Generation of a mouse model with inducible expression of I-1c. A, DTG mice were generated using the Tet-off system. TG1 drives expression of the tetracycline-regulated transactivator (tTA) by using the traditional α-myosin heavy chain promoter (α-MHCp). TG2 drives I-1c expression, using the attenuated α-MHCp, which is only active in the absence of Dox. B, Immunoblot analysis, after trichloroacetic acid precipitation of ≈400 mg of tissue, confirmed the validity of the system. DTG mice expressed I-1c at 1.65-fold of endogenous I-1 (WT, n=3; DTG, n=3) on Dox withdrawal for 8 weeks (left blot), whereas I-1c expression was suppressed in the presence of Dox (right blot). Single transgenic I-1c (TG2) mice did not express I-1c either in the presence (right blot) or absence of Dox (left blot). Dotted lines represent different blots. C, Immunoblot analysis for SERCA2a and PLN revealed that Dox administration did not have any off-target effects. Calsequestrin (CSQ) was used as a loading control (WT, n=4; DTG, n=4).