Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA.
J Biol Chem. 2012 Mar 30;287(14):10753-60. doi: 10.1074/jbc.M112.347450. Epub 2012 Feb 15.
The yeast histone chaperone Rtt106 is involved in de novo assembly of newly synthesized histones into nucleosomes during DNA replication and plays a role in regulating heterochromatin silencing and maintaining genomic integrity. The interaction of Rtt106 with H3-H4 is modulated by acetylation of H3 lysine 56 catalyzed by the lysine acetyltransferase Rtt109. Using affinity purification strategies, we demonstrate that Rtt106 interacts with (H3-H4)(2) heterotetramers in vivo. In addition, we show that Rtt106 undergoes homo-oligomerization in vivo and in vitro, and mutations in the N-terminal homodimeric domain of Rtt106 that affect formation of Rtt106 oligomers compromise the function of Rtt106 in transcriptional silencing and response to genotoxic stress and the ability of Rtt106 to bind (H3-H4)(2). These results indicate that Rtt106 deposits H3-H4 heterotetramers onto DNA and provide the first description of a H3-H4 chaperone binding to (H3-H4)(2) heterotetramers in vivo.
酵母组蛋白伴侣 Rtt106 参与 DNA 复制过程中新合成组蛋白从头组装到核小体中，在调节异染色质沉默和维持基因组完整性方面发挥作用。Rtt106 与 H3-H4 的相互作用受赖氨酸乙酰转移酶 Rtt109 催化的 H3 赖氨酸 56 乙酰化调节。我们使用亲和纯化策略证明 Rtt106 在体内与 (H3-H4)(2) 异四聚体相互作用。此外，我们还表明 Rtt106 在体内和体外发生同源寡聚化，并且影响 Rtt106 寡聚体形成的 Rtt106 N 端同源二聚结构域突变会损害 Rtt106 在转录沉默和对遗传毒性应激的反应中的功能，以及 Rtt106 结合 (H3-H4)(2) 的能力。这些结果表明 Rtt106 将 H3-H4 异四聚体沉积到 DNA 上，并首次描述了一种 H3-H4 伴侣在体内与 (H3-H4)(2) 异四聚体结合。
