When setting up an experiment using lentiviral vectors, a necessary step is to test and compare different promoters.The choice of the promoter is a crucial parameter to design experimental strategies. Two parameters are to be considered:
One of the most determinant element to achieve ideal transgene expression is the promoter. Inconveniently, its activity is subject to many parameters that will make its efficiency variable from one experiment to the next.
GEG-tech offers a large panel of specific and ubiquitous promoters to allow you to find the most relevant promoter(s) for your experimental studies. The choice of the promoter will be done according to the nature of the target cells and the desired level of expression. Once you have defined your criteria, GEG-tech suggests you test several promoters with a reporter construction. This first assay will help you to determine which promoter is the most suited for your project.
As an example, you may have a look at a study we performed to compare vectors expressing the GFP under the control of different ubiquitous promoters in basic cell lines. This study illustrates how the nature of the promoter and of the target cell interact to influence transgene expression and result in a wide range of transgene expressions.
Example 1: Ubiquitous expression
The transgene expression level per cell is influenced by the promoter and the nature of the target cells. The results below illustrate the relationship between these parameters and show that each cell type is specific. We've tested Lenti-ONE™ expressing GFP under the control of 3 different ubiquitous promoters in 7 different cell lines.
INFLUENCE OF THE PROMOTER ON THE TRANSGENE EXPRESSION EFFICIENCY WITH Lenti-ONE™
Influence of the target cell type on the number of transduced cells with 3 Lenti-ONE™ wherein GFP expression is driven by 3 ubiquitous promoters (CMV, PGK or Ubiquitin). Note that:
Influence of the target cell type on the transgene expression level per cell with 3 Lenti-ONE™ wherein GFP expression is driven by 3 ubiquitous promoters (CMV, PGK or Ubiquitin). Note that:
Also note that for a given cell line, the highest number of transduced cells and the highest level of expression per transduced cells are not necessarily obtained with the same promoter.
Example 2: Cell specific expression
In the same approach, if you want to test different specific promoters for your study, you'll have the chance to customize your own Promoter Set and to formulate your request to our On-Demand Services.
Similarly to Promoter Tryout Sets, we propose Envelope Tryout Sets which allow you to find the best envelope to use in your experimental context. These Sets allow you to find the best combination envelope/promoter. Furthermore, if you need non integrating lentiviral vector (Lenti-ONE™ Epi), we also propose the Integrase Set - Non-Integrative mutants to help you choose the best version of Lenti-ONE™ Epi for your research studies. Finally, if you want to test specific combinations envelope/promoter/integrase that are not available, please contact our On-Demand Services.