Part:BBa_K5267008
Pmin_5*NFAT promoter
Transpose and respond to calcium ion signals Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
Profile
Name: Pmin_5*NFAT promoter
Base Pairs: 191bp
Origin: Homo sapiens
Properties: Transpose and respond to calcium ion signals
Usage and Biology
Nuclear factor of activated T cells (NFAT) was first identified over two decades ago as a major stimulation-responsive DNA-binding factor and transcriptional regulator in T cells. NFATs are a family of Ca²⁺-dependent transcription factors that play a central role in the morphogenesis, development, and physiological activities of various cell types and organ systems.
NFAT is widely expressed across different animal tissues and cell types, serving as a key regulatory point in multiple intracellular signal transduction pathways. It plays crucial roles in the immune system, nervous system development, axon growth, and various nervous system diseases. In this project, NFAT is utilized to monitor the effects of increases in intracellular Ca²⁺ concentrations indirectly [1].
Special design
To non-invasively assess the impact of elevated intracellular calcium ion (Ca²⁺) concentrations, we developed a series of Ca²⁺-inducible NanoLuc reporters based on the Ca²⁺-dependent activation of dimeric NFAT, as illustrated in Figure 1[2]. These reporters incorporate a varying number of tandem repeats (1×, 5×, 6×, and 7×) of a pseudo-palindromic NFAT response element (NFAT-RE) derived from the interleukin-4 (IL-4) promoter sequence (5′-TACATTGGAAAATTTTAT-3′) with minimal CMV promoter (parts:BBa_K5267049). This setup is anticipated to drive the transcription of the NanoLuc reporter gene when NFAT is dephosphorylated due to the significantly increased intracellular Ca²⁺ concentrations (Figure 1).
Thapsigargin (TG) is a known ER stress inducer that increases intracellular calcium (Ca²⁺) concentration by inhibiting the calcium atpase (SERCA pump) in the ER. This increased calcium concentration can activate a variety of cell signaling pathways, including the NFAT (nuclear factor of activated T cells) pathway, thereby analyzing the sensitivity and activation threshold of the NFAT pathway.
We introduced the expression vectors encoding the novel NanoLuc-reporter constructs into HEK293T cells via co-transfection, followed by the application of thapsigargin to elicit an intracellular calcium ion (Ca²⁺) response. The experimental paradigm encompassed three replicate experiments alongside a non-transfected control group (BBa_K5267049). Subsequent to a 48-hour exposure to thapsigargin, the luminescence intensity of the reporter element NanoLuc (measured as relative light units, RLU) was quantified across all experimental cohorts to assess the transcriptional activity induced by the treatment.
Top:
[1] M. R. Müller and A. Rao, “NFAT, immunity and cancer: a transcription factor comes of age,” Nat. Rev. Immunol., vol. 10, no. 9, pp. 645–656, Sep. 2010, doi: 10.1038/nri2818.
Figure 1. Schematic representation showing the construction of a pseudo-palindromic NFAT-response element (RE)-directed nanoluciferase(Nanoluc) reporter system.
Function test
Method
Result
Figure 2. NFAT activation in response to calcium ion signaling.
HEK-293T cells were transfected with plasmids containing different promoters with 1×/5×/6×/7×NFAT elements respectively. Data are mean±SD of NanoLuc expression levels measured at 48 h after thapsigargin stimulation (n = 3 independent experiments).Upon a 48-hour incubation period, stimulation of the NFAT promoter with 10 nM thapsigargin resulted in a mean augmentation of the NanoLuc reporter gene expression to a magnitude that was 7.18-fold superior to that ascertained in the absence of thapsigargin induction.
Nluc expression increase with time could be detected in cells transfected with pNC100(PNFAT_5-IgK-Nluc) treated with Thapsigargin (10nM). Thapsigargin stimulation less than 1nM could not activate Nluc expression downstream of 5×NFAT (Figure.3).
Figure.3 Step-response dynamics of translated cells under thapsigargin treatment. HEK293T cells were transfected with pNC100(PNFAT_5-IgK-Nluc).
Cells were treated with either DMSO or thapsigargin 6 hours post transcription. Data represents mean±SD of nanoluc expression levels measured at 24 h after melatonin stimulation (n = 3 independent experiments).
Sequence
ggagtacattggaaaattttatacacgttctagctacattggaaaattttatacacgttctagctacattggaaaatttt
atacacgttctagctacattggaaaattttatacacgttctagctacattggaaaattttatacacgttagaccctagag
ggtatataatggaagctcgacttccagtact
Reference
[2] W. Zhang, T. Takahara, T. Achiha, H. Shibata, and M. Maki, “Nanoluciferase Reporter Gene System Directed by Tandemly Repeated Pseudo-Palindromic NFAT-Response Elements Facilitates Analysis of Biological Endpoint Effects of Cellular Ca2+ Mobilization,” Int. J. Mol. Sci., vol. 19, no. 2, p. 605, Feb. 2018, doi: 10.3390/ijms19020605.
[3] K. A. Strait, P. K. Stricklett, R. M. Kohan, and D. E. Kohan, “Identification of Two Nuclear Factor of Activated T-cells (NFAT)-response Elements in the 5′-Upstream Regulatory Region of the ET-1 Promoter,” J. Biol. Chem., vol. 285, no. 37, pp. 28520–28528, Sep. 2010, doi: 10.1074/jbc.M110.153189.
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