Figure 4.

¹⁵N fractional abundance decay rates in neuronal versus glial nuclei. (A) FACS sorting of brain nuclei. Brain nuclei were purified and labeled with a fluorescent marker for neuronal nuclei (NeuN), and sorted for NeuN positive and negative populations. Plotted is a scatter plot of representative sorted events, with positive (green) and negative (red) sorted populations highlighted. (B) ¹⁵N fractional abundance decay of Nup205 in neurons versus glia. Elution profile MS1 traces, as described earlier, are plotted for the same peptide from Nup205, originating from neuron-enriched (left) and glial-enriched (right) sorted nuclei from a 1-year post-chase rat. (C) ¹⁵N fractional abundance decay of Nups in neurons versus glia. Average ¹⁵N fractional abundance for each indicated Nup was determined from multiple peptides from the same neuron-enriched (orange) and glial-enriched (grey) nuclei described in B. (D) Histone H3.1 stability. ¹⁵N fractional abundance was determined for the single unique H3.1 peptide at 0, 4, 6, 9, and 12 months post-chase from multiple animals (orange), and plotted against peptides from the same time points which were common to all histone H3 variants (grey). (E) Histone H3.1 in neurons versus glia. ¹⁵N fractional abundance was determined for the single unique H3.1 peptide at 0, 4, 6, 9, and 12 months post-chase from neuron-enriched (orange) and glial-enriched (grey) sorted nuclei, and plotted over time. Note: we did not observe any peptides for glia 9-months post-chase. All error bars are plotted as a standard deviation. See also Figure S4.