Alleviation of histone H1-mediated transcriptional repression and chromatin compaction by the acidic activation region in chromosomal protein HMG-14
Alleviation of histone H1-mediated transcriptional repression and chromatin compaction by the acidic activation region in chromosomal protein HMG-14
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DOI：
10.1128/mcb.17.10.5843
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发表时间：
1997-10-01
影响因子：
5.3
通讯作者：
Hansen, U
中科院分区：
文献类型：
--
作者：
Ding, HF;Bustin, M;Hansen, U
组蛋白 H1 促进浓缩、转录失活、高级染色质结构的生成。因此，必须拮抗组蛋白 H1 活性才能将染色质转化为具有转录能力的、更延伸的结构。使用猿猴病毒 40 微型染色体作为模型系统，我们现在证明，已知优先与活性染色质结合的非组蛋白染色体蛋白 HMG-14 可以完全减轻组蛋白 H1 介导的 RNA 聚合酶 II 转录抑制。 HMG-14 还会部分破坏组蛋白 H1 依赖性染色质压缩。 HMG-14 的转录增强和染色质解折叠活性是通过其酸性 C 末端区域介导的。引人注目的是，当 C 端片段被 GAL4 或 HMG-2 的酸性区域替换后，HMG-14 的转录和结构活性得以维持。这些数据支持这样的模型：HMG-14 的酸性 C 末端参与展开高级染色质结构，以促进哺乳动物基因的转录激活。
Histone H1 promotes the generation of a condensed, transcriptionally inactive, higher order chromatin structure. Consequently histone H1 activity must be antagonized in order to convert chromatin to a transcriptionally competent, more extended structure. Using simian virus 40 minichromosomes as a model system, we now demonstrate that the nonhistone chromosomal protein HMG-14, which is known to preferentially associate with active chromatin, completely alleviates histone H1-mediated inhibition of transcription by RNA polymerase II. HMG-14 also partially disrupts histone H1-dependent compaction of chromatin. Bath the transcriptional enhancement and chromatin-unfolding activities of HMG-14 are mediated through its acidic, C-terminal region. Strikingly, transcriptional and structural activities of HMG-14 are maintained upon replacement of the C-terminal fragment by acidic regions from either GAL4 or HMG-2. These data support the model that the acidic C terminus of HMG-14 is involved in unfolding higher-order chromatin structure to facilitate transcriptional activation of mammalian genes.