Figure 4

Analysis of chromatin organization in sodium butyrate induced senescent NH3T3 cells. (A-D) NIH3T3 cells were treated with sodium butyrate for 2 or 4 days and then stained with Hoechst 33258 for visualizing chromatin. (E-H) is a magnified view of the field in boxes in A-D respectively. (I) Quantitative analysis of the nucleoli in sodium butyrate treated cells with chromatin re-organized from outside to inside the nucleolus. About 200 nucleoli were counted in the treated and control cells and the number expressed as a percentage of the nucleoli in which chromatin was found to be inside the nucleoli. (J-Q) Assessment of in situ rRNA transcriptional sites in the 4 day sodium butyrate treated senescent NIH3T3 cells by 5-fluorouridine labeling followed by staining with BrdU antibody (Red). (J-M) depicts control cells while (N-Q) depicts sodium butyrate treated cells. The detailed magnified view of the areas in broken boxes is shown in M and Q.