Stimulation of Transcription Accompanying Relaxation of Chromatin Structure in Cells Overexpressing High Mobility Group 1 Protein (*)
Stimulation of Transcription Accompanying Relaxation of Chromatin Structure in Cells Overexpressing High Mobility Group 1 Protein (*)
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过度表达高迁移率组 1 蛋白的细胞中转录的刺激伴随着染色质结构的松弛 (*)
DOI：
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发表时间：
1995
影响因子：
4.8
通讯作者：
Michiteru Yoshida
中科院分区：
文献类型：
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作者：
Yoshimasa Ogawa;S. Aizawa;H. Shirakawa;Michiteru Yoshida
我们开发了小鼠C-127细胞系，静态过表达高迁移率族（HMG）蛋白1和2，通过将它们与携带各自cDNA序列的牛乳头状瘤病毒质粒一起转染。使用这些细胞系，我们研究了这些HMG蛋白对伴随转录的染色质结构的调节的影响。与对照细胞相比，过表达HMG 1蛋白的细胞中的HMG 1 mRNA和蛋白水平分别增强约7倍和3倍，而过表达HMG 2蛋白的细胞中的HMG 1 mRNA和蛋白水平分别增强约17倍和9倍。与对照细胞相比，转染到细胞中的报告基因的表达在过表达HMG 1的细胞中增强约2倍，但不表达HMG 2，与基因和启动子的来源无关。在过表达HMG 1蛋白的细胞中，来自报告质粒的微型染色体比过表达HMG 2蛋白的细胞和对照细胞更容易被微球菌核酸酶消化。微球菌核酸酶的可及性增强并不局限于表达基因和启动子，而是涉及整个微染色体，这表明基因表达的增强是由于HMG 1蛋白对整个微染色体区域的缩合变化所致。过表达HMG的细胞中的微型染色体含有增强量的相应HMG蛋白，同时减少量的组蛋白H1。这些结果表明，HMG 1和− 2蛋白在调节染色质结构方面具有不同的功能，HMG 1蛋白可能维持各自基因的结构，以确保其作为模板的活性得到充分表达。在过表达HMG蛋白的细胞中伴随基因转录的染色质结构的调节的这些观察可能提供关于这些蛋白质的功能的重要信息。
We developed murine C-127 cell lines that stationarily overexpress high mobility group (HMG) proteins 1 and 2 by transfecting them with the bovine papilloma virus plasmid carrying their respective cDNA sequences. Using these cell lines, we examined the effects of these HMG proteins on the modulation of chromatin structure that accompanied transcription. The levels of HMG1 mRNA and protein in cells overexpressing HMG1 protein were enhanced about 7- and 3-fold, respectively, in comparison with control cells, whereas those in cells overexpressing HMG2 protein were enhanced about 17- and 9-fold. The expression of reporter genes transfected into the cells was enhanced approximately 2-fold in cells overexpressing HMG1, but not HMG2, in comparison with those in control cells, irrespective of the sources of the genes and promoters. The minichromosome derived from the reporter plasmid in cells overexpressing HMG1 protein was more susceptible to micrococcal nuclease digestion than those in cells overexpressing HMG2 protein and control cells. The enhanced accessibility to micrococcal nuclease was not restricted to the expressing gene and promoter but involved the entire minichromosome, suggesting that the enhancement of gene expression resulted from changes in the condensation of the entire minichromosomal region by HMG1 protein. Minichromosomes in cells overexpressing HMG contained enhanced amounts of the respective HMG proteins and simultaneously reduced amounts of histone H1s. These results suggest that HMG1 and −2 proteins have different functions in the modulation of chromatin structure, and that HMG1 protein may sustain the structure of the respective gene to ensure that its activity as a template is expressed fully. These observations on the modulation of chromatin structure accompanying gene transcription in cells overexpressing HMG protein may provide important information on the function of these proteins.
DOI：
10.1073/pnas.84.21.7413
发表时间：
1987-11-01
影响因子：
11.1
作者：
FELGNER, PL;GADEK, TR;DANIELSEN, M
通讯作者：
DANIELSEN, M