Figure 6. Dependence of loss of Bu-1a expression and histone marks around the TSS on the distance between the +3.5 G4 motif and the TSS.

Bu-1a loss is reduced as the G4 motif is moved further from the TSS. The cartoons show the position of the +3.5 G4 motif following manipulation of the BU-1A locus in which the natural +3.5 G4 motif has already been deleted from both the BU1A and BU1B allele (i). Only the first three exons are shown. (ii) The +3.5 G4 motif reintroduced into its native position. (iii–v) The +3.5 G4 DNA reintroduced with additional spacers placing it 4 kb, 4.5 kb and 6 kb from the TSS. To the right of the cartoons are the corresponding fluctuation analyses for Bu-1a loss. Each point represents the percentage of Bu-1a^low variants from single Bu-1a^high cells expanded for 20 generations. Red bar = median loss; whiskers = interquartile range; P-values that each distribution is different from control (i) calculated with Fisher's exact test with a bin size of 20%. NS = not significant (P < 0.001).