Li Bing, Gogol Madelaine, Carey Mike, Lee Daeyoup, Seidel Chris, Workman Jerry L
Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA.
Science. 2007 May 18;316(5827):1050-4. doi: 10.1126/science.1139004.
Nucleosomes must be deacetylated behind elongating RNA polymerase II to prevent cryptic initiation of transcription within the coding region. RNA polymerase II signals for deacetylation through the methylation of histone H3 lysine 36 (H3K36), which provides the recruitment signal for the Rpd3S histone deacetylase complex (HDAC). The recognition of methyl H3K36 by Rpd3S requires the chromodomain of its Eaf3 subunit. Paradoxically, Eaf3 is also a subunit of the NuA4 acetyltransferase complex, yet NuA4 does not recognize methyl H3K36 nucleosomes. In Saccharomyces cerevisiae, we found that methyl H3K36 nucleosome recognition by Rpd3S also requires the plant homeobox domain (PHD) of its Rco1 subunit. Thus, the coupled chromo and PHD domains of Rpd3S specify recognition of the methyl H3K36 mark, demonstrating the first combinatorial domain requirement within a protein complex to read a specific histone code.
核小体必须在延伸的RNA聚合酶II之后去乙酰化，以防止编码区内转录的隐蔽起始。RNA聚合酶II通过组蛋白H3赖氨酸36（H3K36）的甲基化发出去乙酰化信号，这为Rpd3S组蛋白去乙酰化酶复合物（HDAC）提供了招募信号。Rpd3S对甲基化H3K36的识别需要其Eaf3亚基的色域。矛盾的是，Eaf3也是NuA4乙酰转移酶复合物的一个亚基，但NuA4不识别甲基化H3K36核小体。在酿酒酵母中，我们发现Rpd3S对甲基化H3K36核小体的识别还需要其Rco1亚基的植物同源结构域（PHD）。因此，Rpd3S的色域和PHD结构域共同决定了对甲基化H3K36标记的识别，这证明了蛋白质复合物中第一个读取特定组蛋白密码所需的组合结构域要求。
