CRISPR Screening for Essential Genes in Microbes
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Solution Overview
Problem
Current methods lack efficiency in screening for essential and non-essential genes, expendable genomic islands, and reducing genome size in bacteria, archaea, algae, and yeast, as well as effectively killing specific bacterial cells or identifying phenotypes, due to limitations in precision and specificity of existing CRISPR-Cas systems.
Innovation Solution
Introducing heterologous nucleic acid constructs with CRISPR arrays and Cas9 polypeptides into bacterial, archaeal, algal, or yeast cells to selectively target and delete specific genomic regions, using Type I, II, III, IV, or V CRISPR systems, allowing for the identification of essential genes, expendable islands, and reduced genome size, as well as killing specific cells by introducing CRISPR arrays and Cas9 polypeptides that are complementary to target regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional screening methods are used to identify essential and non-essential genes, then the screening process can be performed, but the precision and specificity are insufficient leading to inaccurate identification of target genes
Solution Approach 1:
The genome is divided into multiple target regions, each assigned a specific spacer sequence in the CRISPR array. This segmentation allows simultaneous targeting of multiple genes or genomic regions, enabling high-throughput screening of essential and non-essential genes with precise identification while reducing the time required compared to traditional sequential methods.
Solution Approach 2:
The CRISPR-Cas9 system acts as an intermediary between the screening objective and the target genome. The guide RNA (spacer sequence) mediates specific recognition of target regions, while the Cas9 nuclease executes the gene disruption. This intermediary mechanism provides both high precision in target identification and efficiency in screening throughput.
2Measurement precision
If CRISPR-Cas9 system is introduced to achieve precise gene targeting, then screening precision is improved, but the system complexity increases
Solution Approach 1:
The CRISPR-Cas9 system provides universal applicability across different bacterial, archaeal, algal, and yeast species. The same basic mechanism (CRISPR array + Cas9 nuclease) can target any genomic region by simply changing the spacer sequence, eliminating the need for species-specific or gene-specific complex delivery systems. This multi-functionality reduces overall system complexity while maintaining high targeting precision.
Solution Approach 2:
The system allows easy modification of targeting parameters by changing the spacer sequence in the CRISPR array. Different spacer sequences can be introduced to target different genes or regions without altering the core Cas9 machinery. This parameter-based flexibility simplifies the system design compared to traditional methods that require different molecular tools for each target.
3Adaptability or versatility
If multiple CRISPR arrays are introduced to screen multiple target regions, then screening coverage is improved, but the transformation complexity and time required increase
Solution Approach 1:
Multiple CRISPR arrays targeting different genomic regions are merged into a single heterologous nucleic acid construct. This consolidated construct can be introduced into the host cell in one transformation event, achieving simultaneous targeting of multiple essential and non-essential genes. This approach provides comprehensive screening coverage while significantly reducing the cumulative transformation time compared to sequential introduction of separate constructs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise screening for essential and non-essential genes, identification of phenotypes, and reduction of genome size, while allowing for sequence-specific killing of bacterial cells, thereby enriching populations lacking target sequences, demonstrating enhanced specificity and efficiency in genetic manipulation.
Implementation Method 1
the spacer of said repeat-spacer-repeat sequence or said at least one repeat-spacer sequence comprises a nucleotide sequence that is substantially complementary to a target region in the genome
Implementation Method 2
Cas9 endonuclease that cleaves double-stranded DNA at a target site
Implementation Method 3
The cell repair mechanisms can then be relied upon to resolve the double-strand breaks
Data Source
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AI summary
This invention relates to the use of CRISPR nucleic acids to screen for essential and non-essential genes and expendable genomic islands in bacteria, archaea, algae and/or yeast, to kill bacteria, archaea, algae and/or yeast, to identify the phenotype of a gene or genes, and/or to screen for reduced genome size and/or a gene deletion in bacteria, archaea, algae and/or yeast.