A Universal, Genomewide GuideFinder for CRISPR/Cas9 Targeting in Microbial Genomes

Area of Science:

• Microbiology
• Genomics
• Molecular Biology

Background:

• CRISPR/Cas9 technology offers powerful gene editing capabilities in bacteria.
• CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa) are key CRISPR/Cas9 modifications for gene regulation.
• Existing tools lack customization for designing CRISPR guides in diverse and draft bacterial genomes.

Purpose of the Study:

• To develop a user-friendly, open-source program for designing CRISPR guides in any annotated bacterial genome.
• To address limitations in existing software for bacterial CRISPR guide design, particularly for draft genomes.
• To facilitate systematic gene function studies in bacteria using CRISPR/Cas9 technology.

Main Methods:

• Developed GuideFinder, a customizable program for designing CRISPR guides.
• Utilized annotated bacterial genomes and FASTA files as input.
• Implemented filtering based on user-defined parameters and off-target matches.
• Tested guide efficacy for CRISPRi-mediated gene knockdown in staphylococcal species.

Main Results:

• GuideFinder successfully designs guides for an average of 95% of genes across diverse bacterial genomes.
• The software accommodates user-defined parameters and iterative design for challenging genes.
• Experimentally validated paired guides for targeting multiplicity.
• Demonstrated functional utility through essential gene knockdown in staphylococcal species.

Conclusions:

• GuideFinder is a versatile and effective tool for bacterial CRISPR guide design, including draft genomes.
• The open-access software enhances accessibility for CRISPR/Cas studies in a wide range of bacteria.
• GuideFinder supports systematic investigation of gene function in microbial diversity.
• The program's flexibility and features overcome limitations of previous tools.