Figure 6. Polo and BubR1 Are Also Present in Ald-Containing Filaments.

(A) Polo-GFP/Ald colocalization A fixed oocyte from a polo-GFP homozygous female, showing that only Polo localizes along the meiotic tubulin spindle, while both Ald and Polo colocalize to kinetochores and along the cytoplasmic filaments. The chiasmate chromosomes appear slightly abnormal, possibly due to overexpression of Polo, but achiasmate X NDJ was no more than 1%–3% (our unpublished observations).

(B) Polo-GFP still highlights filaments in ald mutant oocytes. A fixed oocyte from a polo-GFP/+; ald^Exc23 female. This ald allele greatly reduces, but does not eliminate, the dosage of wild-type Ald present (see Figure 5B). Ald staining is mostly in discrete foci, some of which are close enough together to be interpreted as filaments (arrows). However these filaments still contain Polo-GFP fluorescence, which appears undisturbed by the reduction in Ald dosage.

(C) Unfixed Polo-GFP also highlights filaments GFP fluorescence from an unfixed polo-GFP oocyte, with filaments qualitatively similar to those seen in fixed images. Due to the lack of a DNA marker, the location of these filaments relative to the oocyte nucleus could not be determined, but based on Polo-GFP localization to the spindle (see Figure 6A), the oocyte nucleus does not appear to be in the imaged region.

(D) BubR1 can also highlight filaments. In ten out of 33 FM7/X oocytes, BubR1 was found to weakly highlight some filaments visualized by Ald antibody. This figure represents the best staining observed; in most oocytes the staining was weaker (but still detectable) and only present in a subset of filaments.