Deposition of H2A.Z in chromatin is known to be mediated by a conserved SWR1 chromatin-remodeling complex in eukaryotes. However, little is known about whether and how the SWR1 complex cooperates with other chromatin regulators. Using immunoprecipitation followed by mass spectrometry, we found all known components of the Arabidopsis thaliana SWR1 complex and additionally identified the following three classes of previously uncharacterized plant-specific SWR1 components: MBD9, a methyl-CpG-binding domain-containing protein; CHR11 and CHR17 (CHR11/17), ISWI chromatin remodelers responsible for nucleosome sliding; and TRA1a and TRA1b, accessory subunits of the conserved NuA4 histone acetyltransferase complex. MBD9 directly interacts with CHR11/17 and the SWR1 catalytic subunit PIE1, and is responsible for the association of CHR11/17 with the SWR1 complex. MBD9, TRA1a, and TRA1b function as canonical components of the SWR1 complex to mediate H2A.Z deposition. CHR11/17 are not only responsible for nucleosome sliding but also involved in H2A.Z deposition. These results indicate that the association of the SWR1 complex with CHR11/17 may facilitate the coupling of H2A.Z deposition with nucleosome sliding, thereby co-regulating gene expression, development, and flowering time.

中文翻译：

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植物特定的SWR1染色质重塑复合物将组蛋白H2A.Z沉积与核小体滑动耦合在一起。

已知染色质中H2A.Z的沉积是由真核生物中保守的SWR1染色质重塑复合物介导的。然而，关于SWR1复合物是否以及如何与其他染色质调节剂协同作用的了解甚少。使用免疫沉淀然后进行质谱分析，我们发现了拟南芥SWR1复合物的所有已知成分，并另外鉴定了以下三类先前未表征的植物特异性SWR1成分：MBD9，一种含甲基CpG结合域的蛋白质；CHR11和CHR17（CHR11 / 17），ISWI染色质重塑剂，负责核小体滑动；和TRA1a和TRA1b是保守的NuA4组蛋白乙酰基转移酶复合物的辅助亚基。MBD9直接与CHR11 / 17和SWR1催化亚基PIE1相互作用，并负责将CHR11 / 17与SWR1复合体关联。MBD9，TRA1a和TRA1b作为SWR1配合物的规范成分来介导H2A.Z沉积。CHR11 / 17不仅负责核小体的滑动，还参与H2A.Z的沉积。这些结果表明，SWR1复合物与CHR11 / 17的缔合可能促进H2A.Z沉积与核小体滑动的耦合，从而共同调节基因的表达，发育和开花时间。