Practice question

Tissue specific conditional knockout exploits Cre expression under cell type specific promoter. Floxed target gene remains intact in all cells. Cre recombinase driven by neuron specific enolase or Synapsin-1 promoter is transcribed only in neurons, so loxP flanked exon excision occurs exclusively in neuronal lineage, leaving other tissues wild type. This spatial control avoids lethality of global deletion. Inducible systems add temporal regulation, but neuron restricted pattern directly indicates use of neuron specific regulatory element controlling Cre recombinase expression cassette.