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Reference Icon RedbookGenome Engineering Guide


Plasmid and wrench icon

Addgene's plasmid repository contains a variety of tools to target and edit genomes. Use this guide to learn more about the genome engineering technologies and find the plasmids that are available from Addgene's depositing scientists.

CRISPR Technology

RNA-guided endonucleases (RGEN) utilize a short guide RNA (gRNA) to recognize DNA, bind an endonuclease, and induce site specific cleavage. New RGEN technologies are popularly referred to as CRISPR systems, derived from the clustered regularly interspaced short palindromic repeats (CRISPR) found in bacteria that serve to identify and destroy foreign DNA. CRISPR genome editing systems allow users to design gRNA which target their DNA sequence of interest. When expressed intracellularly in conjunction with a CRISPR associated endonuclease (Cas9), the gRNA directs Cas9 to the target sequence where it unwinds and cleaves the double stranded DNA.

The CRISPR genome editing systems are comprised of only 2 to 3 plasmids, expressing the gRNA and the Cas9 nuclease. These systems are easily tuned for targeting specificity by inserting a complementary oligo into the gRNA expression vector. Additionally, various CRISPR systems for genome editing have been developed for use in different cell types.

CRISPR/Cas cartoon

Reference Guides:

Plasmids Available at Addgene:


TALEN Technology

Transcription activator-like effector nuclease (TALEN) systems are a fusion of TALEs derived from the Xanthomonas spp. to a restriction endonuclease FokI. By modifying the amino acid repeats in the TALEs, users can customize TALEN systems to specifically bind target DNA and induce cleavage by the nuclease between the two distinct TAL array binding sites. A variety of plasmid kits, which include from 12 to 86 plasmids, are available from Addgene and allow for the creation of custom repeat arrays for easy TALEN preparation. The different TALEN tool kits use various cloning techniques and protocols to enable custom TALEN design and preparation.

TALEN cartoon

Reference Guides:

Plasmids Available at Addgene:


Zinc Finger Technology

Zinc finger nuclease (ZFN) technology utilizes a FokI nuclease as the DNA-cleavage domain and binds DNA by engineered Cys2His2 zinc fingers. Specific zinc fingers recognize different nucleotide triplets and dimerize the FokI nuclease. The activated nuclease introduces a double stranded break between the two distinct zinc finger binding sites, which prompts recombination and modification of the genome.

Zinc Finger cartoon

Plasmids Available at Addgene:

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