Figure 3.

Persistent DNA damage and mitotic errors in aged cells. Whole life span imaging of cells expressing the indicated fluorescent proteins. (A,B) Rfa1-mCherry foci in divisions leading up to cell death. Rfa1-mCherry foci that did not resolve within 1 h after bud formation or persisted through anaphase were counted as persistent (A39864). The arrowhead in B highlights a nuclear flare. (C) Rad52-mCherry foci that persist for >20 min in divisions leading up to cell death (A39865). (D) Formation of a tripolar spindle that results in chromosome missegregation. Spindle pole bodies were visualized using a Spc42-mCherrry fusion, and chromosome I was visualized using a GFP dot (LacO/LacI-GFP; A37624) (see the Supplemental Material). (E) Quantification of chromosome missegregation during the first and last cell divisions of a yeast cell's life. (F–H) Formation of more than two nuclear compartments in telophase during the cell divisions leading up to cell death (A36566). Note that the data shown in H are the same as in Figure 1D, except that nuclear fragmentations are highlighted here. (I) Nuclear fragmentation in cells expressing Nup49-mCherry and Fob1-GFP (A34453). The bright shading in the green channel is caused by autofluorescence of the medium. The arrowhead highlights a nuclear flare. (J) Nuclear fragmentation in a cell expressing Ndc80-GFP and Whi5-tdTomato (A40283). (K) Nuclear fragmentation in a cell expressing Ndc80-GFP and Cfi1-tdTomato (A40284).