Difference between revisions of "Part:BBa K782020"

Latest revision as of 22:02, 26 September 2012

10x[TALA] operator_CMV promoter_fLuciferase

• TALA label represents TAL effector 1257 from zebrafish experiments (Sander et al., 2011).
• DNA binding sites for individual TAL effectors are indicated with square brackets [ ].

Introduction

Transcription activation like (TAL) effectors are DNA binding proteins with a high specifity, built from tandem repeats, with near identical seqences, differing only in two amino acids in each repeat called “repeat variable diresidue” (RVD), which determine the specifity for a single nucleotide.(Scholze and Boch, 2011)

We designed our construct with 10 binding sites for TALA, upstream of a CMV promoter (constitutive promoter for expression in mammalian cells). Downstream of the promoter we cloned fLuciferase (firefly luciferase) to function as a reporter.

Figure 1:Schematic representation of our construct.

Characterisation

HEK293T cells were transfected with the 10x[TALA] operator_CMV promoter_fLuciferase reporter and TALA:NLS:KRAB (Figure 2). Tests showed, successful repression of fLuciferase with TAL repressor. Tests showed that tested construct exhibited over 90% repression of the reporter plasmid (Figure 3).

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

Figure 3:Testing repression of reporter luciferase gene. White column is showing constantly expressed reporter (fLuc), blue column is showing repression with TALA:KRAB.

• fLuciferase was contributed by host lab.
• Binding sites for TAL effectors were ordered from IDT.

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.

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

Sequence and Features