Kinetic analysis of synaptonemal complex dynamics during meiosis of yeast Saccharomyces cerevisiae reveals biphasic growth and abortive disassembly.
Kinetic analysis of synaptonemal complex dynamics during meiosis of yeast Saccharomyces cerevisiae reveals biphasic growth and abortive disassembly.
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DOI：
10.3389/fcell.2023.1098468
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发表时间：
2023
影响因子：
5.5
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中科院分区：
文献类型：
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突触复合体（synaptonemal complex， SC）是染色体在减数分裂过程中形成的一种动态结构，它稳定并支持许多重要的减数分裂过程，如配对和重组。在出芽酵母中，Zip1是SC的一个功能保守元件，对突触很重要。在此，我们直接测量了Zip1-GFP在酿酒酵母活细胞中的组装和拆卸动力学。酵母中SC组装的成像是具有挑战性的，因为大量的染色体被包装成一个小的细胞核。我们采用zip3Δ突变体，其中在任何给定时间只有少数染色体进行突触，从每条染色体上的单个位点开始，从而允许在活细胞中精确监测单个SCs的组装和拆卸动力学。与秀丽隐杆线虫中所见的严格的单相组装相反，SC组装发生在单相和双相动力学中。在野生型细胞中，一旦达到最大突触，随着Zip1蛋白的活性降解，程序化的最终解体迅速随之而来。在zip3Δ中，这段时间被延长，最终的拆卸被延长。除了最终拆卸外，我们还发现了新的拆卸事件，这些事件主要涉及在程序最终拆卸之前消失的短SCs，我们将其称为“流产拆卸”。流产性拆卸与最终拆卸的不同之处在于，流产性拆卸发生在Zip1蛋白水平仍然很高的时候，并且其拆卸速度要慢得多，这表明两种拆卸类型的去除机制不同。我们推测，失败的拆卸事件代表有缺陷或停滞的SC，可能代表非同源物之间的SC形成，然后靶向溶解。这些结果揭示了SC组装和拆卸的新方面，潜在地提供了额外的调节途径的证据，不仅控制组装，而且还控制拆卸，这种复杂的细胞结构。
The synaptonemal complex (SC) is a dynamic structure formed between chromosomes during meiosis which stabilizes and supports many essential meiotic processes such as pairing and recombination. In budding yeast, Zip1 is a functionally conserved element of the SC that is important for synapsis. Here, we directly measure the kinetics of Zip1-GFP assembly and disassembly in live cells of the yeast S. cerevisiae. The imaging of SC assembly in yeast is challenging due to the large number of chromosomes packed into a small nucleus. We employ a zip3Δ mutant in which only a few chromosomes undergo synapsis at any given time, initiating from a single site on each chromosome, thus allowing the assembly and disassembly kinetics of single SCs to be accurately monitored in living cells. SC assembly occurs with both monophasic and biphasic kinetics, in contrast to the strictly monophasic assembly seen in C. elegans. In wild-type cells, once maximal synapsis is achieved, programmed final disassembly rapidly follows, as Zip1 protein is actively degraded. In zip3Δ, this period is extended and final disassembly is prolonged. Besides final disassembly, we found novel disassembly events involving mostly short SCs that disappeared in advance of programmed final disassembly, which we termed “abortive disassembly.” Abortive disassembly is distinct from final disassembly in that it occurs when Zip1 protein levels are still high, and exhibits a much slower rate of disassembly, suggesting a different mechanism for removal in the two types of disassembly. We speculate that abortive disassembly events represent defective or stalled SCs, possibly representing SC formation between non-homologs, that is then targeted for dissolution. These results reveal novel aspects of SC assembly and disassembly, potentially providing evidence of additional regulatory pathways controlling not just the assembly, but also the disassembly, of this complex cellular structure.
影响因子：
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作者：
Dobbie IM;King E;Parton RM;Carlton PM;Sedat JW;Swedlow JR;Davis I
通讯作者：
Davis I