Exploiting promoters and enhancers of cell-type specific enzymes, like those for dopamine synthesis, allows for cell-type specific gene expression.

“each cell type is defined by its job just as in many cases cases we are defined by our jobs uh and and this is a a critical thing because a professional dopamine producing cell is going to have by its dopamine enzyme encoding genes it's going to have promoters or enhancers that are that dictate in this cell type this gene will be active”