Activation of utrophin promoter by heregulin via the ets-related transcription factor complex GA-binding protein α/β
Activation of utrophin promoter by heregulin via the ets-related transcription factor complex GA-binding protein α/β
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DOI：
10.1091/mbc.10.6.2075
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发表时间：
1999-06-01
影响因子：
3.3
通讯作者：
Gammeltoft, S
中科院分区：
文献类型：
--
作者：
Khurana, TS;Rosmarin, AG;Gammeltoft, S
肌营养不良蛋白/肌营养不良蛋白相关蛋白是染色体X编码的肌营养不良蛋白的常染色体同源物。在成人骨骼肌中，肌营养蛋白在神经肌肉接头处高度富集。然而，utrophin基因表达调控的分子机制尚未确定。在这里，我们证明了生长因子heregulin增加从头肌细胞培养中的utrophin转录。使用utrophin启动子的突变体报告构建体，我们将启动子的N-box区域定义为调蛋白介导的活化的关键。使用这个区域的utrophin启动子的DNA亲和纯化，免疫印迹，在体外激酶测定，电泳迁移率变动测定，并在体外培养的肌肉细胞中的表达，我们证明，ets相关的GA结合蛋白α/β转录因子的utrophin启动子的激活剂。两者合计，这些结果表明，GA结合蛋白α/β复合物的转录因子结合和激活肌营养蛋白启动子在肌肉细胞培养物中的调蛋白激活的细胞外信号调节激酶的响应。这些研究结果表明，在杜氏肌营养不良症中实现utrophin上调的方法，以及神经突衍生的生长因子如调蛋白可能影响utrophin基因表达的调节和随后在骨骼肌神经肌肉接头处富集的机制。
Utrophin/dystrophin-related protein is the autosomal homologue of the chromosome X-encoded dystrophin protein. In adult skeletal muscle, utrophin is highly enriched at the neuromuscular junction. However, the molecular mechanisms underlying regulation of utrophin gene expression are yet to be defined. Here we demonstrate that the growth factor heregulin increases de novo utrophin transcription in muscle cell cultures. Using mutant reporter constructs of the utrophin promoter, we define the N-box region of the promoter as critical for heregulin-mediated activation. Using this region of the utrophin promoter for DNA affinity purification, immunoblots, in vitro kinase assays, electrophoretic mobility shift assays, and in vitro expression in cultured muscle cells, we demonstrate that ets-related GA-binding protein alpha/beta transcription factors are activators of the utrophin promoter. Taken together, these results suggest that the GA-binding protein alpha/beta complex of transcription factors binds and activates the utrophin promoter in response to heregulin-activated extracellular signal-regulated kinase in muscle cell cultures. These findings suggest methods for achieving utrophin up-regulation in Duchenne's muscular dystrophy as well as mechanisms by which neurite-derived growth factors such as heregulin may influence the regulation of utrophin gene expression and subsequent enrichment at the neuromuscular junction of skeletal muscle.