Research Paper Volume 4, Issue 6 pp 431—435
Replicatively senescent cells are arrested in G1 and G2 phases
Figure 1. Senescent human fibroblast cultures contain a large fraction of putative G2-arrested cells with 4N DNA content. (A) Propidium iodide (PI) staining and flow cyctometric analysis of HCA2 normal human foreskin fibroblasts. Cells entered senescence at PD73. (B) PI staining of replicatively senescent human lung fibroblasts WI-38, and IMR-90 at PDs 73 and 68 respectively. (C) The fraction of 4N cells in senescent cell population does not diminish with time. Replicatively senescent HCA2 cells were analyzed by PI staining at weekly intervals for 10 weeks stating from the onset of senescence.