Accelerate science further with innovative genome editing technology

Transcription activator-like (TAL) effector proteins are a novel class of DNA binding proteins. Engineering them enables precise genome editing, helping create tools to advance life science research and applied fields.

TAL effector proteins are naturally occurring transcriptional activators secreted by Xanthamonas spp. into their plant hosts via a Type III secretion system. They travel to the nucleus where they bind to and activate specific promoter sequences, leading to changes that are permissive for bacterial infection1.

TAL effector proteins consist of constant N- and C-terminal domains flanking a central repeat domain. Each repeat is 34–35 amino acids in length, with two centrally located residues that make up a repeat variable domain (RVD) that dictates the affinity of the repeat for different nucleotide targets. The combination and order of various repeat types define the genomic target site specificity of a particular TAL effector. It was the deciphering of this TAL effector ‘code’ that recently led to the engineering of designer TAL effector proteins that could act as a vehicle to locate various functionalities to essentially any open region of the chromosomes of plants, bacteria, yeast, flies, and mammalian cells2,3.

So far, activities such as activators, repressors, and nucleases have been demonstrated to be addressable via this powerful system4,5,6. These tools and those that will follow will have applications from efficient genomic editing and gene knockout for manipulation of chromosomes to modulation of specific promoter activities to allow simple and complex metabolic manipulation in various species of cells. GeneArt® Precision TALs Products and Services allow researchers to specify the exact DNA address for delivery of functionality and have specific TAL genes built to perform the function.

GeneArt® Precision TALs are supported by tried and trusted Invitrogen® cloning and transfection reagents such as Gateway® cloning vectors and Lipofectamine® reagents.


1. Boch J and Bonas U (2010) Xanthomonas AvrBs3 family-type III effectors: discovery and function. Annu Rev Phytopathol 48:419–436.

2. Boch J, Scholze H, Schornack S, Landgraf A, Hahn S, Kay S, Lahaye T, Nickstadt A, and Bonas U
(2009) Breaking the code of DNA binding specificity of TAL-type III effectors. Science 326:1509–1512.

3. Moscou MJ and Bogdanove AJ (2009) A simple cipher governs DNA recognition by TAL effectors. Science 326:1501.

4. Li T, Huang S, Zhao X, Wright DA, Carpenter S, Spalding MH, Weeks DP, and Yang B (2011) Modularly assembled designer TAL effector nucleases for targeted gene knockout and gene replacement in eukaryotes. Nucleic Acids Res 39:6315–6325.

5. Scholze H and Boch J (2011) TAL effectors are remote controls for gene activation. Curr Opin Microbiol 14:47–53.

6. Mussolino C and Cathomen T (2012) TALE nucleases: tailored genome engineering made easy. Curr Opin Biotechnol 23:644-650.

For research use only. Not for use in diagnostic procedures.