Different genetic functions for the Rpd3(L) and Rpd3(S) complexes suggest competition between NuA4 and Rpd3(S)
Different genetic functions for the Rpd3(L) and Rpd3(S) complexes suggest competition between NuA4 and Rpd3(S)
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DOI：
10.1128/mcb.00164-08
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发表时间：
2008-07-01
影响因子：
5.3
通讯作者：
Stillman, David J.
中科院分区：
文献类型：
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作者：
Biswas, Debabrata;Takahata, Shinya;Stillman, David J.
Rpd3(L) 和 Rpd3(S) 是包含 Rpd3 组蛋白脱乙酰酶的不同多亚基复合物。当与仅影响 Rpd3(L) 复合体的 sds3 突变或仅影响 Rpd3(S) 的 rco1 突变结合时，GCN5 组蛋白乙酰转移酶基因的破坏显示出强烈的合成表型。然而，在 gcn5 sds3 rco1 三重突变体中没有看到这些合成生长缺陷，这表明 Rpd3(L) 和 Rpd3(S) 之间的平衡对于缺乏 Gcn5 的细胞至关重要。不同的遗传相互作用与影响 FACT 染色质重组复合体的突变有关。仅影响 Rpd3(L) 的 sds3 突变具有 FACT 突变体的合成缺陷，而影响 Rpd3(S) 的 rco1 和 eaf3 突变抑制 FACT 突变体表型。因此，Rpd3(L) 与 FACT 一致，但 Rpd3(S) 反对。将 FACT 突变与 NuA4 组蛋白乙酰转移酶 Esa1 亚基突变相结合会导致合成生长缺陷，而这些缺陷可以通过 rco1 或 set2 突变来抑制。 rco1 突变会抑制 NuA4 的 ESA1 和 ARP4 亚基突变引起的表型，而 Rco1 过表达会加剧这些缺陷。这些结果提出了 NuA4 和 Rpd3(S) 竞争的模型。染色质免疫沉淀实验表明，消除 Rpd3(S) 会增加转录激活过程中 NuA4 与 ARG3 启动子的结合量以及与双链断裂诱导的 DNA 修复位点的结合量。我们的结果表明，Rpd3(L) 和 Rpd3(S) 复合物在体内具有不同的功能，并且两种形式的相对量会改变其他染色质改变复合物（例如 FACT 和 NuA4）的有效性。
Rpd3(L) and Rpd3(S) are distinct multisubunit complexes containing the Rpd3 histone deacetylase. Disruption of the GCN5 histone acetyltransferase gene shows a strong synthetic phenotype when combined with either an sds3 mutation affecting only the Rpd3(L) complex or an rco1 mutation affecting only Rpd3(S). However, these synthetic growth defects are not seen in a gcn5 sds3 rco1 triple mutant, suggesting that the balance between Rpd3(L) and Rpd3(S) is critical in cells lacking Gcn5. Different genetic interactions are seen with mutations affecting the FACT chromatin reorganizing complex. An sds3 mutation affecting only Rpd3(L) has a synthetic defect with FACT mutants, while rco1 and eaf3 mutations affecting Rpd3(S) suppress FACT mutant phenotypes. Rpd3(L) therefore acts in concert with FACT, but Rpd3(S) opposes it. Combining FACT mutations with mutations in the Esa1 subunit of the NuA4 histone acetyltransferase results in synthetic growth defects, and these can be suppressed by an rco1 or set2 mutation. An rco1 mutation suppresses phenotypes caused by mutations in the ESA1 and ARP4 subunits of NuA4, while Rco1 overexpression exacerbates these defects. These results suggest a model in which NuA4 and Rpd3(S) compete. Chromatin immunoprecipitation experiments show that eliminating Rpd3(S) increases the amount of NuA4 binding to the ARG3 promoter during transcriptional activation and to the sites of DNA repair induced by a double-strand break. Our results suggest that the Rpd3(L) and Rpd3(S) complexes have distinct functions in vivo and that the relative amounts of the two forms alter the effectiveness of other chromatin-altering complexes, such as FACT and NuA4.