Emiliani S, Fischle W, Van Lint C, Al-Abed Y, Verdin E
Picower Institute for Medical Research, Manhasset, NY 11030, USA.
Proc Natl Acad Sci U S A. 1998 Mar 17;95(6):2795-800. doi: 10.1073/pnas.95.6.2795.
Histone acetylation levels in cells result from a dynamic equilibrium between competing histone acetylases and deacetylases. Changes in histone acetylation levels occur during both transcriptional activation and silencing. Cloning of the cDNA for a human histone deacetylase (HDAC1) has shown that it represents a human ortholog of the yeast transcriptional regulator RPD3. We have screened the expressed sequence tag database (National Center for Biotechnology Information) with the yeast RPD3 sequence and identified a human ortholog of RPD3, HDAC3. This cDNA encodes a protein of 428 amino acids with 58% sequence identity with HDAC1p. By using a specific polyclonal antiserum recognizing the C-terminal domain of HDAC3p and Western blotting, we detected a single approximately 49-kDa band in several tumor cell lines. HDAC3p is expressed predominantly in the nuclear compartment. Immunoprecipitation experiments with either an antiserum against HDAC3p or an anti-FLAG antiserum and a flagged HDAC3 cDNA showed that HDAc3p exhibits deacetylase activity both on free histones and on purified nucleosomes. This deacetylase activity is inhibited by trichostatin, trapoxin, and butyrate in vitro to the same degree as the deacetylase activity associated to HDAC1p. These observations identify another member of a growing family of human HDAC genes.
细胞中的组蛋白乙酰化水平是由竞争性的组蛋白乙酰转移酶和去乙酰化酶之间的动态平衡所决定的。在转录激活和沉默过程中，组蛋白乙酰化水平都会发生变化。人组蛋白去乙酰化酶（HDAC1）的cDNA克隆表明，它是酵母转录调节因子RPD3的人类同源物。我们用酵母RPD3序列筛选了表达序列标签数据库（美国国立生物技术信息中心），并鉴定出RPD3的人类同源物HDAC3。该cDNA编码一个428个氨基酸的蛋白质，与HDAC1p的序列同一性为58%。通过使用识别HDAC3p C末端结构域的特异性多克隆抗血清和蛋白质印迹法，我们在几种肿瘤细胞系中检测到一条单一的约49 kDa的条带。HDAC3p主要在细胞核区室中表达。用抗HDAC3p抗血清或抗FLAG抗血清以及带FLAG标签的HDAC3 cDNA进行免疫沉淀实验表明，HDAc3p对游离组蛋白和纯化的核小体都表现出去乙酰化酶活性。这种去乙酰化酶活性在体外被曲古抑菌素、 trapoxin和丁酸盐抑制的程度与HDAC1p相关的去乙酰化酶活性相同。这些观察结果确定了人类HDAC基因不断增加的家族中的另一个成员。
