HOMOLOGOUS ASSOCIATION OF CHROMOSOMAL DNA DURING YEAST MEIOSIS
HOMOLOGOUS ASSOCIATION OF CHROMOSOMAL DNA DURING YEAST MEIOSIS
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DOI：
10.1101/sqb.1983.047.01.095
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发表时间：
1982-01-01
期刊：
影响因子：
--
通讯作者：
BYERS, B
中科院分区：
文献类型：
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作者：
BELL, LR;BYERS, B
减数分裂前期值得注意的事件是同源染色体之间发生的相互作用。电子显微镜研究揭示了染色体行为的结构框架（Moses 1968），并提供了以下事件概述。在配对变得明显之前，每条染色体都获得了一个致密的轴向核心。在偶线期，同源染色体的轴向核心逐渐变得彼此相邻排列，最终导致在粗线期形成完整的联会复合体。各种遗传学观察表明，交换主要是一个粗线期事件，虽然某些必要的条件可能在早期阶段建立（亨德森1970）。交换的位点似乎在粗线期被“重组结节”标记，重组结节是位于联会复合体的一个边缘的小的、染色密集的小体。野生型和减数分裂缺陷株中结节的空间分布强烈表明它们占据了重组位点（Carpenter 1979 a，B）。这些细胞学观察的分辨率不足以揭示同源染色体DNA分子之间的任何相互作用。配对和重组的机制必须从生物化学和遗传数据中推断出来。Stern和Hotta（1977）关于百合减数分裂DNA代谢的关键性工作表明，偶线期配对伴随着某些独特DNA序列的保守性复制的延迟完成，这种合成对于正确的染色体联会是必不可少的。在粗线期，重复的DNA序列的再合成是有限的，大概是在这个阶段产生的核酸内切酶活性导致DNA切口的位点。配对是这种修复合成的必要前提。
The notable events of meiotic prophase are the interactions that take place between homologous chromosomes. The structural framework underlying chromosome behavior has been revealed by electron microscopy studies (Moses 1968), which have provided the following outline of events. Before pairing becomes evident, each chromosome gains a dense axial core. During zygotene, the axial cores of homologous chromosomes gradually become aligned adjacent to one another, finally leading to formation of the complete synaptonemal complex at pachytene. A variety of genetic observations suggest that crossing-over is largely a pachytene event, although certain essential conditions may be established at earlier stages (Henderson 1970). Sites of crossing-over appear to be marked at pachytene by" recombination nodules," small, densely staining bodies situated at one edge of the synaptonemal complex. The spatial distribution of the nodules in both wild-type and meiotically defective strains strongly indicates that they occupy sites of recombination (Carpenter 1979a, b).The resolution of these cytological observations is not sufficient to reveal anything of the interactions between DNA molecules of the homologous chromosomes. The mechanisms of pairing and recombination must be inferred from biochemical and genetic data. The pivotal work by Stern and Hotta (1977) on meiotic DNA metabolism in Lilium indicates that zygotene pairing is accompanied by the delayed completion of semiconservative replication of certain unique DNA sequences and that this synthesis is essential to proper chromosome synapsis. At pachytene there is limited resynthesis of repeated DNA sequences, presumably at sites where an endonuclease activity arising at this stage has caused nicks in the DNA. Pairing is a necessary precondition for this repair synthesis.