Figure 3.

Fragile region topography near cancer cell breakpoints. Depiction of 10 deletion endpoints relative to L1 elements (L1 sequences of >1 kb, bold arrows; L1 sequences of <1 kb, small arrowheads) and LTR/retroviral elements. The four squares enclosing L1 elements emphasize that the TE8 breakpoints, the telomeric Siha breakpoint, the translocation point, and the telomeric breakpoint of H1573 are located within or near L1 elements. The two circles enclosing LTR arrowheads stress that the H460/H211 breakpoints and the centromeric breakpoint of Siha allele a are near LTR/retroviral elements. The dashed vertical lines represent the flexibility spikes A–G (shown in Fig. 2) and show the position of flexibility/fragility spikes relative to cancer cell deletions. For the HeLa and TE8 cell lines, the exact structure of the b alleles in this region is not yet known.