Homozygous <i>Bmal1</i>-KO mice are arrhythmic.

<p>Representative wheel-running activity charts (actograms) from <i>Bmal1</i> (+/+), (+/−) and (−/−) animals. Every horizontal line represents 2 days of activity, with subsequent days plotted to the right of and below the previous day. Vertical deflections from the horizontal represent 10 minute bins in which wheel revolutions were detected, with the height of the deflection being proportional to the number of revolutions. The animals were housed in a light/dark cycle for the first 4 weeks (darkness indicated by grey shading) and were then transferred into constant darkness for another 4 weeks. Wildtype (left) and heterozygous (middle) animals had normal circadian patterns of activity in both the light/dark cycle as well as in constant darkness. The <i>Bmal1</i>-KO mice were arrhythmic throughout. Animals in this circadian activity assessment were different than those used in the subsequent proliferation/survival experiments.