SWITCH1 (SWI1):: a novel protein required for the establishment of sister chromatid cohesion and for bivalent formation at meiosis
SWITCH1 (SWI1):: a novel protein required for the establishment of sister chromatid cohesion and for bivalent formation at meiosis
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DOI：
10.1101/gad.203201
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发表时间：
2001-07-15
影响因子：
10.5
通讯作者：
Horlow, C
中科院分区：
文献类型：
--
作者：
Mercier, R;Vezon, D;Horlow, C
我们已经鉴定了一个新基因SWI 1，该基因参与拟南芥雄性和雌性减数分裂期间姐妹染色单体的凝聚。第一个等位基因swi1.1是作为T-DNA标记的突变体获得的，并且先前被描述为仅在女性减数分裂中异常。我们已经分离出一个新的等位基因，swi1.2，这是有缺陷的男性和女性减数分裂。在swi1.2雄性减数分裂中，没有观察到前期的经典步骤，特别是因为同源物不突触。染色单体臂和着丝粒在中期Ⅰ前逐渐失去凝聚力，在中期板上观察到20个染色单体而不是5个二价体，随后出现异常分离。相反，swi1.2雌性性母细胞进行有丝分裂，而不是减数分裂，表明SWI 1的不同作用或SWI 1功能的丧失在这两个过程中的不同影响。SWI 1基因被克隆，推定的SWI 1蛋白没有表现出强烈的相似性，任何已知的蛋白质。用SWI 1-GFP融合物转化的植物表明，SWI 1蛋白存在于性母细胞核中，在减数分裂之前和在前期的非常早期阶段。因此，SWI 1似乎是一种新的蛋白质参与染色单体凝聚力的建立和减数分裂过程中的染色体结构，但男性和女性减数分裂之间有明显的差异。
We have characterized a new gene, SWI1, involved in sister chromatid cohesion during both male and female meiosis in Arabidopsis thaliana. A first allele, swi1.1, was obtained as a T-DNA tagged mutant and was described previously as abnormal exclusively in female meiosis. We have isolated a new allele, swi1.2, which is defective for both male and female meiosis. In swi1.2 male meiosis, the classical steps of prophase were not observed, especially because homologs do not synapse. Chromatid arms and centromeres lost their cohesion in a stepwise manner before metaphase I, and 20 chromatids instead of five bivalents were seen at the metaphase plate, which was followed by an aberrant segregation. In contrast, swi1.2 female meiocytes performed a mitotic-like division instead of meiosis, indicating a distinct role for SWI1 or a different effect of the loss of SWI1 function in both processes. The SWI1 gene was cloned; the putative SWI1 protein did not show strong similarity to any known protein. Plants transformed with a SWI1-GFP fusion indicated that SWI1 protein is present in meiocyte nuclei, before meiosis and at a very early stage of prophase. Thus, SWI1 appears to be a novel protein involved in chromatid cohesion establishment and in chromosome structure during meiosis, but with clear differences between male and female meiosis.