An early developmental transcription factor complex that is more stable on nucleosome core particles than on free DNA
An early developmental transcription factor complex that is more stable on nucleosome core particles than on free DNA
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DOI：
10.1016/s1097-2765(00)80225-7
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发表时间：
1999-12-01
期刊：
影响因子：
16
通讯作者：
Zaret, KS
中科院分区：
文献类型：
--
作者：
Cirillo, LA;Zaret, KS
体内足迹研究表明，在肝脏基因转录的发育激活之前，HNF 3和加塔-4的转录因子结合位点被占据在胚胎内胚层中的白蛋白基因增强子上。我们已经研究了这些因子如何稳定地占据沉默的染色质。值得注意的是，我们发现HNF 3，而不是加塔-4或GAL 4对照蛋白，与核小体核心颗粒的结合比游离DNA稳定得多。在存在HNF 3的情况下，加塔-4稳定地结合至位于HNF 3的核小体。组蛋白乙酰化不影响HNF 3结合。这是转录因子与核小体稳定结合的证据，并表明有翼螺旋蛋白足以启动非乙酰化核小体上增强子复合物的组装。
In vivo footprinting studies have shown that transcription factor binding sites for HNF3 and GATA-4 are occupied on the albumin gene enhancer in embryonic endoderm, prior to the developmental activation of liver gene transcription. We have investigated how these factors can stably occupy silent chromatin. Remarkably, we find that HNF3, but not GATA-4 or a GAL4 control protein, binds far more stably to nucleosome core particles than to free DNA. In the presence of HNF3, GATA-4 binds stably to an HNF3-positioned nucleosome. Histone acetylation does not affect HNF3 binding. This is evidence for stable nucleosome binding by a transcription factor and shows that a winged helix protein is sufficient to initiate the assembly of an enhancer complex on nonacetylated nucleosomes.