Nuclear import of histone H2A and H2B is mediated by a network of karyopherins.
Nuclear import of histone H2A and H2B is mediated by a network of karyopherins.
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DOI：
10.1083/jcb.153.2.251
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发表时间：
2001-04-16
期刊：
影响因子：
--
通讯作者：
Pemberton LF
中科院分区：
文献类型：
--
作者：
Mosammaparast N;Jackson KR;Guo Y;Brame CJ;Shabanowitz J;Hunt DF;Pemberton LF
新染色质组装的第一步是细胞周期调节的核心组蛋白的合成和核输入。核心组蛋白包括H_2A和H_2B，它们以异二聚体的形式组装成核小体。我们在这里表明，组蛋白H_2A和H_2B的输入是由核粘蛋白(KAP；Importin)家族的几个成员介导的。在胞质中检测到丰富的H_2A、H_2B和Kap114P的复合体。此外，还用H_2A和H_2B分离了另外两个Kap121p和Kap123p，以及组蛋白伴侣Nap1p。Nap1P对于Kap114P-H_2A/H_2B络合物的形成或H_2A和H_2B的进口不是必需的。我们证明这两个组蛋白在氨基末端尾部都含有一个核定位序列(NLS)。在KAP突变株中，NLSS与绿色荧光蛋白的融合被特异性地错位到细胞质中。此外，我们在Kap95温度敏感菌株中检测到特定的错误定位，表明该Kap也参与了体内H_2A和H_2B的输入。重要的是，我们发现Kap114p、Kap121p和Kap95直接与组蛋白NLSS相互作用，RanGTP抑制这种联系。这些数据表明，H_2A和H_2B的输入是由KAP网络介导的，Kap114P可能在其中起主要作用。
The first step in the assembly of new chromatin is the cell cycle–regulated synthesis and nuclear import of core histones. The core histones include H2A and H2B, which are assembled into nucleosomes as heterodimers. We show here that the import of histone H2A and H2B is mediated by several members of the karyopherin (Kap; importin) family. An abundant complex of H2A, H2B, and Kap114p was detected in cytosol. In addition, two other Kaps, Kap121p and Kap123p, and the histone chaperone Nap1p were isolated with H2A and H2B. Nap1p is not necessary for the formation of the Kap114p-H2A/H2B complex or for import of H2A and H2B. We demonstrate that both histones contain a nuclear localization sequence (NLS) in the amino-terminal tail. Fusions of the NLSs to green fluorescent protein were specifically mislocalized to the cytoplasm in kap mutant strains. In addition, we detected a specific mislocalization in a kap95 temperature-sensitive strain, suggesting that this Kap is also involved in the import of H2A and H2B in vivo. Importantly, we show that Kap114p, Kap121p, and Kap95 interact directly with both histone NLSs and that RanGTP inhibits this association. These data suggest that the import of H2A and H2B is mediated by a network of Kaps, in which Kap114p may play the major role.
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DOI：
10.1083/jcb.138.1.65
发表时间：
1997-07-14
期刊：
The Journal of cell biology
影响因子：
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作者：
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DOI：
10.1083/jcb.131.5.1133
发表时间：
1995-12
期刊：
The Journal of cell biology
影响因子：
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作者：
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