CRISPR Cheat Sheet

Posted by Tyler Ford on May 31, 2018 10:43:15 AM


CRISPR_Cheat_Sheet2At Addgene we periodically have Science Clubs where we present developments in biology research to the whole company with the goal of educating both scientists and nonscientists alike. As part of these presentations, we generally create one page cheat sheets that attendees can use to quickly reference information that they (hopefully) learn at science club. In this post you'll find our CRISPR Cheat Sheet from @megearing's recent science club presentation about genome editing and CRISPR. We hope you find this cheat sheet useful!

Download a PDF version of the CRISPR Cheat Sheet here!

 


CRISPR Cheat Sheet

Genome Editing:

  • Modifying the DNA sequence of an organism’s genome usually for a research or applied goal

CRISPR - Clustered Regularly Interspaced Short Palindromic Repeats:

  • Sequences of DNA found in bacteria that allow the bacteria to target and destroy viruses that infect them. Commonly referred to as a bacterial immune system.

Natural CRISPR Systems Have 2 Major Components

1. Repeat Regions:

  • These are used to create gRNAs - sequences of RNA that direct the CRISPR system to cut other DNA sequences.
2. Nucleases:
    • Proteins that bind to gRNAs and are directed by the gRNAs to cut particular DNA sequences. Cas9 is a very commonly used CRISPR nuclease

*Note* - Most CRISPR plasmids from Addgene are used to produce either a gRNA or a nuclease or both

Some Applications of CRISPR

  • Knockout:
    • CRISPR can be used to cut the DNA sequence of a gene making it so that the gene no longer encodes a functional protein
    • Knockout experiments give researchers an idea of the role a gene plays in normal biology
  • Knockin:
    • CRISPR can be used to facilitate a functional change in a DNA sequence that may give cells or organisms new or modified genes with new or modified functionality
    • Knockins place repair templates encoding the desired DNA change into the genome - the CRISPR system cuts the DNA, but the target cells use the repair template to fix the cut, thereby acquiring the function encoded by the repair template
  • Base editors:
    • Modified versions of CRISPR nucleases that make single letter changes in DNA sequence without completely cutting the DNA

  • Activate/Repress:
    • Modified versions of CRISPR nucleases that can no-longer cut DNA (dCas9 for example) can be used to increase or decrease the production of a protein encoded by a gene

  • RNA Editors:
    • CRISPR nucleases that cut or modify RNA as opposed to DNA

Limitations of CRISPR

  • Precise edits are difficult
  • CRISPR is not always 100% specific - i.e. it can cut DNA sequences that researchers don’t intend it to
  • CRISPR cannot cut all sequences - certain requirements of CRISPR systems prevent them from targeting all sequences
  • CRISPR can be difficult to deliver - Not all cells efficiently take up plasmids used to produce CRISPR systems

Click to Download Addgene's CRISPR 101 eBook

 

Topics: CRISPR, Genome Engineering

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