Fig. 6. Organisation of the polar body in wild-type and bubR1^Rev1 embryos. (A-C) In merged images, BubR1 is in red, DNA in blue and CID in green. (A-A''') BubR1 localises at kinetochores of polar body chromosomes in wild-type embryos. (B,B''') In unfertilised bubR1^Rev1 embryos, polar body chromosomes fail to maintain a prometaphase arrest and appear decondensed. (C,C''') In fertilised bubR1^Rev1 embryos, polar body chromosomes are mostly decondensed and show an increased number of CID-positive signals. (D-G) DNA is in blue and Phospho-Histone H3 in red in merged images. (D,D'') In wild-type embryos, polar bodies have condensed Phospho-Histone H3 positive chromosomes. (E,E'') In unfertilised bubR1^Rev1 embryos, polar bodies show DNA condensation with a low Phospho-Histone H3 signal and alteration of chromosome configuration. (F,F'',G,G'') In fertilised bubR1^Rev1 embryos, the polar bodies follow cycles of condensation-decondensation. (F') The polar body is Phospho-Histone H3 negative and shows a decondensed interphase-like state or (G-G'') shows a low Phospho-Histone H3 positive labelling and partial DNA condensation. (H) Quantification of Phospho-Histone H3-positive polar bodies in wild-type and bubR1^Rev1 embryos: fertilised wild-type embryos (Ft Wt, n=30), unfertilised bubR1^Rev1 embryos (Unf bubR1^Rev1, n=30), fertilised bubR1^Rev1 embryos with syncytial nuclei in interphase (Int bubR1^Rev1, n=11) and fertilised bubR1^Rev1 embryos with syncytial nuclei in mitosis (Mit bubR1^Rev1, n=30). Scale bar: 10 µm.