Figure 4.

Set8 but not H4^K20 mutant cells fail to proliferate. (A,B) Diagram of w⁺/w⁻ mosaic eye generation using FLP-FRT-mediated mitotic recombination. (A) The Set8 wild-type (white box) control experiment results in an adult eye with an equal mixture of red and white tissue. (B) The Set8^null (open white box) experiment results in only red tissue because homozygous Set8^null cells fail to proliferate. (C) Single optical sections of genetically mosaic eyes composed of clonal populations of cells that are homozygous for Act5C-GFP and HisC⁺ (green) or homozygous for ΔHisC^cadillac and lacking Act5C-GFP (magenta) rescued by the indicated control or H4K20 mutant transgenes. (D) Same as C except in a His4r^null mutant background. The right column shows merged images of the pseudocolored histone mutant clones (magenta) and sister histone wild-type clones (green). (E) Quantification of mosaic eye clones in C and D. Box plot showing the fraction of mutant tissue (magenta) for 19–20 eyes of each genotype (10 males and nine to 10 females each). Black dots indicate measurements from individual eyes. Significance was determined by Student's t-test. (****) P < 0.0001, (*) P < 0.05.