Figure 5

Insertion prediction for transposon vectors surrounding the c-myc locus on mouse chromosome 15. A 3 kilobase sequence from the mouse c-myc locus (from 61,813,400 to 61,816,400 base pairs) harboring 37 retroviral insertions submitted to the Mouse Retrovirus Tagged Cancer Gene Database [155] is shown. The first exon and intron of c-myc are shown in orange; the upstream promoter sequence is shaded in yellow. (a) Retrovirus insertion frequency per 50 base pair (bp) segment. Panels (b) to (g) show DNA structural characteristics at 50 bp resolution. (b) Total V _step for each bin across the region. (c) Total V _step jaggedness. (d) Total A-philicity values. (e) Total trinucleotide bendability. (f) Number of TTAA sequences per 50 bp bin, representing the total number of possible piggyBac insertion sites. Notably, many regions harboring oncogene-selected retroviral insertions have few or no TTAA sequences, suggesting that the likelihood of a piggyBac insertion causing an oncogenic event may be lower than that for retroviruses. Arrow represents a potential 'hotspot' for integration, over 1 kilobase upstream of exon 1. (g) ProTIS prediction shows a similar, low incidence of preferred SB integration sites. Arrow indicates predicted hotspot for integration over 1 kilobase upstream of exon 1, and slightly upstream of the TTAA hotspot. SB, Sleeping Beauty.