Lee Min Gyu, Wynder Christopher, Cooch Neil, Shiekhattar Ramin
The Wistar Institute, 3601 Spruce Street, Philadelphia, Pennsylvania 19104, USA.
Nature. 2005 Sep 15;437(7057):432-5. doi: 10.1038/nature04021. Epub 2005 Aug 3.
We have previously described a multiprotein complex termed the BHC or BRAF-HDAC complex, which is required for the repression of neuronal-specific genes. We have shown that the BHC complex is recruited by a neuronal silencer, REST (RE1-silencing transcription factor), and mediates the repression of REST-responsive genes. BHC is a multiprotein complex consisting of two enzymatic activities: a histone deacetylase (HDAC1 or 2) and a recently described histone demethylase (BHC110, also known as LSD1 or AOF2). Here we show that BHC110-containing complexes show a nearly fivefold increase in demethylation of histone H3 lysine 4 (H3K4) compared to recombinant BHC110. Furthermore, recombinant BHC110 is unable to demethylate H3K4 on nucleosomes, but BHC110-containing complexes readily demethylate nucleosomes. In vitro reconstitution of the BHC complex using recombinant subunits reveals an essential role for the REST corepressor CoREST, not only in stimulating demethylation on core histones but also promoting demethylation of nucleosomal substrates. We find that nucleosomal demethylation is the result of CoREST enhancing the association between BHC110 and nucleosomes. Depletion of CoREST in in vivo cell culture results in de-repression of REST-responsive gene expression and increased methylation of H3K4. Together, these results highlight an essential role for CoREST in demethylation of H3K4 both in vitro and in vivo.
我们之前描述过一种多蛋白复合物，称为BHC或BRAF - HDAC复合物，它是抑制神经元特异性基因所必需的。我们已经表明，BHC复合物是由神经元沉默因子REST（RE1 - 沉默转录因子）募集的，并介导REST反应性基因的抑制。BHC是一种多蛋白复合物，由两种酶活性组成：一种组蛋白去乙酰化酶（HDAC1或2）和一种最近描述的组蛋白去甲基化酶（BHC110，也称为LSD1或AOF2）。在这里我们表明，与重组BHC110相比，含有BHC110的复合物在组蛋白H3赖氨酸4（H3K4）的去甲基化方面显示出近五倍的增加。此外，重组BHC110无法使核小体上的H3K4去甲基化，但含有BHC110的复合物很容易使核小体去甲基化。使用重组亚基对BHC复合物进行体外重建揭示了REST共抑制因子CoREST的重要作用，不仅在刺激核心组蛋白的去甲基化方面，而且在促进核小体底物的去甲基化方面。我们发现核小体去甲基化是CoREST增强BHC110与核小体之间结合的结果。体内细胞培养中CoREST的缺失导致REST反应性基因表达的去抑制和H3K4甲基化的增加。总之，这些结果突出了CoREST在体外和体内H3K4去甲基化中的重要作用。
