Dou Yali, Milne Thomas A, Tackett Alan J, Smith Edwin R, Fukuda Aya, Wysocka Joanna, Allis C David, Chait Brian T, Hess Jay L, Roeder Robert G
Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, New York 10021, USA.
Cell. 2005 Jun 17;121(6):873-85. doi: 10.1016/j.cell.2005.04.031.
A stable complex containing MLL1 and MOF has been immunoaffinity purified from a human cell line that stably expresses an epitope-tagged WDR5 subunit. Stable interactions between MLL1 and MOF were confirmed by reciprocal immunoprecipitation, cosedimentation, and cotransfection analyses, and interaction sites were mapped to MLL1 C-terminal and MOF zinc finger domains. The purified complex has a robust MLL1-mediated histone methyltransferase activity that can effect mono-, di-, and trimethylation of H3 K4 and a MOF-mediated histone acetyltransferase activity that is specific for H4 K16. Importantly, both activities are required for optimal transcription activation on a chromatin template in vitro and on an endogenous MLL1 target gene, Hox a9, in vivo. These results indicate an activator-based mechanism for joint MLL1 and MOF recruitment and targeted methylation and acetylation and provide a molecular explanation for the closely correlated distribution of H3 K4 methylation and H4 K16 acetylation on active genes.
一种包含MLL1和MOF的稳定复合物已从稳定表达表位标签化WDR5亚基的人类细胞系中通过免疫亲和纯化得到。通过相互免疫沉淀、共沉降和共转染分析证实了MLL1和MOF之间的稳定相互作用，并将相互作用位点定位到MLL1的C末端和MOF的锌指结构域。纯化的复合物具有强大的MLL1介导的组蛋白甲基转移酶活性，可实现H3 K4的单甲基化、二甲基化和三甲基化，以及MOF介导的对H4 K16具有特异性的组蛋白乙酰转移酶活性。重要的是，这两种活性对于体外染色质模板上以及体内内源性MLL1靶基因Hox a9上的最佳转录激活都是必需的。这些结果表明了一种基于激活剂的机制，用于联合招募MLL1和MOF以及靶向甲基化和乙酰化，并为活性基因上H3 K4甲基化和H4 K16乙酰化的紧密相关分布提供了分子解释。
