Say you have a transgenic mouse who has been genetically modified to express eGFP where ever Protein X is expressed. What events might cause eGFP not to be expressed in a cell, when you are certain that Protein X is expressed. For example, say you are looking at two cells fluorescently stained…
1) Positive for eGFP and Positive for anti-Protein X
2) Negative for eGFP and Positive for anti-Protein X
I suppose that if the GFP protein was mis-folded, it would prevent the eGFP signal, however I would not expect this to happen too often. Any other ideas?
I don’t think, that GFP misfolding would occur. You could have some other substance, which would adsorb the emitted light, that’s used sometimes, but for protein-protein interaction research. But I don’t think, that something like that occurred in the cell naturally 🙂