The absence of histone H2B monoubiquitination in the Arabidopsis hub1 (rdo4) mutant reveals a role for chromatin remodeling in seed dormancy
The absence of histone H2B monoubiquitination in the Arabidopsis hub1 (rdo4) mutant reveals a role for chromatin remodeling in seed dormancy
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DOI：
10.1105/tpc.106.049221
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发表时间：
2007-02-01
期刊：
影响因子：
11.6
通讯作者：
Soppe, Wim J. J.
中科院分区：
文献类型：
--
作者：
Liu, Yongxiu;Koornneef, Maarten;Soppe, Wim J. J.
种子休眠是指有活力的种子在适宜的条件下不能萌发。除了在自然界中通过优化发芽到最合适的时间来发挥适应作用外，严格控制休眠在作物中也是重要的。广泛的遗传学和生理学研究已经确定了几个因素的参与，但这一过程背后的分子机制在很大程度上仍不清楚。我们克隆了组蛋白MONOUBIQUITINATION1(HUB1)基因，该基因的突变体(以前被鉴定为简化休眠4)减少了种子休眠和几种多效性表型。HUB1编码C3HC4环指蛋白。拟南芥基因组包含一个HUB1同源基因，我们将其命名为HUB2。Hub2突变体也减少了种子休眠，并且与hub1没有冗余。HUB1和HUB2在其他物种中的同源物需要用于组蛋白H2B的单泛素化。与此一致的是，在hub1和hub2突变体中没有检测到泛素化形式的组蛋白H2B。在酵母和人类细胞中，组蛋白H_2B单泛素化与活跃转录的基因有关。Hub1突变体显示出几个休眠相关基因的表达水平发生了变化。我们提出了染色质重塑在通过HUB1和HUB2的H_2B单素化引起的种子休眠中的作用。
Seed dormancy is defined as the failure of a viable seed to germinate under favorable conditions. Besides playing an adaptive role in nature by optimizing germination to the most suitable time, a tight control of dormancy is important in crop plants. Extensive genetic and physiological studies have identified the involvement of several factors, but the molecular mechanisms underlying this process are still largely unknown. Wecloned the HISTONE MONOUBIQUITINATION1 (HUB1) gene, of which the mutant ( previously identified as reduced dormancy4) has reduced seed dormancy and several pleiotropic phenotypes. HUB1 encodes a C3HC4 RING finger protein. The Arabidopsis thaliana genome contains one HUB1 homolog, which we named HUB2. The hub2 mutant also has reduced seed dormancy and is not redundant with hub1. Homologs of HUB1 and HUB2 in other species are required for histone H2B monoubiquitination. In agreement with this, the ubiquitinated form of histone H2B could not be detected in the hub1 and hub2 mutants. In yeast and human cells, histone H2B monoubiquitination is associated with actively transcribed genes. The hub1 mutant showed altered expression levels for several dormancy-related genes. We propose a role for chromatin remodeling in seed dormancy by H2B monoubiquitination through HUB1 and HUB2.