Special characteristics of the transcription and splicing machinery in photoreceptor cells of the mammalian retina
Special characteristics of the transcription and splicing machinery in photoreceptor cells of the mammalian retina
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DOI：
10.1007/s00441-015-2204-x
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发表时间：
2015-11-01
影响因子：
3.6
通讯作者：
Dahlhaus, Regina
中科院分区：
文献类型：
--
作者：
Derlig, Kristin;Giessl, Andreas;Dahlhaus, Regina
染色质的组织和管理的转录和剪接是每个细胞的正确功能的基础，但特别是对于高活性细胞，如光感受器，视网膜的感觉神经元。最近的研究表明，与昼行动物的视杆细胞相比，夜行动物的视杆细胞具有倒置的染色质结构。异染色质集中在细胞核的中心，而具有遗传活性的常染色质则位于核膜附近。这种独特的染色质结构表明，转录和剪接机制也受到这些细胞中的特定适应。最近，我们描述了蛋白Simiate，这是丰富的核斑点，似乎参与转录和剪接过程。在这里，我们研究了小鼠视网膜神经元的Simiate和核斑点的分布。在内核和神经节细胞层的视网膜神经元中，Simiate以簇状模式集中在核内部，而在视杆和视锥感光细胞中，Simiate存在于核外围。用转录和剪接机制的标记物进一步染色证实了核斑点组分在外周的定位。比较夜间小鼠视网膜的核斑点的分布与白天的degu，我们发现在他们的感光细胞中的转录和剪接机器的安排没有差异，从而表明这些机器的组织是不相关的动物的生活方式，而是代表了感光组织和功能的一般特征。
Chromatin organization and the management of transcription and splicing are fundamental to the correct functioning of every cell but, in particular, for highly active cells such as photoreceptors, the sensory neurons of the retina. Rod photoreceptor cells of nocturnal animals have recently been shown to have an inverted chromatin architecture compared with rod photoreceptor cells of diurnal animals. The heterochromatin is concentrated in the center of the nucleus, whereas the genetically active euchromatin is positioned close to the nuclear membrane. This unique chromatin architecture suggests that the transcription and splicing machinery is also subject to specific adaptations in these cells. Recently, we described the protein Simiate, which is enriched in nuclear speckles and seems to be involved in transcription and splicing processes. Here, we examine the distribution of Simiate and nuclear speckles in neurons of mouse retinae. In retinal neurons of the inner nuclear and ganglion cell layer, Simiate is concentrated in a clustered pattern in the nuclear interior, whereas in rod and cone photoreceptor cells, Simiate is present at the nuclear periphery. Further staining with markers for the transcription and splicing machinery has confirmed the localization of nuclear speckle components at the periphery. Comparing the distribution of nuclear speckles in retinae of the nocturnal mouse with the diurnal degu, we found no differences in the arrangement of the transcription and splicing machinery in their photoreceptor cells, thus suggesting that the organization of these machineries is not related to the animal's lifestyle but rather represents a general characteristic of photoreceptor organization and function.