Mazina M Iu, Vorob'eva N E, Krasnov A N
Tsitologiia. 2013;55(4):218-24.
DNA replication begins from multiple sites distributed thoughout the genome and named replication origins. Despite the increasing amount of data on the properties of replication origins, it is still unknown what factors(s) is the primary determinant of ORC localization. Su(Hw) is a zinc-finger protein that is responsible for the activity of the best-studied Drosophila insulators. Here, we show that insulator protein Su(Hw) recruits histone acetyltransferase complex SAGA and chromatin remodeler dSWI/SNF to Su(Hw)-dependent insulators and creates platform for ORC binding. We have found that Su(Hw) is necessary for chromatin remodeling and ORC recruitment regardless of type of surrounding chromatin. Thus, global chromatin state does not influence molecular mechanism underlying ORC positioning in the genome, rather DNA-binding proteins are key determinants that create proper chromatin structure for ORC binding. Su(Hw) is the first example of such a protein.
DNA复制起始于基因组中分布的多个位点，这些位点被称为复制起点。尽管关于复制起点特性的数据越来越多，但仍不清楚哪些因素是ORC定位的主要决定因素。Su(Hw)是一种锌指蛋白，负责研究得最透彻的果蝇绝缘子的活性。在这里，我们表明绝缘子蛋白Su(Hw)将组蛋白乙酰转移酶复合物SAGA和染色质重塑因子dSWI/SNF招募到依赖于Su(Hw)的绝缘子上，并为ORC结合创造平台。我们发现，无论周围染色质的类型如何，Su(Hw)对于染色质重塑和ORC招募都是必需的。因此，整体染色质状态并不影响基因组中ORC定位的分子机制，相反，DNA结合蛋白是为ORC结合创造适当染色质结构的关键决定因素。Su(Hw)就是这类蛋白的首个例子。
