Mpv17<sup>-/-</sup> mouse liver mitochondria have significantly reduced levels of two precursors of DNA synthesis, dGTP and dTTP.

<p>The abundance of dNTPs was determined by means of an extension assay after extraction of nucleotides from liver (<b>A</b>), kidney (<b>B</b>) or brain (<b>C</b>) of <i>Mpv17</i><sup><i>+/+</i></sup> and <i>Mpv17</i><sup><i>-/-</i></sup> mice (see <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1005779#sec010" target="_blank">Methods</a>). All mice (n = 5) were sacrificed between 8 and 10 weeks of age. P values were obtained using Mann-Whitney test (* P<0.05, NS, not significant P>0.05).</p>