Shutting down a gene-regulating protein boosts mouse muscle mass and exercise endurance, as well as insulin sensitivity.

Johan Auwerx at the Swiss Federal Institute of Technology Lausanne (EPFL) and his colleagues deleted the gene that encodes NCoR in the muscles of mice. The mutant animals ran for a longer period of time and over a greater distance than normal mice. Their muscles also contained higher numbers of power-generating cellular organelles called mitochondria.

In a separate study, Jerrold Olefsky at the University of California, San Diego, and his co-workers, including Auwerx, deleted the gene in fat cells in mice. The authors found that the animals became more obese than did normal mice when fed a high-fat diet, but had higher insulin sensitivity in liver, muscle and fat tissues.

Gene-expression analysis of the mutant mice revealed that the most upregulated set of genes was associated with the PPAR-γ signalling pathway, which is involved in fat-cell development and insulin sensitivity.

Cell 147, 827–839; (2011)

Cell 147, 815–826; (2011)