Investigation of the properties of non-gypsy Suppressor of Hairy-wing-binding sites
Investigation of the properties of non-gypsy Suppressor of Hairy-wing-binding sites
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DOI：
10.1534/genetics.108.087254
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发表时间：
2008-07-01
期刊：
影响因子：
3.3
通讯作者：
Geyer, Pamela K.
中科院分区：
文献类型：
--
作者：
Kuhn-Parnell, Emily J.;Helou, Cecilia;Geyer, Pamela K.
绝缘子定义了真核基因组中转录调控元件之间的相互作用。在吉普赛逆转录病毒中发现的吉普赛绝缘体结合了毛翼[SU(HW)]蛋白的锌指抑制蛋白，该蛋白与整个果蝇基因组中非吉普赛区域的背部相关联。绝缘体功能模型预测，吉普赛绝缘体通过与内源性SU(HW)绝缘体(SIS)相互作用形成染色质环域，以限制转录调控元件的作用。在这里，我们研究了SI 62d，并表明在两个SI 62d元件之间发生干扰，但在SI 62d和吉普赛绝缘子之间不发生干扰，从而限制了基因组吉普赛绝缘子相互作用的范围。被SI 62d阻断的增强子需要比sypsy绝缘体功能所需的更少的SU(HW)结合位点，这些靶区对体内SU(HW)结合具有不同的锌指要求。这些观察结果导致了对SU(HW)锌指结构域在绝缘体功能中的作用的研究。采用体外和体内研究相结合的方法，我们发现该结构域在体内染色体关联中起着序列依赖和独立的作用，但对增强子或沉默因子的阻断并不是必需的。这些研究扩大了我们对SU(HW)的性质以及该蛋白所定位的内源基因组区域的理解。
Insulators define interactions between transcriptional control elements in eukaryotic genomes. The gypsy insulator found in the gypsy retrovirus binds the zinc-finger Suppressor of Hairy-wing [Su(Hw)] protein that associates with hunderds of non-gypsy regions throughout the Drosophila genome. Models of insulator function predict that the gypsy insulator forms chromatin loop domains through interactions with endogenous Su(Hw) insulators (SIs) to limit the action of trascriptional control elements. Here we study SI 62D and show that interractions occur between two SI 62D elements, but not between SI 62D and the gypsy insulator, limiting the scope of genomic gypsy insulator interactions. Enhancer blocking by SI 62D requires fewer Su(Hw)-binding sites than needed for sypsy insulator function, with these target regions having distinct zinc-finger requirements for in vivo Su(Hw) association. These observations led to an investigation of the role of the Su(Hw) zinc-finger domain in insulator function. Using a combination of in vitro and in vivo studies, we find that this domain makes sequence-dependent and -independent contributions in vivo chromosome association, but is not essential for enhancer or silencer blocking. These studies extend our understanding of the properties of Su(Hw) and the endogenous genomic regions to which this protein localizes.