Fig. 6. DNA content of E2f2 mutant follicle cells determined by FACS analysis. (A) Nuclei preparations from yw⁶⁷ wild-type ovaries were stained with propidium iodide and subjected to FACS analysis. Nuclei with 2C DNA content are from mitotically active follicle cells, and the three follicle cell endocycles give rise to the 4C, 8C and 16C nuclei. A small 32C peak is always observed in wild type, probably from other less abundant cell types in the ovary (e.g. nurse cells). (B) FACS profile of nuclei prepared from Df(2L)E2f2³²⁹/Df(2L)DS8, P[E2f2^1-188; Mpp6⁺] ovaries. The size of the 32C peak varies between preparations, with this particular profile containing the largest peak obtained. (C) Intact follicle cells were prepared from c323:GAL4/+; Df(2L)E2f2³²⁹/+; UAS-GFP/+ ovaries and subjected to FACS analysis. The open profile represents signal from the DNA-binding dye Hoechst 33342, and the shaded profile represents GFP-positive cells. The GAL4 driver begins expression during stage 9 and continues until the end of oogenesis. By stage 9, all follicle cells have completed the first endocycle S phase, and therefore GFP-positive cells are only found in the 8C and 16C populations. (D) FACS profile of follicle cell preparations from c323:GAL4/+; Df(2L)E2f2³²⁹/Df(2L)DS8, P[E2f2^1-188; Mpp6⁺]; UAS-GFP/+ ovaries. Note that the profile is similar to wild type, indicating that E2f2 mutant follicle cells do not achieve a 32C ploidy value. (E) FACS profile of follicle cell preparations from Rbf¹²⁰/Rbf¹⁴ ovaries. Note the population of cells at 32C. (F) Equal amounts of follicle cells prepared from yw⁶⁷ and Rbf¹²⁰/Rbf¹⁴ ovaries were mixed prior to FACS analysis, because the 16C peak was reproducibly small in the Rbf mutant preparations. Note that five peaks are clearly visible when compared with wild type (C).