A simple cipher governs DNA recognition by TAL Effectors

Department of Plant Pathology and Bioinformatics and Computational Biology Program, Iowa State University, Ames, IA 50011, USA.
Science (Impact Factor: 33.61). 10/2009; 326(5959):1501. DOI: 10.1126/science.1178817
Source: PubMed


TAL effectors of plant pathogenic bacteria in the genus Xanthomonas bind host DNA and activate genes that contribute to disease or turn on defense. Target specificity depends on an effector-variable number of typically 34 amino acid repeats, but the mechanism of recognition is not understood. We show that a repeat-variable pair of residues specifies the nucleotides in the target site, one pair to one nucleotide, with no apparent context dependence. Our finding represents a previously unknown mechanism for protein-DNA recognition that explains TAL effector specificity, enables target site prediction, and opens prospects for use of TAL effectors in research and biotechnology.

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Available from: Matthew J Moscou, Mar 11, 2015
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    • "Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049 Karlsruhe, Germany residues. In 2009, it was shown that each of the repeating sequences is able to recognize and bind exactly one nucleotide on the DNA[12,13]. An engineered TALE nuclease was created by fusing the DBD once again to FokI, in these experiments, cloning of a new nuclease was facilitated by adapting the GoldenGate cloning method[14]. "
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    • "and their homologs from Ralstonia solanacearum are transcription factors containing a central DNA-binding domain of tandem repeats composed of 33–35 nearly identical amino acids except for two residues known as repeat-variable diresidues that mediate DNA-binding specificity (Figure 2). TALE proteins are injected into plant cells via a type III secretion system and translocate to the nucleus.767778TALEs bind to the promoters of susceptibility genes as virulence factors or executor R genes as avirulence factors to promote disease or trigger resistance, respectively, by turning on or transactivating downstream genes.798081Engineered "
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    • "These manipulations of the complex eukaryotic genome help researchers understand the function of genes in a given cellular context, explore the mode of gene regulation at the endogenous locus, and, most importantly, model human disease conditions using in vitro cellular models or in vivo model organisms. Since the emergence of designer nucleases based on DNA base recognition by modular protein motifs, such as Zinc Fingers in Zinc Finger Nucleases (ZFNs) [1] [2] [3], as well as TALE domains in transcription activator-like effector nucleases (TALENs) [4] [5], site-specific DNA manipulations in eukaryotic cells have passed a critical efficiency and specificity threshold to enable routine applications in a laboratory. The recently developed, explosively popular CRISPR/Cas9 (clustered regularly interspaced palindromic repeats/CRISPR-associated) genome-engineering system has transformed discovery in this exciting era. "
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