The Rice OsRad21-4, an Orthologue of Yeast Rec8 Protein, is Required for Efficient Meiosis
The Rice OsRad21-4, an Orthologue of Yeast Rec8 Protein, is Required for Efficient Meiosis
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DOI：
10.1007/s11103-005-4922-z
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发表时间：
2006-03
影响因子：
5.1
通讯作者：
Liangran Zhang;Jiayi Tao;Shunxin Wang;K. Chong;Tai Wang
中科院分区：
文献类型：
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作者：
Liangran Zhang;Jiayi Tao;Shunxin Wang;K. Chong;Tai Wang
在酵母中，Rad 21/Scc 1及其减数分裂变体Rec 8分别是有丝分裂和减数分裂姐妹染色单体凝聚力建立和随后溶解的关键参与者，这对染色体分离至关重要。与酵母不同，我们的鉴定揭示了水稻基因组具有4个RAD 21样基因，这些基因在多肽水平上的同一性低于21%，并且每个基因在该基因组中以单拷贝存在。在此，我们利用RNAi技术对OsRAD 21 - 4的功能进行了分析。蛋白质印迹分析表明，该蛋白质在幼花中含量最高，在叶和芽中含量较少，而在根中不存在。在花中，该表达进一步定义为减数分裂前的花粉母细胞（PMCs）和花药减数分裂的PMCs。利用RNAi技术对OsRAD 21 -4基因缺失株系的雄性减数分裂染色体行为进行了监测。在减数分裂前期Ⅰ，雄性母细胞出现了多个异常现象，包括染色体的过度浓缩、同源物的早熟分离和染色体断裂。原位杂交结果表明，缺失株系在姐妹染色单体臂上的同源配对和凝聚力都有缺陷。这些缺陷导致染色体不均等分离和异常孢子产生。这些观察结果表明OsRad 21 -4对于有效的减数分裂是必需的。
In yeast, Rad21/Scc1 and its meiotic variant Rec8 are key players in the establishment and subsequent dissolution of sister chromatid cohesion for mitosis and meiosis, respectively, which are essential for chromosome segregation. Unlike yeast, our identification revealed that the rice genome has 4RAD21-like genes that share lower than 21% identity at polypeptide levels, and each is present as a single copy in this genome. Here we describe our analysis of the function ofOsRAD21-4by RNAi. Western blot analyses indicated that the protein was most abundant in young flowers and less in leaves and buds but absent in roots. In flowers, the expression was further defined to premeiotic pollen mother cells (PMCs) and meiotic PMCs of anthers. Meiotic chromosome behaviors were monitored from male meiocytes of OsRAD21-4-deficient lines mediated by RNAi. The male meiocytes showed multiple aberrant events at meiotic prophase I, including over-condensation of chromosomes, precocious segregation of homologues and chromosome fragmentation. Fluorescencein situhybridization experiments revealed that the deficient lines were defective in homologous pairing and cohesion at sister chromatid arms. These defects resulted in unequal chromosome segregation and aberrant spore generation. These observations suggest that OsRad21-4 is essential for efficient meiosis.