BIOGRID CURATED DATA FOR PUBLICATION: Combined Action of Histone Reader Modules Regulates NuA4 Local Acetyltransferase Function but Not Its Recruitment on the Genome.

Protein-Protein, Genetic, and Chemical Interactions for Steunou AL (2016):Combined Action of Histone Reader Modules Regulates NuA4 Local Acetyltransferase Function but Not Its Recruitment on the Genome. curated by BioGRID (https://thebiogrid.org); ABSTRACT: Recognition of histone marks by reader modules is thought to be at the heart of epigenetic mechanisms. These protein domains are considered to function by targeting regulators to chromosomal loci carrying specific histone modifications. This is important for proper gene regulation as well as propagation of epigenetic information. The NuA4 acetyltransferase complex contains two of these reader modules, an H3K4me3-specific plant homeodomain (PHD) within the Yng2 subunit and an H3K36me2/3-specific chromodomain in the Eaf3 subunit. While each domain showed a close functional interaction with the respective histone mark that it recognizes, at the biochemical level, genetic level (as assessed with epistatic miniarray profile screens), and phenotypic level, cells with the combined loss of both readers showed greatly enhanced phenotypes. Chromatin immunoprecipitation coupled with next-generation sequencing experiments demonstrated that the Yng2 PHD specifically directs H4 acetylation near the transcription start site of highly expressed genes, while Eaf3 is important downstream on the body of the genes. Strikingly, the recruitment of the NuA4 complex to these loci was not significantly affected. Furthermore, RNA polymerase II occupancy was decreased only under conditions where both PHD and chromodomains were lost, generally in the second half of the gene coding regions. Altogether, these results argue that methylated histone reader modules in NuA4 are not responsible for its recruitment to the promoter or coding regions but, rather, are required to orient its acetyltransferase catalytic site to the methylated histone 3-bearing nucleosomes in the surrounding chromatin, cooperating to allow proper transition from transcription initiation to elongation.

蛋白质-蛋白质、遗传和化学相互作用数据集，为 Steunou AL（2016）所著《组蛋白读取模块的联合作用调控 NuA4 本地乙酰转移酶功能，但不影响其在基因组上的招募》一文提供支持（https://thebiogrid.org）；摘要：组蛋白标记被读取模块识别被认为是表观遗传机制的核心。这些蛋白结构域被认为通过靶向携带特定组蛋白修饰的染色质位点来调节因子发挥作用。这对于正确的基因调控及表观遗传信息的传播至关重要。NuA4 乙酰转移酶复合物包含两个此类读取模块，Yng2 亚基中的 H3K4me3 特异性植物同源异形域（PHD）和 Eaf3 亚基中的 H3K36me2/3 特异性染色域。尽管每个结构域与其识别的相应组蛋白标记在功能上均表现出紧密的相互作用，但在生化水平、遗传水平（通过上位性小阵列分析筛选进行评估）以及表型水平上，同时缺失两个读取模块的细胞展现出显著增强的表型。染色质免疫沉淀结合下一代测序实验表明，Yng2 PHD 可特异性地引导 H4 乙酰化在高度表达基因的转录起始位点附近，而 Eaf3 在基因体下游发挥重要作用。引人注目的是，NuA4 复合物对这些位点的招募并未受到显著影响。此外，RNA 聚合酶 II 的结合仅在同时失去 PHD 和染色域的条件下降低，通常发生在基因编码区域的下半部分。总的来说，这些结果表明，NuA4 中的甲基化组蛋白读取模块并非其招募至启动子或编码区域的原因，而是需要将其乙酰转移酶催化位点定向至周围染色质中携带甲基化组蛋白 3 的核小体，协同作用以允许从转录起始到延伸的恰当过渡。