Reporter Knockin mouse models are genetically engineered mice that contain reporter genes eg LacZ, GFP, and RFP inserted at a specific genomic location. These reporters can replace a gene of interest, can be fused to the target protein, or in its 3'UTR. The expression of the reporter tag can conditional, where the expression is controlled by treatment or universal. The reporter expression can be made tissue specific by engineering it to be under the regulation of endogenous tissue-specific promoter or engineered to be expressed under the promoter of a housing-keeping gene like B-actin for universal expression.

These models are useful for gene expression monitoring, analysis of gene expression patterns, cell lineage analysis, drug screening, and biomarker discovery.