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. 2002 Nov;4(6):531–538. doi: 10.1038/sj.neo.7900267

Figure 1.

Figure 1

Structure of the integrated plasmid sequences and length of seeded telomeres in EJ-30 clones A3 and B3. (A) Clones A3 and B3 contain a single copy of the pNCT-tel plasmid integrated on the end of a chromosome. The locations of the cellular DNA, plasmid vector (amp/ori), neo gene, HSV-tk gene, and telomeric repeat sequences are shown. The location of BamHI restriction sites (Bm) used for Southern blot analysis and the size of the BamHI restriction fragments are shown. (B) Southern blot analysis of BamHI-digested genomic DNA from clones A3 and B3, and subclones 1 through 5 selected at random from each clone. Hybridization was performed with the pNCT-Δ probe, which is identical to pNCT-tel except that it does not contain telomeric repeat sequences. (C) Southern blot analysis of BamHI-digested genomic DNA from clone B3 and its subclones B3-1 and B3-2 after different numbers of cell doublings using the pNCT-Δ plasmid as a probe. The internal BamHI fragments in clones A3 and B3 are both approximately 4.5 kb in length. The terminal fragments containing 4.4 kb of plasmid sequences are heterogeneous in length due to variability in the length of the telomeres in different cells in the population. Molecular size markers consisting of Lambda bacteriophage HindIII restriction fragments are shown.