Chromosomes Rein Back the Spindle Pole Body during Horsetail Movement in Fission Yeast Meiosis

Abstract

ABSTRACT. In meiosis, pairing and recombination of homologous chromosomes are crucial for the correct segregation of chromosomes, and substantial movements of chromosomes are required to achieve homolog pairing. During this process, it is known that telomeres cluster to form a bouquet arrangement of chromosomes. The fission yeast Schizosaccharomyces pombe provides a striking example of bouquet formation, after which the entire nucleus oscillates between the cell poles (these oscillations are generally called horsetail nuclear movements) while the telomeres remain clustered to the spindle pole body (SPB; a centrosome-equivalent structure in fungi) at the leading edge of the moving nucleus. S. pombe mutants defective in telomere clustering frequently form aberrant spindles, such as monopolar or nonpolar spindles, leading to missegregation of the chromosomes at the subsequent meiotic divisions. Here we demonstrate that such defects in meiotic spindle formation caused by loss of meiotic telomere clustering are rescued when nuclear movement is prevented. On the other hand, stopping nuclear movement does not rescue defects in telomere clustering, nor chromosome missgregation even in cells that have formed a bipolar spindle. These results suggest that movement of the SPB without attachment of telomeres leads to the formation of aberrant spindles, but that recovering bipolar spindles is not sufficient for rescue of chromosome missegregation in mutants lacking telomere clustering.

Lem2 is retained at the nuclear envelope through its interaction with Bqt4 in fission yeast

“…All insertions were confirmed by sequencing. The plasmids used for the expression of GFP‐Bqt4 (pCSS80), Sid4‐mRFP and GFP‐Man1 have been previously reported (Chikashige et al., , ; Tange et al., ).…”

Control of Meiotic Crossovers: From Double-Strand Break Formation to Designation

“…In addition, the telomeres of many species appear to cluster within a limited domain of the nuclear envelope, resulting in a chromosome configuration known as the telomere bouquet (241). The classic example of chromosome movements and telomere clustering is provided by Schizosaccharomyces pombe , in which the telomeres cluster at the spindle pole body and the entire nucleus oscillates between the cell poles, a movement often described as the horsetail (46, 114). Centromere association appears to be important also, at least in certain species, including S. cerevisiae , S. pombe , A. thaliana , and D. melanogaster (reviewed by 58).…”

Fission Yeast Scp3 Potentially Maintains Microtubule Orientation through Bundling

“…The flow pressure was 1 psi. Fluorescence microscope images were obtained by the DeltaVision microscope system (Applied Precision, Inc.) set up in a temperature-controlled room as previously described [41,42]. This microscope system is based on an inverted fluorescence microscope (IX71; Olympus) equipped with a charge-coupled device (CoolSNAP HQ2; Photometrics).…”

“…The objective lens used was an oil immersion Plan-Apo 60 × NA = 1.4 lens (Olympus). A stack of nine slices (0.3 μm distance between planes) was projected with softWoRx software (Applied Precision, Inc.) using a maximum intensity method [41,42]. …”