Epigenetics of eu- and heterochromatin in inverted and conventional nuclei from mouse retina
Epigenetics of eu- and heterochromatin in inverted and conventional nuclei from mouse retina
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DOI：
10.1007/s10577-013-9375-7
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发表时间：
2013-08-01
影响因子：
2.6
通讯作者：
Solovei, Irina
中科院分区：
文献类型：
--
作者：
Eberhart, Anja;Feodorova, Yana;Solovei, Irina
为了改善光通过视网膜的传播，夜间哺乳动物的视杆细胞核与其他细胞的细胞核相比发生了独特的变化。特别是，染色质的主要类别在它们中被分离，并按顺序形成规则的同心壳;与常规细胞核相比是倒置的。倒置和常规小鼠视网膜核的表观遗传景观的广泛研究表明它们之间的几个差异和哺乳动物细胞核组织的几个普遍感兴趣的功能。与常规结构的细胞核不同，在倒置的杆状细胞核中，着丝粒周围卫星和富含LINE的染色质的堆积密度相似;常染色质的堆积密度在两种情况下都较低。视杆细胞核中高度的染色质凝聚使活性和非活性X染色体同源物之间的结构差异最小化。DNA甲基化主要在染色中心，Dnmt 1主要与常染色质壳相关。异染色质蛋白HP 1-α和HP 1-β定位于异染色质壳，而HP 1-γ与常染色质相关。对于大多数的25个研究组蛋白修饰，我们观察到主要的共定位与一定的主染色质类。视杆细胞核中的倒位和常规细胞核中外周异染色质的维持都不受相应敲除小鼠中主要沉默核心组蛋白修饰的损失或耗尽的影响，但原因不同。外周异染色质的维持似乎是通过设置表观遗传密码（编写者）和密码本身的酶水平上的冗余来确保的，而视杆细胞中的倒位依赖于外周异染色质系链的缺失（没有密码阅读者）。
To improve light propagation through the retina, the rod nuclei of nocturnal mammals are uniquely changed compared to the nuclei of other cells. In particular, the main classes of chromatin are segregated in them and form regular concentric shells in order; inverted in comparison to conventional nuclei. A broad study of the epigenetic landscape of the inverted and conventional mouse retinal nuclei indicated several differences between them and several features of general interest for the organization of the mammalian nuclei. In difference to nuclei with conventional architecture, the packing density of pericentromeric satellites and LINE-rich chromatin is similar in inverted rod nuclei; euchromatin has a lower packing density in both cases. A high global chromatin condensation in rod nuclei minimizes the structural difference between active and inactive X chromosome homologues. DNA methylation is observed primarily in the chromocenter, Dnmt1 is primarily associated with the euchromatic shell. Heterochromatin proteins HP1-alpha and HP1-beta localize in heterochromatic shells, whereas HP1-gamma is associated with euchromatin. For most of the 25 studied histone modifications, we observed predominant colocalization with a certain main chromatin class. Both inversions in rod nuclei and maintenance of peripheral heterochromatin in conventional nuclei are not affected by a loss or depletion of the major silencing core histone modifications in respective knock-out mice, but for different reasons. Maintenance of peripheral heterochromatin appears to be ensured by redundancy both at the level of enzymes setting the epigenetic code (writers) and the code itself, whereas inversion in rods rely on the absence of the peripheral heterochromatin tethers (absence of code readers).