Pathways mediating the nuclear import of histones H3 and H4 in yeast
Pathways mediating the nuclear import of histones H3 and H4 in yeast
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DOI：
10.1074/jbc.m106845200
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发表时间：
2002-01-04
影响因子：
4.8
通讯作者：
Pemberton, LF
中科院分区：
文献类型：
--
作者：
Mosammaparast, N;Guo, YR;Pemberton, LF
染色质的正确组装对于维持真核细胞中基因组的稳定性是必要的。新染色质组装的关键步骤是细胞周期调节的核心组蛋白的合成和核输入。在这里，我们证明了组蛋白H3和H4的核输入途径介导的至少两个karyopherinstimportins，Kap 123 p和Kap 121 p。发现胞质H4与Kap 123 p和H3相关。Kap 121 p也存在于H4-PrA相关组分中，尽管其量低于Kap 123 p，这表明该Kap作为额外的输入受体。我们进一步证明，胞质Kap 123 p，与乙酰化的H3和H4。H3和H4各自在其氨基末端结构域中含有核定位信号（NLS）。发现这些氨基末端结构域对于H3和H4-绿色荧光蛋白报告基因的核积累是必需的。每个NLS介导的直接结合Kap 123 p和Kap 121 p，并减少核积累的H3和H4 NLS-绿色荧光蛋白报告在特定的kap突变株观察。H3和H4是第一批组装到DNA上的组蛋白，这些结果表明它们的输入至少由两种输入途径介导。
The correct assembly of chromatin is necessary for the maintenance of genomic stability in eukaryotic cells. A critical step in the assembly of new chromatin is the cell cycle-regulated synthesis and nuclear import of core histones. Here we demonstrate that the nuclear import pathway of histones H3 and H4 is mediated by at least two karyopherinstimportins, Kap123p and Kap121p. Cytosolic H4 is found associated with Kap123p and H3. Kap121p is also present in the H4-PrA-associated fractions, albeit in lesser amounts than Kap123p, suggesting that this Kap serves as an additional import receptor. We further demonstrate that cytosolic Kap123p, is associated with acetylated H3 and H4. H3 and H4 each contain a nuclear localization signal (NLS) in their aminoterminal domains. These amino-terminal domains were found to be essential for the nuclear accumulation of H3 and H4-green fluorescent protein reporters. Each NLS mediated direct binding to Kap123p and Kap121p, and decreased nuclear accumulation of H3 and H4 NLS-green fluorescent protein reporters was observed in specific kap mutant strains. H3 and H4 are the first histones to be assembled onto DNA, and these results show that their import is mediated by at least two import pathways.