But Larsen has found that stem cells deliberately break their own DNA by recruiting caspase-3 and CAD. This act of self-harm switches on important genes that are needed for differentiation; without it, the generalist cells can't specialise. This is an entirely new way of activating genes and it appears to be both important and widespread. [...] The myoblasts need these breaks to produce muscle fibres and to create the breaks, they rely on caspase-3 and its ability to activate CAD. Larsen managed to block the development of muscle fibres by dousing myoblasts with chemicals that neutralise caspase-3. The same thing happened if he used cells with mutant versions of CAD, which couldn't be activated. In both cases, the cells failed to show any signs of broken DNA.
Tuesday, February 16, 2010
This seems to be all over the news this morning, but in case it was missed: researchers at the OHRI, led by Lynn Megeney, have found that caspase-3 induced DNA damage is required for differentiation into muscle fibre. As usual, Ed Yong at Not Exactly Rocket Science has a great summary of the PNAS paper and analysis.