Part:BBa_K4414043

LBD-GSG-NES-GSG-EGFP

This composite part consists of a C-Terminal EGFP (Part:BBa_K1123017) and an N-Terminal GR LBD (Part:BBa_K4414000) domain fused with a NES (Part:BBa_K4414003). There is a GSG linker between every two genes. It is designed to sense glucocorticoids and locate glucocorticoid receptor (GR) in cells.

Usage and Biology

The EGFP on the C-Terminal locates glucocorticoid reporter (GR). The GR LBD domain on the N-Terminal is a 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 trans-activating domain 2 (τ2) and an activation function domain 2 (AF2) which activates downstream gene expression(Weikum et al., 2017). The NES is a nuclear export signal. To ensure that domains work properly, GSG linker is designed between every two genes.

Figure 1.Schematic figure of BBa_K4414043

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]

Fuctional test

Method

To test the ability of this part to respond to glucocorticoids, HEK-293T cells were co-transfected with plasmids encoding BBa_K4414043. Cells were treated with 100 nM Glucocorticoids 6 h post-transfection. Cells without glucocorticoid treatment were used as control. The fluorescence intensity of cells was observed 24 h after posting glucocorticoids treatment.

Result

Fluorescence images are shown below, which indicates that under the action of NES, glucocorticoids can bind to LBD and enter the nucleus. This provides a basic direction of thinking for our experiments.

Figure 2.The picture on the left is Bright-field cell diagram, the picture in the middle is fluorescence diagram, and the picture on the right is merge diagram.

Reference

1. Weikum, E. R., Knuesel, M. T., Ortlund, E. A., & Yamamoto, K. R. (2017). Glucocorticoid receptor control of transcription: precision and plasticity via allostery. Nature reviews. Molecular cell biology, 18(3), 159–174. https://doi.org/10.1038/nrm.2016.152