Patent ID: 8222478

Claim:
A transgenic non-human mammal that conditionally overexpresses myostatin (Mst) when provided with a control factor selected from tetracycline and doxycycline, said transgenic non-human mammal having a genome that comprises a conditional bicistronic myostatin expression nucleic acid construct selected from the group of nucleic acid constructs consisting of: a) i) polyA-green fluorescence protein (EGFP)/internal ribosome entry site (IRES)-Mst/hemagglutinin (HA)-tetracycline response element (TRE)//MCK-rtTA/blue fluorescence protein (BFP)-polyA, ii) polyA-BFP/rtTA-MCK//TRE-HA/Mst-IRES/EGFP-polyA, iii) TRE-HA/Mst-IRES/EGFP-polyA//MCK-rtTA/BFP-polyA, iv) MCK-rtTA/BFP-polyA//TRE-HA/Mst-IRES/EGFP-polyA, v) TRE-HA/Mst-IRES/EGFP-polyA//polyA-BFP/rtTA-MCK, or vi) MCK-rtTA/BFP-polyA//polyA-EGFP/IRES-Mst/HA-TRE; b) any one of the constructs of a) lacking a HA tag; c) any one of the constructs of a) lacking an IRES/EGFP or EGFP/IRES; and d) any one of the constructs of a) lacking a BFP fusion to the rtTA sequence; where MCK is a promoter selected from muscle specific creatine kinase, MCK-3E, and troponin I; wherein Mst expression is inducible by administration of said control factor; and wherein said transgenic non-human mammal overexpresses Mst in response to administration of said control factor to said transgenic non-human mammal, whereby, following said administration of said control factor, said Mst overexpression is detectable, and said transgenic non-human mammal has decreased muscle mass as compared to control wild-type mammals.