A Cre-dependent lentiviral vector for neuron subtype-specific expression of large proteins

Lentiviral vectors are powerful tools for long-term expression of large genes in the mammalian brain, but the palette of lentiviral tools available for targeting specific cell subpopulations is restricted. We describe a lentiviral vector for neuronal subtype-specific expression in Cre mouse lines. Combining a Cre-dependent flip excision switch with a GFP and a 2A self-cleaving peptide, it enables identification of living neurons expressing a gene of interest using fluorescence. We validated this vector by targeting neocortical interneuron types and midbrain dopaminergic neurons. Gene expression occurred exclusively in Cre-expressing neurons without altering their basic electrophysiological properties. This system has been designed to be flexible and easy to modify in order to target expression of any gene of interest in any cell subtype.