A CAF-1 dependent pool of HP1 during heterochrornatin duplication
A CAF-1 dependent pool of HP1 during heterochrornatin duplication
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DOI：
10.1038/sj.emboj.7600362
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发表时间：
2004-09-01
期刊：
影响因子：
11.4
通讯作者：
Almouzni, G
中科院分区：
文献类型：
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作者：
Quivy, JP;Roche, D;Almouzni, G
为了研究异染色质的复杂组织是如何在每个复制周期中复制的，我们研究了小鼠细胞中富含HP 1的臂间区的命运。我们发现，复制主要发生在这些领域的PCNA和染色质组装因子1（CAF-1）位于表面。结合高分辨率分析和3D建模的脉冲追踪实验表明，在90分钟内，新复制的DNA在结构域内部被内化。值得注意的是，在这段时间内，与CAF-1和复制位点一致的特定HP 1分子亚组（α和γ）对RNA酶处理具有抗性。此外，这些复制相关的HP 1分子检测Suv 39敲除细胞，否则缺乏稳定的HP 1染色在臂间异染色质。在p150 CAF-1 siRNA处理后，HP 1分子的复制池完全消失。我们的结论是，在复制过程中，HP 1与p150 CAF-1的相互作用是必不可少的，以促进HP 1分子的异染色质位点，在那里他们随后保留进一步与甲基化H3-K9和RNA的相互作用。
To investigate how the complex organization of heterochromatin is reproduced at each replication cycle, we examined the fate of HP1-rich pericentric domains in mouse cells. We find that replication occurs mainly at the surface of these domains where both PCNA and chromatin assembly factor 1 (CAF-1) are located. Pulse-chase experiments combined with high-resolution analysis and 3D modeling show that within 90 min newly replicated DNA become internalized inside the domain. Remarkably, during this time period, a specific subset of HP1 molecules (alpha and gamma) coinciding with CAF-1 and replicative sites is resistant to RNase treatment. Furthermore, these replication-associated HP1 molecules are detected in Suv39 knockout cells, which otherwise lack stable HP1 staining at pericentric heterochromatin. This replicative pool of HP1 molecules disappears completely following p150CAF-1 siRNA treatment. We conclude that during replication, the interaction of HP1 with p150CAF-1 is essential to promote delivery of HP1 molecules to heterochromatic sites, where they are subsequently retained by further interactions with methylated H3-K9 and RNA.