Fig. 2

Chromosomal abnormalities. Metaphase chromosomal spreads were prepared from MSCs with the following genotypes a pure wild-type C57/Bl6 (C57 WT) cells; c EWS-FLI1 p53−/− cells expressing random control shRNA (Ctrl shRNA cells); and e EWS-FLI1 p53−/− cells expressing Stag2 shRNA (Stag2 shRNA cells). Examination of 125 metaphase spreads showed more abnormal metaphases for Ctrl shRNA and Stag2 shRNA cells compared to C57 WT cells. Ctrl shRNA and Stag2 shRNA cells exhibited frequent non-reciprocal translocations (red arrows), chromosomal fragments (blue arrows) and chromosomal breaks (green arrows). However, there was no significant difference between Ctrl shRNA and Stag2 shRNA cells in terms of percentage of aberrant metaphases (34% vs. 34%, respectively), chromosomal breaks (18% vs. 16%, respectively), and chromosomal fusions/translocations (24% vs. 24%). b The cell cycle distribution of C57/Bl6 WT cells stained with propidium iodide (PI) showed 89.1% of cells in G0-G1, 2.1% in S, and 7.6% in G2-M phases. Cell cycle distribution of Ctrl shRNA cells d and Stag2 shRNA cells f showed a higher fraction of non-G0-G1 cells compared to the control C57 WT cells. The cell cycle distribution of Ctrl shRNA cells was not statistically different compared to Stag2 shRNA cells