Fig. 2. (A) Representative centromere (green) and (B) XY' telomere FISH signal patterns (red) in mildly spread nuclei (DAPI, blue) obtained from synchronized meiotic cultures of meiosis-proficient haploid sir3 spo13 control strain (haploid), a corresponding haploid kar3 sir3 spo13 strain (haploid kar3), a diploid sir3 strain (diploid sir3) and a tetraploid strain (tetraploid). All strains were of identical SK1 background. The FISH patterns observed are ordered according to their deduced sequential occurrence and match those observed in diploid wild-type SK1 meiosis (Trelles-Sticken et al., 2000). (A, left) Premeiotic nuclei (0 minutes, fixed at transfer to SPM) with a single centromere signal cluster (green). (A, right) Meiocyte nuclei (taken at 300 minutes) exhibit dispersed centromere signals. Notice the increase in cen-cluster size from haploid to tetraploid. (Bi) Premeiotic nuclei (0 minutes) of all strains display a few telomere FISH signal clusters (red). (Bii) Early meiocytes exhibiting a meiosis-specific rim-like telomere distribution (Hayashi et al., 1999; Trelles-Sticken et al., 2000). (Biii) Bouquet nuclei of all strains, which exhibit telomere FISH signals clustered at a limited region of the nuclear periphery. (Biv) Meiocyte nuclei showing dispersed telomere FISH signals, which is typical for pachytene (Trelles-Sticken et al., 1999). (C) Colocalization of clustered telomeres (red) and the SPB (green). In the diploid sir3 and tetraploid SK1 strain, telomeres and SPB were visualized by XY' telomere FISH in combination with Tub4 IF, whereas telomeres in the haploid control and haploid kar3 strain were stained by Ndj1-HA IF. Notice the rise in nuclear diameter and signal numbers with increase in ploidy. Bar, 5 µm.

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