The targeting cassette consisting of a SA.lox.Neo/Stop.lox-PDGFRaK.T2A.Flp cassette replaced the exons 2-4 of the endogenous Pdgfra gene. The PDGFRaK is a mouse Pdgfra gene cDNA with a point mutation (D842V) renders it constitutively active. Cre-mediated recombination removed lox.Neo/Stop.lox cassette from Pdgfratm1(flpo)Leol enabling the expression of the constitutively active Pdgfra gene with a point mutation (D842V) and the flpo recombinase. (J:306160)