Figure 5.—

scs′ does not function as an insulator in BEAF^AB-KO flies, but the scs and gypsy insulators are still functional. (A) The M2 insulator, an scs′ derivative, does not protect against chromosomal position effects in the absence of BEAF protein. Eyes of 3- to 4-day-old females heterozygous for different M2 transposons and homozygous for BEAF or BEAF^AB-KO (KO) are shown. See text for details. (B) A dimer of the scs′ insulator does not block communication between the y wing and body enhancers and the y promoter in the absence of BEAF protein. Lack of BEAF protein does not affect the ability of the scs and gypsy insulators to block this enhancer–promoter communication. Shown are abdomens of 3- to 4-day-old females homozygous for BEAF or BEAF^AB-KO (KO) and heterozygous for the indicated transposons, with (Ins) or without [del(Ins)] the indicated insulator between the enhancer and promoter. See text for details.