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Expression of the HSPB2 and αB-crystallin genes located in a head-to-head manner

HSPB2 和 αB-晶状体蛋白基因的表达以头对头的方式定位

基本信息

批准号：
10680654
负责人：
IWAKI Akiko
金额：
$ 1.92万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10680654/
关键词：
Heat shock protein Crystallin Stress ストレス蛋白質クリスタン

项目摘要

Previously we identified a new member of the α-crystallin/small heat shock protein (HSP) family and named it HSPB2 (Genomics, 1997). The HSPB2 gene and the αB-crystallin gene, another member of the small HSP family, are arranged in a head-to-head manner with an intergenic sequence of 956 bp, raising a possibility of shared enhancer elements for their expression. In this study we examined spatial and temporal expression patterns of the newly identified HSPB2 gene and compared with that of the αB-crystallin gene. Furthermore, we investigated the regulatory mechanisms of expression of the two genes in cultured cells and transgenic mice. (1) Northern blotting and in situ hybridization revealed that the HSPB2 gene is expressed in heart and muscles but not in eye lens. Although the level of HSPB2 mRNA was much lower than that of αB-crystallin, the developmental profiles of their expression were similar in muscles (in preparation). (2) Functional promoter analysis of the two genes in C2C12 cells and transgenic mice revealed a competition of muscle specific enhancer elements, which arc present in the intergenic region (in preparation). (3) αB-Crystallin, but not HSPB2, accumulates in glial cells in response to high extracellular potassium concentrations. Functional promoter analysis using deletion and mutation constructs revealed that the heat shock element (HSE) is essential for transcriptional activation of the αB-crystallin gene by KCl in U-251MG.Gel mobility shift and antibody supershift assays showed that KCl induces the HSE-binding activity of heat shock factor 2 (HSF2), suggesting that HSF2 is involved in KCl-depedent increases in αB-crystallin mRNA in glial cells (submitted).

此前，我们鉴定了α-晶状体蛋白/小热休克蛋白（HSP）家族的一个新成员，并将其命名为HSPB2（Genomics，1997）。 HSPB2基因和αB-晶状体蛋白基因（小HSP家族的另一个成员）以头对头的方式排列，具有956 bp的基因间序列，这提高了它们表达共享增强子元件的可能性。在这项研究中，我们检查了新鉴定的 HSPB2 基因的空间和时间表达模式，并与 αB-晶状体蛋白基因进行了比较。此外，我们研究了这两个基因在培养细胞和转基因小鼠中表达的调控机制。 (1)Northern印迹和原位杂交显示HSPB2基因在心脏和肌肉中表达，但在眼晶状体中不表达。尽管 HSPB2 mRNA 的水平远低于 αB-晶状体蛋白，但它们在肌肉（准备中）中的表达发育谱相似。 (2) C2C12细胞和转基因小鼠中两个基因的功能启动子分析揭示了肌肉特异性增强子元件的竞争，这些增强子元件存在于基因间区域（准备中）。 (3) αB-晶状体蛋白（而非 HSPB2）响应高细胞外钾浓度而在神经胶质细胞中积聚。使用缺失和突变构建体的功能启动子分析表明，热休克元件 (HSE) 对于 U-251MG 中 KCl 转录激活 αB-晶状体蛋白基因至关重要。凝胶迁移率变动和抗体超移测定表明，KCl 诱导热休克因子 2 (HSF2) 的 HSE 结合活性，表明 HSF2 参与 KCl 依赖性增加胶质细胞中的 αB-晶状体蛋白 mRNA（已提交）。