Structure and function of the nucleus in DNA damage signaling and repair

从细菌到人类，所有生物的一个基本特性，就是通过修复DNA来纠正基因错误的能力。在多细胞生物中，DNA在细胞核中被发现与组蛋白包装形成染色质。当DNA被包装成染色质时，它的损伤更难以发现和修复。然而，染色质中的一种组蛋白被磷酸化（称为γ - h2a）。X)，标记用于DNA修复的染色质，并产生可以在光学显微镜下看到的点状斑点或灶。这些“修复病灶”被认为是在召唤修复DNA的酶。修复病灶有时与细胞核的特定亚区或结构域有关，如早幼粒细胞白血病核体（PML NB）和核层。尽管修复病灶在鉴定新的DNA修复因子方面非常有用，因为它们与γ - h2a共定位。X，我们几乎不知道它们的超微结构，也不知道它们的结构变化或在细胞核中的位置与DNA修复过程的关系。

A fundamental property of all living organisms from bacteria to humans, is the ability to correct genetic errors by repairing DNA. In multicellular organisms, DNA is found in the nucleus packaged with histone proteins to form chromatin. Damage to DNA is more difficult to find and repair when it is packaged into chromatin. However, one of the histone proteins in chromatin becomes phosphorylated (termed gamma-H2A.X), marking that chromatin for DNA repair and producing punctate spots or foci that can be seen with a light microscope. These "repair foci" are believed to act as beckons for the recruitment of enzymes that repair DNA. Repair foci are sometimes associated with particular sub-regions or domains of the nucleus such as the promyelocytic leukemia nuclear body (PML NB) and the nuclear lamina. Although repair foci have been immensely useful in the identification of novel DNA repair factors by virtue of their co-localisation with gamma-H2A.X, we know virtually nothing about their ultrastructure or how changes in their structure or location in the nucleus relate to the process of DNA repair.