The transgene expresses the carboxy-terminal proteolytic fragment (p25) of human cyclin-dependent kinase 5, regulatory subunit 1, bearing a carboxy-terminal green fluorescent protein (GFP) tag, under control of the tetracycline operator. The purpose of the GFP tag is to differentiate immunologically the transgene-encoded p25 from the endogenous p35 protein. (J:104240)