Figure 7. Impaired nuclear barrier strength correlates with an increased lifespan.

(A) Detection of DNA circles by Southern blotting in young and aged cells grown at 30°C and 37°C (2% glucose). Young cells were 0–1 generation and aged cells were 16 generations old. The quantification of the relative band intensity is based on four bands of concatenated DNA circles. Band sizes of a DNA marker are indicated. (B–C) Lifespan analysis. Median lifespan (in brackets) of 40 ≤ n ≤ 79 cells per condition. two independent pooled experiments per condition. For comparison purposes: the lifespan curves of wild type cells (2% and 0.1% glucose, 30°C) in Figure 7A and Figure 7B are the same. Log Rank (Mantel-Cox) test, **p<0.01. (D) Simplified: heat stress specifically weakens the nuclear diffusion barrier, thus fostering a more symmetric segregation of DNA circles to the daughter and accordingly promoting longevity.