Drug interactions gene expression systems

For in vivo studies, animal models are set up and how the target is involved in the disease is analyzed. One such model is the use of knockout or transgenic mice (Exhibit 2.8). It should be borne in mind, however, that there are differences between humans and animals in terms of gene expression, functional characteristics, and biochemical reactions. Nevertheless, animal models are important for the evaluation of drug-target interactions in a living system. 

Figure 4 Architecture of three-hybrid screens, (a) The classic, small-molecule-based, three-hybrid platform is shown. The three components of this systems are a DNA-binding protein fused to a known drug-binding domain (X), a bifunctional small molecule that binds X on one end and displays a query "bait" on the other, and a library of possible "prey" proteins (V) expressed as fusions to transcriptional activation domains. Assembly of the ternary complex recruits the activation domain to the promoter and initiates reporter gene expression. A partial list of examples is shown in the inset boxes because of space constraints, some relevant systems are absent, (b) The RNA-based, three-hybrid is assembled in a similar fashion except that the bifunctional ligand is an RNA molecule. The complex between the MS2 RNA and the MS2-coat protein is typically used as the anchoring interaction.

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