Replacement of Arabidopsis H2A.Z with human H2A.Z orthologs reveals extensive functional conservation and limited importance of the N-terminal tail sequence for Arabidopsis development (ChIP-Seq)

To investigate the functional conservation of H2A.Z histones during eukaryotic evolution we transformed h2a.z deficient plants with three human H2A.Z proteins to assess their ability to rescue the mutant defects. We discovered that human H2A.Z.1 and H2A.Z.2.1 fully complement the phenotypic abnormalities of h2a.z plants even though Arabidopsis and human H2A.Z N-terminal tail sequences are divergent, while the brain-specific splice variant H2A.Z.2.2 has a dominant-negative effect in wild-type plants. Furthermore, H2A.Z.1 almost completely re-establishes normal H2A.Z chromatin occupancy in h2a.z plants and restores the expression of more than 84 % of misexpressed genes. Finally, our hypothesis that the N-terminal tail of Arabidopsis H2A.Z is not crucial for its overall function was supported by the ability of N-terminal end truncations of Arabidopsis HTA11 to largely rescue the defects of h2a.z mutants. Overall design: ChIPseq on biological duplicates of WT, h2a.z + AtHTA11, and h2a.z + HsH2A.Z.1 Arabidopsis leaf tissue (third and/or fourth pair of rosette leaves)

为探究真核生物演化过程中组蛋白H2A.Z（H2A.Z）的功能保守性，本研究采用三种人类H2A.Z蛋白转化H2A.Z缺陷型拟南芥植株，以评估其挽救该突变体缺陷的能力。本研究发现，尽管拟南芥与人类H2A.Z的N端尾序列存在显著差异，但人类H2A.Z.1与H2A.Z.2.1可完全互补h2a.z缺陷型植株的表型异常；而脑特异性剪接变体H2A.Z.2.2在野生型植株中表现出显性负效应。此外，H2A.Z.1可几乎完全恢复h2a.z缺陷型植株中正常的H2A.Z染色质结合占有率，并恢复超过84%的异常表达基因的表达水平。最后，拟南芥HTA11的N端截短体可大幅挽救h2a.z突变体的缺陷，这一结果验证了我们的假说：拟南芥H2A.Z的N端尾对其整体功能并非必需。实验整体设计：对野生型（WT）、h2a.z缺陷型+AtHTA11、h2a.z缺陷型+HsH2A.Z.1的拟南芥叶片组织（第三对/第四对莲座叶）的生物学重复样本进行染色质免疫共沉淀测序（ChIP-seq）。