Detection of the amplified plasmid sequence by FISH.

<p>Representative images obtained in this study are shown. Plasmid pTV-Rep-P bearing full-length Rep-P sequence was transfected to COLO 320DM cells (A to C) or CHO-DG44 cells (D). Metaphase chromosome spreads were prepared from the stable transfectants, and the plasmid sequence was detected by FISH. Long HSR appeared in the metaphase cells (A and B) or a interphase cell (A). The DMs with plasmid sequence appear in the metaphase cells in panel B and C as well as an interphase cell in panel C. In CHO-DG44 cells, the same plasmid did not generate long HSR, instead it remained as the short HSRs that were arrowed (D), as explained in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0077350#pone-0077350-g001" target="_blank">Figure 1</a>.