FIG. 10.

Restriction enzyme accessibility assay in lymphosarcoma cells after treatment with 5-AzaC and TSA. Nuclei isolated from identical numbers of cells (4 × 10⁶) from each group were incubated with 50 U of AluI at 37°C for 10 min (lanes 4, 6, 8, and 10). Nuclei incubated in the same buffer without restriction enzyme were used as controls (lanes 3, 5, 7, and 9). DNA was purified from the nuclei, and 1 μg was digested in vitro with a second enzyme, e.g., MspI in panel A or TaqI in panel B. Identical amounts (250 ng) of DNA from each group and naked DNA digested with respective restriction enzymes were subjected to LM-PCR with strand-specific primers as described in Materials and Methods (the third primer is labeled with ³²P). Lanes 1 and 2 contain naked DNA digested with MspI and AluI (A) and TaqI and AluI (B). The reaction product was separated on a sequencing gel and subjected to autoradiography and PhosphorImager analysis. Lanes M contain the 20-bp ladder.