Figure 4. Locally activated H2B-miniSOG can induce cellular senescence.

(A-B) HeLa cells expressing H2B-miniSOG were synchronized in S phase, illuminated with blue (465-495 nm, 65 mW/cm², 5 min) light, allowed to recover for 24 hr, and stained for γH2AX (A) or SA-β-gal (B). Only part of each specimen was illuminated. Dashed line shows the boundary between illuminated and non-illuminated parts of the specimens. Scale bars: 100 μm (A) and 80 μm (B).