Difference between revisions of "Part:BBa K782008"

(Characterization)
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__NOTOC__
 
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<partinfo>BBa_K782008 short</partinfo>
 
<partinfo>BBa_K782008 short</partinfo>
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TALA label represents TAL efector 1257 from zebrafish experiments (Sander et al., 2011)
  
 
==Introduction==
 
==Introduction==
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We designed TALE-based repressors for specific gene repression, by fusing TAL effectors with the KRAB transcriptional repression domain downstream of the CMV promoter. KRAB was placed on the C-terminal ends of the TALE DNA-binding domain (Figure 1)
 
We designed TALE-based repressors for specific gene repression, by fusing TAL effectors with the KRAB transcriptional repression domain downstream of the CMV promoter. KRAB was placed on the C-terminal ends of the TALE DNA-binding domain (Figure 1)
  
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[[Image:SVN_12_TALA_KRAB.png]]
  
 
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'''Figure 1:''' Schematic representation of the repressor construct
Figure 1: Schematic representation of the repressor construct
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==Characterization==
 
==Characterization==
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[[Image:Luciferaza_reporter.png | 300 px]]
 
[[Image:Luciferaza_reporter.png | 300 px]]
  
Figure 2: Schematic representation of repression experiments. A: in the absence of a TAL repressor, the reporter gene is constituitively expressed. B: when a TAL repressor is present, it binds to its respective binding site upstream of the CMV promoter and represses transcription of the reporter gene with the KRAB domain.
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'''Figure 2:''' Schematic representation of repression experiments. A: in the absence of a TAL repressor, the reporter gene is constituitively expressed. B: when a TAL repressor is present, it binds to its respective binding site upstream of the CMV promoter and represses transcription of the reporter gene with the KRAB domain.
  
  
  
  
Figure 3:Testing repression of reporter gene transcription by addition of TAL repressors
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'''Figure 3:'''Testing repression of reporter gene transcription by addition of TAL repressors
  
  
 
   
 
   
  
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==References==
  
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Sander, J. D., Cade, L., Khayter, C., Reyon, D., Peterson, R. T., Joung, J. K., and Yeh, J.-R. J. (2011) Targeted gene disruption in somatic zebrafish cells using engineered TALENs. Nature Biotechnology 29, 697–698 [online] http://www.nature.com/doifinder/10.1038/nbt.1934 (Accessed August 7, 2011).
  
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Urrutia R. (2003)  KRAB-containing zinc-finger repressor proteins. Genome Biology 4:231
  
 
<!-- Add more about the biology of this part here
 
<!-- Add more about the biology of this part here

Revision as of 17:22, 24 September 2012

TALA:NLS:KRAB

TALA label represents TAL efector 1257 from zebrafish experiments (Sander et al., 2011)

Introduction

TAL effectors (TALEs) are bacterial plant pathogen transcription factors, that bind to DNA by specifically recognizing one base pair with a single tandem repeat in their DNA-binding domain. A tandem TALE repeat contains 33 to 35 amino acids, where the 12th and 13th amino acid, called a “repeat variable diresidue” (RVD), are responsible for specific interactions with the corresponding base pair.

The Kruppel-associated box (KRAB) domain is a transcriptional repressor module commonly found in eukaryotic zinc finger proteins. When KRAB containing protein binds to corresponding DNA sequence it triggers recruitment of Kap1 corepressor. KRAB domain directly interacts with a RING-B-box-coiled-coil (RBCC) domain of corepressor protein Kap1. When Kap1 binds to a KRAB domain it functions as a scaffold and starts to recruits heterocromatin protein 1 isoforms (HP1-α HP1-β HP1-γ), histone deacetylases (HDACs) and Setdb1. This complex forms facultative heterocromatin environment on a target promoter and mediates transcriptional repression (Urrutia, 2003).

We designed TALE-based repressors for specific gene repression, by fusing TAL effectors with the KRAB transcriptional repression domain downstream of the CMV promoter. KRAB was placed on the C-terminal ends of the TALE DNA-binding domain (Figure 1)

SVN 12 TALA KRAB.png

Figure 1: Schematic representation of the repressor construct

Characterization

HEK293T cells were cotransfected with TAL repressor constructs, constituively expressed by the CMV promoter, and firefly luciferase reporter plasmids (Figure 2), containing 10 binding sites for the designated TAL repressor upstream of the CMV promoter. All experiments were executed in 3 biological replicates and repeated over 3 times with similar results.Tests showed that tested construct exhibited over 90% repression of the reporter plasmid (Figure 3).

Luciferaza reporter.png

Figure 2: Schematic representation of repression experiments. A: in the absence of a TAL repressor, the reporter gene is constituitively expressed. B: when a TAL repressor is present, it binds to its respective binding site upstream of the CMV promoter and represses transcription of the reporter gene with the KRAB domain.



Figure 3:Testing repression of reporter gene transcription by addition of TAL repressors



References

Sander, J. D., Cade, L., Khayter, C., Reyon, D., Peterson, R. T., Joung, J. K., and Yeh, J.-R. J. (2011) Targeted gene disruption in somatic zebrafish cells using engineered TALENs. Nature Biotechnology 29, 697–698 [online] http://www.nature.com/doifinder/10.1038/nbt.1934 (Accessed August 7, 2011).

Urrutia R. (2003) KRAB-containing zinc-finger repressor proteins. Genome Biology 4:231

Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    INCOMPATIBLE WITH RFC[21]
    Illegal BamHI site found at 2439
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    INCOMPATIBLE WITH RFC[1000]
    Illegal BsaI.rc site found at 2805
    Illegal SapI.rc site found at 2769