TAL effector: Difference between revisions
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<br>[[Image:sanjana.png|left|400px|thumb|]]<br> | <br>[[Image:sanjana.png|left|400px|thumb|Fig.1]]<br> | ||
'''Figure 1''': Natural structure of TALEs derived from Xanthomonas sp. Each DNA-binding module consists of 34 amino acids, where the RVDs in the 12th and 13th amino acid positions of each repeat specify the DNA base being targeted according to the cipher NG = T, HD = C, NI = A, and NN = G or A. The DNA-binding modules are flanked by nonrepetitive N and C termini, which carry the translocation, nuclear localization (NLS) and transcription activation (AD) domains. A cryptic signal within the N terminus specifies a thymine as the first base of the target site.<ref> PMID:022223736 </ref> | '''Figure 1''': Natural structure of TALEs derived from Xanthomonas sp. Each DNA-binding module consists of 34 amino acids, where the RVDs in the 12th and 13th amino acid positions of each repeat specify the DNA base being targeted according to the cipher NG = T, HD = C, NI = A, and NN = G or A. The DNA-binding modules are flanked by nonrepetitive N and C termini, which carry the translocation, nuclear localization (NLS) and transcription activation (AD) domains. A cryptic signal within the N terminus specifies a thymine as the first base of the target site.<ref> PMID:022223736 </ref> | ||
<br>[[Image:Mak_An.png|right|500px|thumb|]]<br> | <br>[[Image:Mak_An.png|right|500px|thumb|Fig.2]]<br> | ||
'''Figure 2''': Domain organization of PthXo1 and structure of a single TAL effector repeat | '''Figure 2''': Domain organization of PthXo1 and structure of a single TAL effector repeat | ||
TAL effectors contain N-terminal signals for bacterial type III secretion, tandem repeats that specify the target nucleotide sequence, nuclear localization signals, and a C-terminal region that is required for transcriptional activation. PthXo1 contains 23.5 canonical repeats (color coded to match Figure 2) that contact the DNA target found in the promoter of the rice Os8N3 gene (17). Blue bases correspond to positions in the target where the match between protein and DNA differs from the optimal match specified by the recognition code (3,4). Arrows indicate the start and end of the crystallized protein construct. In the structure, repeats 22 to 23.5 are poorly ordered, as are the C-termini of the two N-terminal cryptic repeats. The sequence and structure of a representative repeat (#14) is shown; RVD residues (HD) that recognize cytosine are red.<ref> PMID:22222791 </ref> | TAL effectors contain N-terminal signals for bacterial type III secretion, tandem repeats that specify the target nucleotide sequence, nuclear localization signals, and a C-terminal region that is required for transcriptional activation. PthXo1 contains 23.5 canonical repeats (color coded to match Figure 2) that contact the DNA target found in the promoter of the rice Os8N3 gene (17). Blue bases correspond to positions in the target where the match between protein and DNA differs from the optimal match specified by the recognition code (3,4). Arrows indicate the start and end of the crystallized protein construct. In the structure, repeats 22 to 23.5 are poorly ordered, as are the C-termini of the two N-terminal cryptic repeats. The sequence and structure of a representative repeat (#14) is shown; RVD residues (HD) that recognize cytosine are red.<ref> PMID:22222791 </ref> | ||
==Engineering== | ==Engineering== | ||
<br>[[Image:iGEM.png]]<br> | <br>[[Image:iGEM.png|left|500px|thumb|Fig.3]]<br> | ||
'''Figure 3''': Based on the RVD the construction of a so called GATE Assembly kit was performed by the iGem 2012 Team from Freiburg University. | '''Figure 3''': Based on the RVD the construction of a so called GATE Assembly kit was performed by the iGem 2012 Team from Freiburg University. | ||
<ref> http://2012.igem.org/Team:Freiburg/Project/Tal </ref> | <ref> http://2012.igem.org/Team:Freiburg/Project/Tal </ref> | ||
