The mouse cDNA (with added HA tag sequences) is driven by tetracycline response elements (TRE) and a minimal CMV promoter. SV40 poly(A) signal sequences are downstream of the cDNA. The gene will only be expressed in a tetracycline/doxycycline controllable manner if mice carrying this allele are crossed with mice carrying a tTA or rtTA allele. (J:265554)