Fig. 5. Presence of Z4 in chromosomes of Z4 hypomorphic mutants. (A) Chromosomes were squashed from 3rd instar larvae homozygous mutant for Z4-7.1. The DNA of the squashed chromosomes was stained with Sytox Green (green) and with the Z4 antibody (red). The composite image shows the localization of Z4 to some telomeres in addition to a few internal chromosomal sites, which are still complementary to the DNA staining. (B,C) Chromosomes from homozygous mutant larvae of the line Z4-1.3 that were rescued by the expression of the Z4 cDNA were squashed and stained with DAPI (blue) and the Z4 antibody (red). Compared with its staining of the interbands, Z4 is concentrated on the telomere of the X chromosome (B) and on the telomere of the left arm of chromosome 2 (C).