Differential large-scale chromatin compaction and intranuclear positioning of transcribed versus non-transcribed transgene arrays containing β-globin regulatory sequences
Differential large-scale chromatin compaction and intranuclear positioning of transcribed versus non-transcribed transgene arrays containing β-globin regulatory sequences
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DOI：
10.1242/jcs.01330
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发表时间：
2004-09-01
影响因子：
4
通讯作者：
Belmont, AS
中科院分区：
文献类型：
--
作者：
Dietzel, S;Zolghadr, K;Belmont, AS
以前的工作已经证明了一个更去密集的大规模染色质结构和一个更内部的核位置的基因丰富与基因贫乏的染色体区域。在这里，我们表明，大规模的染色质开放和染色体区域的核内定位的变化可以诱导正常水平的内源性转录因子作用于哺乳动物的调控序列。我们转染小鼠红白血病细胞与一个15 kbp的质粒含有一个乳糖操纵基因重复加上β-珠蛋白调控序列驱动的β-半乳糖苷酶报告基因。在绿色荧光蛋白/乳糖阻遏物融合蛋白结合后或荧光原位杂交后，测量转基因阵列信号的体积和位置。这两种检测方法，我们发现，体积是几倍大时，转录on. While沉默的转基因阵列位于靠近核膜，我们观察到一个显着更多的内部位置的转录活性状态。我们的研究结果表明，大规模的染色质去凝聚和核定位的变化，观察到的大型，复杂的基因丰富的染色体区域可以复制内源性调控序列内简单的重复转基因阵列。
Previous work has demonstrated a more decondensed large-scale chromatin structure and a more internal nuclear position for gene-rich versus gene-poor chromosome regions. Here, we show that large-scale chromatin opening and changes in intranuclear positioning of chromosome regions can be induced by normal levels of endogenous transcription factors acting on mammalian regulatory sequences. We transfected mouse erythroleukemia cells with a 15 kbp plasmid containing a lac operator repeat plus beta-globin regulatory sequences driving a beta-galactosidase reporter gene. After green-fluorescent-protein/lac-repressor fusion-protein binding or after fluorescence in situ hybridization, the volume and location of the transgene array signal were measured. With both detection methods, we found that the volume was severalfold larger when transcription was on. While silent transgene arrays were located close to the nuclear membrane, we observed a significantly more internal position for the transcriptionally active state. Our results indicate that both large-scale chromatin decondensation and changes in nuclear positioning as observed for large, complex gene-rich chromosome regions can be reproduced by endogenous regulatory sequences acting within simple repetitive transgene arrays.