Part:BBa_K5267048
P_CMV->MTNR1B->bGH_polyA
Expression of MT2 gene
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21INCOMPATIBLE WITH RFC[21]Illegal BglII site found at 614
Illegal BamHI site found at 1255
Illegal BamHI site found at 1435 - 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
Profile
Name: P_CMV->MTNR1A->bGH_polyA
Base Pairs: 1909bp
Origin: Homo sapiens
Properties: Expression of MT1 gene
Usage and Biology
The melatonin receptors (MTs), specifically MT1 (melatonin receptor type 1) and MT2 (melatonin receptor type 2), are classified under the G protein-coupled receptor (GPCR) family A, with melatonin acting as their endogenous agonist. These receptors are pivotal in the regulation of the circadian rhythm within the human body and are intricately linked to a spectrum of vital physiological processes, including reproductive function, neuronal modulation, and immune system regulation. Furthermore, MTs represent a significant therapeutic target for the amelioration of various pathologies, such as insomnia, affective disorders, and oncological conditions.[1].
Despite the high degree of homology between human MT1 and MT2 receptors, there are considerable differences in their tissue distribution, intracellular signaling mechanisms, and physiological roles. The current dearth of selectivity in melatonin-based pharmaceuticals for either MT1 or MT2 receptors impedes the precision therapy of related disorders. Consequently, the detailed structural elucidation of the MTs agonist binding site is of paramount importance for the development of targeted pharmacotherapeutics.[2]
In light of this, we have engineered a pathway that, upon promoter activation, initiates the synthesis of the MT1 melatonin receptor protein. This strategy is instrumental in the establishment of a cellular assay system designed for the screening of melatonin receptor agonists.(Figure 1)
To achieve the objective of driving the expression of the MT1 melatonin receptor, we strategically selected the CMV promoter, a robust promoter derived from the human Cytomegalovirus (CMV), known for its high transcriptional activity in eukaryotic cells. The CMV promoter has been demonstrated to be highly efficacious in facilitating the expression of lengthy and complex genes within HEK-293T cells.[3] Utilizing the CMV promoter, we initiated the transcription of the MT1 gene within the construct of the gene expression vector, thereby enhancing the expression profile of the MT1 gene. This approach is anticipated to provide a foundation for the development of a cell-based screening platform for melatonin receptor agonists. To substantiate the functionality of the aforementioned constructs, human embryonic kidney 293 cells (HEK293) were co-transfected with expression vectors harboring the newly engineered NanoLuc-reporter genes. 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. At the cellular level, melatonin can affect the activity of calcium channels through its receptors, leading to changes in intracellular calcium concentration. The reporting system is designed to be responsive to oscillations in intracellular Ca2+ concentrations. The optimal configuration of the reporting pathway was ascertained by evaluating and comparing the relative luminescence unit (RLU) expression profiles of the NanoLuc reporter genes, thereby discerning the most efficacious design among the various constructs. Initially, we co-transfected HEK293T cells with an expression vector encoding the NanoLuc reporter gene, followed by the induction of an intracellular calcium ion (Ca2+) response using thapsigargin. Each experimental condition was performed in triplicate, alongside a non-transfected control group lacking NFAT (BBa_K5267049). Upon a 48-hour exposure to thapsigargin, the luminescence intensity of the NanoLuc reporter, expressed in relative light units (RLU), was measured across all experimental groups to evaluate the transcriptional activity evoked by thapsigargin stimulation. Subsequently, the same reporter gene was co-transfected into HEK293T cells, and the intracellular Ca2+ response was provoked by melatonin. The experiments were conducted with three replicates each, and a control group was included, which was not subjected to melatonin stimulation. After a 24-hour melatonin stimulation period, the luminescence intensity of the NanoLuc reporter element, quantified in RLU, was assessed in all experimental groups to determine the transcriptional activity induced by melatonin treatment.
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 1xNFAT promoter with 10 nM thapsigargin resulted in a mean augmentation of the NanoLuc reporter gene expression to a magnitude that was 1.96-fold superior to that ascertained in the absence of thapsigargin induction.
Figure 1. MT1 gene expression pathway.
Special design
Function test
Method
Results
None