DEPLETION OF HISTONE-H4 AND NUCLEOSOMES ACTIVATES THE PHO5 GENE IN SACCHAROMYCES-CEREVISIAE
DEPLETION OF HISTONE-H4 AND NUCLEOSOMES ACTIVATES THE PHO5 GENE IN SACCHAROMYCES-CEREVISIAE
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DOI：
10.1002/j.1460-2075.1988.tb03061.x
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发表时间：
1988-07-01
期刊：
影响因子：
11.4
通讯作者：
GRUNSTEIN, M
中科院分区：
文献类型：
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作者：
HAN, M;KIM, UJ;GRUNSTEIN, M
我们之前构建了一种酵母菌株（UKY403），其唯一的组蛋白 H4 基因受 GAL1 启动子控制。由于组蛋白 H4 耗尽，这种酵母在葡萄糖处理后停滞在 G2 期。酵母 PH05 基因包含相核小体，其覆盖处于 PH05 抑制状态的启动子 (UAS) 序列，并且有人建议核小体阻止正作用因子与这些 UAS 序列的结合。使用 UKY403，我们通过使用微球菌核酸酶和间接末端标记检查了 PH05 上游区域中多核小体的长度和核小体定相。研究发现，葡萄糖停滞导致 PH05 染色质结构严重破坏，并且大多数核小体的位置发生改变或从 PH05 启动子区域丢失。即使在抑制性、高无机磷酸盐条件下，经历核小体耗竭的细胞也能合成大量准确的 PH05 转录本。组蛋白 H4 耗尽似乎不会影响另一个诱导型酵母基因 CUP1 的抑制或激活。在 G1 早期（在细胞分裂周期突变体 cdc28 中）或在 G2 的各个阶段（在 cdc15、cdc17 和 cdc20 中）具有里程碑意义的逮捕不会激活 PH05；也不会因染色体拓扑变化（在top2或top1top2拓扑异构酶突变体中）而停滞。 cdc14 在细胞周期中与 cdc15 相似的点上有其阻滞标志，它确实会去抑制 PH05。然而，由于它也会导致 CUP1 的去抑制，因此它可能通过独立的机制发挥作用。因此，我们的数据表明核小体调节 PH05 转录。
We have previously constructed a yeast strain (UKY403) whose sole histone H4 gene is under control of the GAL1 promoter. This yeast arrests in G2 upon glucose treatment as a result of histone H4 depletion. The yeast PH05 gene contains phase nucleosomes covering promoter (UAS) sequences in the PH05 repressed state and it has been suggested that nucleosomes prevent the binding of positively acting factors to these UAS sequences. Using UKY403 we examined the length of polynucleosomes and nucleosome phasing in the PH05 upstream region by the use of micrococcal nuclease and indirect end-labeling. It was found that glucose arrest led to a severe disruption in PH05 chromatin structure and that most nucleosomes had their position altered or were lost from the PH05 promoter region. Cells undergoing nucleosome depletion synthesized large quantities of accurate PH05 transcripts even under repressive, high inorganic phosphate conditions. Histone H4 depletion did not appear to affect the repression or activation of another inducible yeast gene, CUP1. Arrest with landmarks in early G1 (in the cell division cycle mutant cdc28) or in various stages of G2 (in cdc15, cdc17 and cdc20) does not activate PH05; nor does arrest due to chromosome topology changes (in top2 or the top1top2 topoisomerase mutants). cdc14, which has its arrest landmark at a similar point in the cell cylce as cdc15, does derepress PH05. However, since it also leads to derepression of CUP1 it is probably functioning through an independent mechanism. Therefore, our data suggest that nucleosomes regulate PH05 transcription.