This
paper offers a general review and comparative analysis of various types of Clustered Regularly Interspaced Short
Palindromic Repeats (CRISPR) technologies. It evaluates the strengths
and weaknesses of these technologies to identify
the optimal approach for conducting genetic screens. Through an extensive literature review, this paper examines CRISPR nuclease, CRISPR
activation (CRISPRa), and CRISPR interference (CRISPRi) screens. This study
concludes that CRISPRa and CRISPRi are more advantageous due to their use of
deactivated Cas9 proteins that only over-express or deactivate genes rather
than irreversibly breaking genes like CRISPRn. Notably, CRISPRa is unique in
its ability to over-express genes, while the other two technologies deactivate
genes. Future studies may focus on inducing multiple mutations simultaneously—both gain-of-function and gene knockout—to
carry out a more complete screen that can test the combinatorial effect
of genes. Likewise, targeting both exons and introns can offer a more thorough
understanding of a specific phenotype.
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