently process eukaryotic genomes as well. GuideMaker is available as command-line software, a stand-alone web application, and a tool in the CyCverse Discovery Environment. All versions are available under a Creative Commons CC0 1.0 Universal Public Domain Dedication.
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http://dx.doi.org/10.1093/gigascience/giac007 | DOI Listing |
The most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) is an intronic GC repeat expansion in C9orf72. The repeats undergo bidirectional transcription to produce sense and antisense repeat RNA species, which are translated into dipeptide repeat proteins (DPRs). As toxicity has been associated with both sense and antisense repeat-derived RNA and DPRs, targeting both strands may provide the most effective therapeutic strategy.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada.
The ability to determine the essentiality of a gene in the protozoan parasite Leishmania is important to identify potential targets for intervention and understanding the parasite biology. CRISPR gene editing technology has significantly improved gene targeting efficiency in Leishmania. There are two commonly used CRISPR gene targeting methods in Leishmania; the stable expression of the gRNA and Cas9 using a plasmid containing a Leishmania ribosomal RNA gene promoter (rRNA-P stable protocol) and the T7 RNA polymerase based transient gRNA expression system in promastigotes stably expressing Cas9 (T7 transient protocol).
View Article and Find Full Text PDFNat Commun
January 2025
Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin, Austin, TX, 78712, USA.
Type II CRISPR endonucleases are widely used programmable genome editing tools. Recently, CRISPR-Cas systems with highly compact nucleases have been discovered, including Cas9d (a type II-D nuclease). Here, we report the cryo-EM structures of a Cas9d nuclease (747 amino acids in length) in multiple functional states, revealing a stepwise process of DNA targeting involving a conformational switch in a REC2 domain insertion.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Laboratory Animal Resource Center, Transborder Medical Research Center, Institute of Medicine, University of Tsukuba, Tsukuba 305-8575, Japan.
With the groundbreaking advancements in genome editing technologies, particularly CRISPR-Cas9, creating knockout mutants has become highly efficient. However, the CRISPR-Cas9 system introduces DNA double-strand breaks, increasing the risk of chromosomal rearrangements and posing a major obstacle to simultaneous multiple gene knockout. Base-editing systems, such as Target-AID, are safe alternatives for precise base modifications without requiring DNA double-strand breaks, serving as promising solutions for existing challenges.
View Article and Find Full Text PDFBiosci Microbiota Food Health
September 2024
Department of Agricultural Chemistry, Graduate School of Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
Although the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas system has been extensively developed since its discovery for eukaryotic and prokaryotic genome editing and other genetic manipulations, there are still areas warranting improvement, especially regarding bacteria. In this study, BRD0539, a small-molecule inhibitor of Cas9 (SpCas9), was used to suppress the activity of the nuclease during genetic modification of , as well as to regulate CRISPR interference (CRISPRi). First, we developed and validated a CRISPR-SpCas9 system targeting the gene of .
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