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Revision as of 17:54, 9 October 2022


LBD-GGGSG-tetR-vp64

This part is an integrated tool for the perception of cortisol stimulation and activates the transcription of the reporter gene.


Usage and Biology

As a glucocorticoid sensor, this part is designed to enter the nucleus upon glucocorticoid stimulation and bind to the TCE promoter to activate downstream transcription. The NR3C1 LBD domain on the N terminus is the ligand binding domain of the glucocorticoid receptor (GR). This LBD domain can translocate the fusion protein into the nucleus upon glucocorticoid stimulation. It also has a transactivating domain 2 (τ2) and an activation function domain 2 (AF2) which activates downstream gene expression.[1] GGGSG linker, owning some flexibility and allowing the proteins on both sides to complete their own independent functions. Tet R in our design provides DNA binding domain tightly binding to the downstream gene, which binds to the TCE promoter (BBa_K4016011) consisting of seven direct 19-bp Tet operator sequence (Teto) repeats. VP64 is a transcriptional activator composed of four tandem copies of VP16 connected with glycine-serine (GS) linkers. 

Figure1.Schematic figure of (BBa_K4414028) and (BBa_K4414041).

Sequecing

The plasmid was sequenced correct.

Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    COMPATIBLE WITH RFC[1000]



Functional test

To test the ability of this part to respond to glucocorticoids, HEK-293T cells were co-transfected with plasmids encoding both LBD-1*GSlinker-Tet R-VP64(BBa_K4414028) and TCE-SEAP(BBa_K4414041).

Method

Cells were treated with 0 or 100 nm Glucocorticoids 6h post-transfection. Cells without glucocorticoid treatment were used as control. Culture medium was collected at 24h post glucocorticoids treatment. SEAP activity was measured according to a published protocol. [2]

Figure2.Schematic representation of the experimental process of validation for (BBa_K4414028) and (BBa_K4414041).


Result

Results showed similar SEAP expression in glucocorticoid-treated cells compared to the non-treated control (1.78 folds).

Figure3.Glucocorticoid-stimulated transcriptional activation of SEAP mediated by (BBa_K4414028).

Reference

[1].Weikum ER, Knuesel MT, Ortlund EA, Yamamoto KR. Glucocorticoid receptor control of transcription: precision and plasticity via allostery. Nat Rev Mol Cell Biol. 2017 Mar;18(3):159-174. doi: 10.1038/nrm.2016.152. Epub 2017 Jan 5. PMID: 28053348; PMCID: PMC6257982.

[2].Shao J, Qiu X, Xie M. Engineering Mammalian Cells to Control Glucose Homeostasis. Methods Mol Biol. 2021;2312:35-57. doi: 10.1007/978-1-0716-1441-9_3. PMID: 34228283.