Difference between revisions of "Part:BBa K2295001"
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<h2>Overview</h2>
 
<h2>Overview</h2>
 
This part is a cAMP dependent promoter. Being one of the main downstream signaling pathways of Gs coupled GPCRs (G protein coupled receptors), this BioBrick supports the combination with a wide range of other parts. The iGEM BioBrick library already contains several Gs coupled GPCRs. Depending on the GPCR, different inputs can be used for ligand dependent gene expression.
 
This part is a cAMP dependent promoter. Being one of the main downstream signaling pathways of Gs coupled GPCRs (G protein coupled receptors), this BioBrick supports the combination with a wide range of other parts. The iGEM BioBrick library already contains several Gs coupled GPCRs. Depending on the GPCR, different inputs can be used for ligand dependent gene expression.
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<h2>Characterization of the CRE Promoter</h2>
 
<h2>Characterization of the CRE Promoter</h2>
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[[Image:T-FREIBURG-CRE_Results-50pc.png|900px|thumb|center|'''Figure 1:''' Flow cytometry of hypoxia response element promoter analysis. a)</b> Jurkat cells stably transduced with 4xCRE-pTal:eCFP were incubated 24 h in pH adjusted RPMI 1640. <b>b)</b> The experiment was repeated inducing with Forskolin (10 µM) and IBMX (10 µM). <b>c)</b> and <b>d)</b> HEK293T cells stably transduced with 4xCRE-pTal:eCFP with and without transient TDAG8 were induced similarly to <b>a)</b> and <b>b)</b>. Results show the represent the amount of eCFP positive cells <b>c)</b> and the <b>d)</b> mean fluorescence intensity. All data points are mean values of triplicates, error bars represent standard deviation. Significant differences in a) and b) were determined using ANOVA, for c) and d) significant differences were determined using one-tailed student’s t-test (Excel 2017); * p < 0.05, ** p < 0.01, *** p < 0.001, non-significant differences are not marked.]]
 
[[Image:T-FREIBURG-CRE_Results-50pc.png|900px|thumb|center|'''Figure 1:''' Flow cytometry of hypoxia response element promoter analysis. a)</b> Jurkat cells stably transduced with 4xCRE-pTal:eCFP were incubated 24 h in pH adjusted RPMI 1640. <b>b)</b> The experiment was repeated inducing with Forskolin (10 µM) and IBMX (10 µM). <b>c)</b> and <b>d)</b> HEK293T cells stably transduced with 4xCRE-pTal:eCFP with and without transient TDAG8 were induced similarly to <b>a)</b> and <b>b)</b>. Results show the represent the amount of eCFP positive cells <b>c)</b> and the <b>d)</b> mean fluorescence intensity. All data points are mean values of triplicates, error bars represent standard deviation. Significant differences in a) and b) were determined using ANOVA, for c) and d) significant differences were determined using one-tailed student’s t-test (Excel 2017); * p < 0.05, ** p < 0.01, *** p < 0.001, non-significant differences are not marked.]]
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<h2>Multiple Enhancer Elements</h2>
 
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Increasing the amount of enhancer elements results in an upregulation transcription downstream of the minimal promoter. This allows highly specific tuning to target cell types. We thereby create the chance for other iGEM teams to use our BioBricks and adjust them to their individual needs. This can be easily done by using compatible end assembly, which is possible due to a BglII restriction site contained in BBa_K2295003.
 
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Revision as of 02:32, 31 October 2017


CRE (cAMP response element)

Overview

This part is a cAMP dependent promoter. Being one of the main downstream signaling pathways of Gs coupled GPCRs (G protein coupled receptors), this BioBrick supports the combination with a wide range of other parts. The iGEM BioBrick library already contains several Gs coupled GPCRs. Depending on the GPCR, different inputs can be used for ligand dependent gene expression.

Characterization of the CRE Promoter

The cAMP response element-containing promoter (pCRE), which is pH responsive, was characterized in vitro in Jurkat and HEK293T cell lines. For this purpose, the pH of the media had to be adjusted.

Promoter characterization

In order to characterize the CRE promoter, stably transduced HEK293T and Jurkat lines were created expressing eCFP under a minimal promoter with multiple CRE sites. Induction was performed with pH adjusted media. Constitutively expressed mCherry was used as transduction marker. For analysis in HEK293T, PEI transfection of the pH receptor TDAG8, which is not expressed in these cells, was performed. (Ausländer et al., 2014). To generate a high expression by activating the signaling cascade downstream of the receptor, the stable cell lines were induced with forskolin and IBMX. Forskolin activates the cAMP-producing enzyme adenylyl cyclase and IBMX inhibits cAMP-hydrolyzing phosphodiesterases (Bittinger et al., 2004). Fluorescence was measured by flow cytometry after 24 h of treatment (Fig. 1).


Figure 1: Flow cytometry of hypoxia response element promoter analysis. a)</b> Jurkat cells stably transduced with 4xCRE-pTal:eCFP were incubated 24 h in pH adjusted RPMI 1640. b) The experiment was repeated inducing with Forskolin (10 µM) and IBMX (10 µM). c) and d) HEK293T cells stably transduced with 4xCRE-pTal:eCFP with and without transient TDAG8 were induced similarly to a) and b). Results show the represent the amount of eCFP positive cells c) and the d) mean fluorescence intensity. All data points are mean values of triplicates, error bars represent standard deviation. Significant differences in a) and b) were determined using ANOVA, for c) and d) significant differences were determined using one-tailed student’s t-test (Excel 2017); * p < 0.05, ** p < 0.01, *** p < 0.001, non-significant differences are not marked.


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]