Figure 4.
acf1 contributes to Polycomb silencing and pericentric position-effect variegation (PEV). (A) Eye phenotypes of flies with In(1)wm4h in homozygous wild type control (acf13) genetic background. (B) Eye phenotypes of flies with In(1)wm4h in homozygous acf1 null (acf11) genetic backgrounds. Homozygous acf1 null flies exhibit strong suppression of PEV. (C,D) Eye phenotypes of flies with pericentric (C3) white transgene KV123 in heterozygous wild-type control (acf13) and acf1 null (acf11) genetic backgrounds. In E to H, flies were produced in a cross between y; KV123/KV123 males and yw/yw; acf1/acf1 females. The offspring of homozygous acf1 null mothers exhibit strong suppression of PEV. (E,F) Abdomen pigmentation phenotypes of flies with pericentric (C3) yellow transgene KV123 in heterozygous wild-type control (acf13) and acf1 null (acf11) genetic backgrounds. (G,H) Eye phenotypes of flies with a telomeric (T2L) hsp70-white transgene (39C-5) insertion (Cryderman et al. 1999a) in wild-type control (acf13) and acf1 null (acf11) genetic backgrounds. Telomeric PEV is not affected by loss of acf1. Similar results were obtained for insertions 39C-27 in T2R and 39C-72 in T4 (data not shown). (I,J) Eye phenotype of flies with homozygous insertion of 2212H6.5+PBX (PRE-white) transposon on the second chromosome (Chan et al. 1994) in homozygous wild-type control (acf13) and homozygous acf1 null (acf11) genetic backgrounds, respectively. Weak variegated expression of the white transgene is indicated by arrows. The PRE-white transgene is derepressed in acf1 null flies. In A, B, and G–J, representative phenotypes of 6- to 7-day-old females are shown. In C–F, representative phenotypes of 6- to 7-day-old males are shown. (Left column) Genetic backgrounds of the flies. (Bottom line) Names of stocks and location of aberrations/transposon inserts. (2L) Left arm of the second chromosome; (C1) centromere of the X chromosome; (C3) centromere of the third chromosome; (T2L) telomere of the left arm of the second chromosome; (T2R) telomere of the right arm of the second chromosome; (T4) telomere of the fourth chromosome; (PRE) Polycomb response element.