Protect chromosomes from end-to-end fusion during meiotic bouquet
Protect chromosomes from end-to-end fusion during meiotic bouquet
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DOI：
10.1007/s11427-018-9299-9
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发表时间：
2018-05
期刊：
影响因子：
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通讯作者：
Shunxin Wang;B. Zhai;X. Yang;Liangran Zhang
中科院分区：
文献类型：
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作者：
Shunxin Wang;B. Zhai;X. Yang;Liangran Zhang
减数分裂产生的配子有一半的父母染色体互补，因此是成功的有性生殖的关键。在减数分裂前期I期间，发生一系列特化事件以确保在后期I期间正确的父本和母本同源染色体（同源物）分离。它们包括同源物的识别、比对、配对和突触以及提供同源物之间联系的减数分裂重组。在细线期，所有的染色体末端都附着在内核膜上（图1A）.这种附着依赖于端粒和SUN（Sad 1和JNK-84）-结构域蛋白之间的相互作用，SUN-结构域蛋白跨越内核膜，并且还与内核膜和外核膜之间的空间中的KASH（Klarsicht/ANC-1/Syne同源性）-结构域蛋白相互作用。KASH结构域蛋白跨越外核膜并与细胞骨架组分相互作用。端粒蛋白和SUN-和KASH-结构域蛋白在生物体中高度保守，并且它们中的大多数存在于有丝分裂和减数分裂中（Bhalla和Dernburg，2008）。此外，一些蛋白质（例如酿酒酵母中的Mps 3和Ndj 1，哺乳动物中的TERB 1和TERB 2）是减数分裂中特异性需要的（图1A; Zickler和Kleckner，1998年;在细线期/偶线期转换时，染色体末端移动到核膜上的有限区域（在哺乳动物中面向中心体，但在没有确定的中心体的植物中也形成花束），染色体被组织为具有成簇的端粒的花束。只有在减数分裂前期才能看到的独特的染色体组织称为花束（图1 B）。在大多数研究的生物体中观察到了气味（Zickler和Kleckner，1998; Zickler和Kleckner，2016; Bhalla和Dernburg，2008）。当同源物完全突触时，染色体末端逐渐重新分散，尽管仍然附着在核膜上（图1 B）。
Meiosis generates gametes with half the parental chromosome complements, and thus is crucial for successful sexual reproduction. During meiotic prophase I, a series of specialized events occur to ensure correct paternal and maternal homologous chromosomes (homologs) segregation during anaphase I. They include recognition, alignment, pairing and synapsis of the homologs and meiotic recombination which provides a link between homologs. During leptotene, all chromosome ends are attached to the inner nuclear membrane (Figure 1 A). This attachment depends on the interactions between telomeres and SUN (Sad1 and UNC-84)-domain proteins, which span the inner nuclear membrane and also interact with the KASH (Klarsicht/ANC-1/Syne homology)-domain proteins in the space between inner and outer nuclear membranes. The KASH domain proteins span the outer nuclear membrane and interact with cytoskeletal components. Telomeric proteins and SUN-and KASH-domain proteins are highly conserved among organisms and most of them are present in both mitosis and meiosis (Bhalla and Dernburg, 2008). Additionally, some proteins (eg Mps3 and Ndj1 in Saccharomyces cerevisiae, TERB1 and TERB2 in mammals) are specifically required in meiosis (Figure 1 A; Zickler and Kleckner, 1998; Bhalla and Dernburg, 2008).At the leptotene/zygotene transition, chromosome ends move to a limited area on the nuclear membrane (facing the centrosome in mammals, but bouquet also forms in plants without defined centrosome) and chromosomes are organized as a bouquet of flowers with clustered telomeres. The unique chromosome organization only seen during meiotic prophase is called as bouquet (Figure 1 B). Bouquet has been observed in most organisms studied (Zickler and Kleckner, 1998; Zickler and Kleckner, 2016; Bhalla and Dernburg, 2008). When homologs are fully synapsed, chromosome ends are gradually re-dispersed although still attached to the nuclear envelope (Figure 1 B).