Crispr Knockdown
Crispr Knockdown - Related Videos
02:53
CRISPR and crRNAs
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2020
Bacteria and archaea are susceptible to viral infections just like eukaryotes; therefore, they have developed a unique adaptive immune system to protect themselves. Clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins (CRISPR-Cas) are present in more than 45% of known bacteria and 90% of known archaea. The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
01:59
CRISPR
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2019
Genome editing technologies allow scientists to modify an organism’s DNA via the addition, removal, or rearrangement of genetic material at specific genomic locations. These types of techniques could potentially be used to cure genetic disorders such as hemophilia and sickle cell anemia. One popular and widely used DNA-editing research tool that could lead to safe and effective cures for genetic disorders is the CRISPR-Cas9 system. CRISPR-Cas9 stands for Clustered Regularly Interspaced Short...
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Preparation of Cell-lines for Conditional Knockdown of Gene Expression and Measurement of the Knockdown Effects on E4orf4-Induced Cell Death
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Cited by 3 •
2012
Contribution of the ACF chromatin remodeling factor to E4orf4-induced cell death was measured. The protocol includes selection of cell clones in which doxycycline treatment induces conditional knockdown of the ACF subunits Acf1 and SNF2h, and use of the DAPI assay to measure E4orf4-induced cell death in the inducible cell lines.
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A Multiwell Liquid-Based Assay for Screening C. elegans Knockdowns
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2025
Source: Anderson, Q. L. et al. A High-throughput, High-content, Liquid-based C. elegans Pathosystem. J. Vis. Exp. (2018)This video demonstrates a high-throughput screening method using Caenorhabditis elegans to study gene knockdowns during host-pathogen interactions. It outlines the procedure for preparing knockdown worms and transferring them to assay plates to evaluate the effects of pathogen-induced worm killing.
11:53
Substrate Generation for Endonucleases of CRISPR/Cas Systems
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Cited by 4 •
2012
CRISPR/Cas systems mediate adaptive immunity in Bacteria and Archaea. Many Cas proteins are proposed to act as endoribonucleases acting on crRNA precursors of varying length. Here we illustrate three different approaches to generate pre-crRNA substrates for the biochemical analysis of Cas endonuclease activity.
FAQs
CRISPR knockdown differs from a permanent knockout because it reduces gene activity without requiring a DNA-cutting event. In CRISPRi, inactive Cas9 can suppress transcription directly or recruit repressive factors, while the degree of repression may be adjusted. This reversibility lets investigators examine consequences of reduced expression and complement experiments that eliminate gene function entirely.
Target placement shapes how repression occurs. A guide can direct inactive Cas9 to a promoter, where the complex interferes with transcription, or to a coding region, where it can impede transcription. Recruitment of repressive factors adds another layer of control. These alternatives help researchers connect the location of the targeted complex with the resulting decrease in expression.
A graded reduction can reveal whether cellular behavior changes only after expression falls below a particular level, rather than showing only an all-or-none consequence. In cancer models, this distinction is relevant to genes associated with tumor growth or survival. It also supports comparison between partial suppression and complete loss of function, helping clarify how strongly a gene influences the phenotype.
A typical CRISPR knockdown design requires a selected gene, a short guide RNA, and catalytically inactive Cas9. The guide directs the protein to the gene’s promoter or coding region, enabling transcriptional blocking or recruitment of repressive factors. Researchers can then evaluate whether reduced expression changes cellular behavior, including tumor growth or survival.
In a functional genomic screen, researchers apply targeted repression across genes of interest and compare the resulting cellular behaviors. Changes in tumor growth or survival can highlight genes whose expression supports or restrains those outcomes. This makes CRISPR knockdown useful for prioritizing oncogenes, tumor-suppressor pathways, and other genes that merit investigation as possible drug targets.
Knockdown results add information about partial or reversible loss of gene activity, whereas knockout experiments examine the consequences of eliminating gene function. Comparing both outcomes can show whether a cancer-related phenotype requires complete loss or appears when expression is merely reduced. This distinction helps refine interpretations of gene function and supports evaluation of potential drug targets.