Fig. 4.
Female chZ shifts toward the nuclear center and undergoes changes in shape in late embryos. (A) Quantification of CT position. Nuclei are divided into nine shells of equal volume, with shell 1 being most peripheral and shell 9 being most central. The 3D volume of each chromosome paint in each nuclear shell is quantified. Shown are averages and SE across at least three biological replicates (embryos or larvae), where at least 100 cells were measured per replicate. Statistics: χ2 test. *P = 0.03. (B) Three-dimensional rendering of female (Left) or male (Right) nuclei showing ch23 (blue) or chZ (pink) in late embryos. (C) Bar graph showing chZF volume as a fraction of nuclear volume in mid embryos (Left), late embryos (Center), and larval heads (Right). Each dot represents the average of a biological replicate. (D) Tukey box-and-whisker plot showing quantification of chromosome shape (compacity; y axis) for individual chromosomes at the indicated time points. Midline: median. Statistics: Welch’s t tests. *P < 0.05. Blue dashed lines indicate the shape range of ch23. (E, Left) Schematic of stripe Oligopaints for female chZ. (Right) Three-dimensional rendering of stripe paints in female late embryos or larvae. (F) Quantification of fraction of chZF in unfolded (Left) or folded (Right) configuration in late embryos (lavender) and larvae (purple). Statistics: Fisher’s exact test comparing unfolded versus folded chromosomes in embryos and larvae. **P < 0.01.