The DNA-binding properties of two heat shock factors, HSF1 and HSF3, are induced in the avian erythroblast cell line HD6
The DNA-binding properties of two heat shock factors, HSF1 and HSF3, are induced in the avian erythroblast cell line HD6
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DOI：
10.1128/mcb.15.10.5268
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发表时间：
1995-10
影响因子：
5.3
通讯作者：
Akira Nakai;Yoshinori Kawazoe;M. Tanabe;Kazuhiro Nagata;R I Morimoto
中科院分区：
文献类型：
--
作者：
Akira Nakai;Yoshinori Kawazoe;M. Tanabe;Kazuhiro Nagata;R I Morimoto
鸟类细胞表达三种热休克转录因子 (HSF) 基因，对应于一种新因子 HSF3，以及小鼠和人类 HSF1 和 HSF2 的同源物。对这些 HSF 的生化和细胞生物学特性的分析表明，HSF3 具有与 HSF1 和 HSF2 共同的特性，但又具有与两者不同的特征。 HSF3 在成红细胞系 HD6、淋巴母细胞系 MSB 和胚胎成纤维细胞中组成型表达，但其 DNA 结合活性仅在 HD6 细胞暴露于热休克时才被诱导。 HD6细胞中HSF3 DNA结合活性的获得伴随着从非DNA结合二聚体到DNA结合三聚体的寡聚化，而热休克对HSF1的影响是惰性单体到DNA结合三聚体的寡聚化。与 HSF1 相比，HSF3 DNA 结合活性的诱导被延迟。与 HSF1 一样，热休克导致 HSF3 易位至细胞核。 HSF 表现出转录激活剂的特性，通过使用含有热激元件的报告构建体测量的瞬时过表达的 HSF3 的刺激活性来判断，并通过 GAL4 报告构建体上的嵌合 GAL4-HSF3 蛋白的活性独立测定。这些结果表明，HSF3 在禽类细胞中受到负调控，并在热激后在某些细胞中获得 DNA 结合活性。
Avian cells express three heat shock transcription factor (HSF) genes corresponding to a novel factor, HSF3, and homologs of mouse and human HSF1 and HSF2. Analysis of the biochemical and cell biological properties of these HSFs reveals that HSF3 has properties in common with both HSF1 and HSF2 and yet has features which are distinct from both. HSF3 is constitutively expressed in the erythroblast cell line HD6, the lymphoblast cell line MSB, and embryo fibroblasts, and yet its DNA-binding activity is induced only upon exposure of HD6 cells to heat shock. Acquisition of HSF3 DNA-binding activity in HD6 cells is accompanied by oligomerization from a non-DNA-binding dimer to a DNA-binding trimer, whereas the effect of heat shock on HSF1 is oligomerization of an inert monomer to a DNA-binding trimer. Induction of HSF3 DNA-binding activity is delayed compared with that of HSF1. As occurs for HSF1, heat shock leads to the translocation of HSF3 to the nucleus. HSF exhibits the properties of a transcriptional activator, as judged from the stimulatory activity of transiently overexpressed HSF3 measured by using a heat shock element-containing reporter construct and as independently assayed by the activity of a chimeric GAL4-HSF3 protein on a GAL4 reporter construct. These results reveal that HSF3 is negatively regulated in avian cells and acquires DNA-binding activity in certain cells upon heat shock.