a Department of Biology, College of Staten Island, City University of New York, 2800 Victory Blvd., Staten Island, NY 10314, USA.
Biochem Cell Biol. 2014 Feb;92(1):69-75. doi: 10.1139/bcb-2013-0097. Epub 2013 Nov 27.
In yeast, Ace1p-dependent induction of CUP1 is responsible for protecting cells from copper toxicity. Although the mechanism of yeast CUP1 induction has been studied intensively, it is still uncertain which chromatin remodelers are involved in CUP1 transcriptional activation. Here, we show that yeast cells are inviable in the presence of copper when either chromatin remodeler, Ino80p or Snf2p, is not present. This inviability is due to the lack of CUP1 expression in ino80Δ and snf2Δ cells. Subsequently, we observe that both Ino80p and Snf2p are present at the promoter and they are responsible for recruiting chromatin remodeling activity to the CUP1 promoter under induced conditions. These results suggest that they directly participate in CUP1 transcriptional activation. Furthermore, the codependent recruitment of both INO80 and SWI/SNF depends on the presence of the transcriptional activator, Ace1p. We also demonstrate that both remodelers are required to recruit RNA polymerase II and targeted histone acetylation, indicating that remodelers are recruited to the CUP1 promoter before RNA polymerase II and histone acetylases. These observations provide evidence for the mechanism of CUP1 induction. As such, we propose a model that describes novel insight into the order of events in CUP1 activation.
在酵母中，Ace1p 依赖性诱导 CUP1 负责保护细胞免受铜毒性。尽管已经对酵母 CUP1 诱导的机制进行了深入研究，但仍不确定哪些染色质重塑剂参与了 CUP1 的转录激活。在这里，我们表明，当不存在染色质重塑因子 Ino80p 或 Snf2p 时，酵母细胞在存在铜的情况下无法存活。这种不存活是由于 ino80Δ 和 snf2Δ 细胞中缺乏 CUP1 表达。随后，我们观察到 Ino80p 和 Snf2p 都存在于启动子上，并且它们负责在诱导条件下将染色质重塑活性募集到 CUP1 启动子上。这些结果表明它们直接参与 CUP1 的转录激活。此外，INO80 和 SWI/SNF 的共依赖性募集依赖于转录激活因子 Ace1p 的存在。我们还证明了这两种重塑因子都需要募集 RNA 聚合酶 II 和靶向组蛋白乙酰化，表明重塑因子在 RNA 聚合酶 II 和组蛋白乙酰转移酶之前被募集到 CUP1 启动子上。这些观察结果为 CUP1 诱导的机制提供了证据。因此，我们提出了一个模型，描述了 CUP1 激活过程中事件顺序的新见解。
