Chacón Mariola R, Delivani Petrina, Tolić Iva M
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia.
Cell Rep. 2016 Nov 1;17(6):1632-1645. doi: 10.1016/j.celrep.2016.10.014.
Pairing of homologous chromosomes is a crucial step in meiosis, which in fission yeast depends on nuclear oscillations. However, how nuclear oscillations help pairing is unknown. Here, we show that homologous loci typically pair when the spindle pole body is at the cell pole and the nucleus is elongated, whereas they unpair when the spindle pole body is in the cell center and the nucleus is round. Inhibition of oscillations demonstrated that movement is required for initial pairing and that prolonged association of loci leads to mis-segregation. The double-strand break marker Rec25 accumulates in elongated nuclei, indicating that prolonged chromosome stretching triggers recombinatory pathways leading to mis-segregation. Mis-segregation is rescued by overexpression of the Holliday junction resolvase Mus81, suggesting that prolonged pairing results in irresolvable recombination intermediates. We conclude that nuclear oscillations exhibit a dual role, promoting initial pairing and restricting the time of chromosome associations to ensure proper segregation.
同源染色体配对是减数分裂中的关键步骤，在裂殖酵母中，这一过程依赖于细胞核振荡。然而，细胞核振荡如何促进配对尚不清楚。在此，我们表明，当纺锤极体位于细胞极且细胞核拉长时，同源位点通常会配对，而当纺锤极体位于细胞中心且细胞核呈圆形时，它们会解聚。对振荡的抑制表明，运动是初始配对所必需的，并且位点的长时间关联会导致错误分离。双链断裂标记物Rec25在拉长的细胞核中积累，表明染色体的长时间拉伸会触发导致错误分离的重组途径。通过过表达霍利迪连接解离酶Mus81可挽救错误分离，这表明长时间配对会导致无法解决的重组中间体。我们得出结论，细胞核振荡具有双重作用，促进初始配对并限制染色体关联的时间，以确保正确分离。
