Figure 5: Spreading of heterochromatin outward from cenH.

(a) Fluorescent reporters used in the experiment. Cells with Kint2::YFP (EcoRV)::mCherry are shown on the left in all panels; Kint2::mCherry (EcoRV)::YFP cells are shown on the right. (b) YFP and mCherry fluorescence was measured by microscopy at the indicated time points following the re-introduction of clr4⁺ examining >1,000 cells for each data point. Some uncertainty for the initial timepoint, due to the difficulty in counting germinating spores, is indicated by dashed lines. Histograms for the fluorescence distributions are shown in Supplementary Fig. 2. (c-h) Representative images. (c,d) At the second division following spore germination, the vast majority of clr4⁺ cells express both reporters. (e,f) As cells divide (generation 5), silencing of the reporter at Kint2 (whether Kint2::YFP on the left or Kint2::mCherry on the right) precedes silencing of the reporter at (EcoRV). (d,f) Generation 7. Scale bars, 2 μm.