Unusual nuclear structures in meiotic prophase of fission yeast: a cytological analysis.
Unusual nuclear structures in meiotic prophase of fission yeast: a cytological analysis.
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DOI：
10.1083/jcb.121.2.241
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发表时间：
1993-04
影响因子：
7.8
通讯作者：
Kohli, J
中科院分区：
文献类型：
--
作者：
Bahler, J;Wyler, T;Loidl, J;Kohli, J
早期细胞核切片的结果表明粟酒裂殖酵母在减数分裂前期不会发育出典型的三重联会复合体（SC），这一结果通过整个细胞核的伸展得到了证实。在前期I出现的线性元件类似于其他生物体的轴向核心（SC前体）。在单倍体、二倍体和四倍体品系中线性元件的数目总是高于染色体数目，这意味着它们不是沿着染色体连续形成的。时程实验表明，这些元件在DNA复制后出现，并形成网络和束。随后它们分离，在降解和减数分裂之前观察到大约24个总长度为34微米的单个元件。DNA的平行染色揭示了减数分裂前期核形状的变化。具有mei4突变的菌株在后期前期阶段被阻断。在连续切片中，我们还观察到一个恒定的安排纺锤体极体，核仁，和假定的着丝粒簇。因此，S。粟酒裂殖酵母在没有SC的情况下能够重组和分离染色体，这可能与没有交叉干扰有关。我们提出了一种机制，染色体配对与初始识别的同源物在着丝粒和建议功能的线性元件在准备染色体减数分裂I分离。随着遗传学、分子生物学和细胞学技术的发展，在S.粟酒这提供了一个机会，研究必要的减数分裂功能的情况下，SC，这可能有助于澄清的意义SC及其组件的减数分裂染色体的结构和功能。
Earlier results from sectioned nuclei indicating that Schizosaccharomyces pombe does not develop a classical tripartite synaptonemal complex (SC) during meiotic prophase are confirmed by spreading of whole nuclei. The linear elements appearing during prophase I resemble the axial cores (SC precursors) of other organisms. The number of linear elements in haploid, diploid, and tetraploid strains is always higher than the chromosome number, implying that they are not formed continuously along the chromosomes. Time course experiments reveal that the elements appear after DNA replication and form networks and bundles. Later they separate and approximately 24 individual elements with a total length of 34 microns are observed before degradation and meiotic divisions. Parallel staining of DNA reveals changes in nuclear shape during meiotic prophase. Strains with a mei4 mutation are blocked at a late prophase stage. In serial sections we additionally observed a constant arrangement of the spindle pole body, the nucleolus, and the presumptive centromere cluster. Thus, S. pombe manages to recombine and segregate its chromosomes without SC. This might correlate with the absence of crossover interference. We propose a mechanism for chromosome pairing with initial recognition of the homologs at the centromeres and suggest functions of the linear elements in preparation of the chromosomes for meiosis I disjunction. With the spreading technique combined genetic, molecular, and cytological approaches become feasible in S. pombe. This provides an opportunity to study essential meiotic functions in the absence of SCs which may help to clarify the significance of the SC and its components for meiotic chromosome structure and function.