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Smooth muscle-specific transcriptional regulation by SRF and homeodomain proteins

SRF 和同源域蛋白的平滑肌特异性转录调节

基本信息

批准号：
11838010
负责人：
NISHIDA Wataru
金额：
$ 1.41万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11838010/
关键词：
Vascular smooth muscle Phenotypic modulation Signal transduction Transcriptional regulation Serum Response Factor Homeodomain proteins GATA transcription factors Serum response factor serum response factor

项目摘要

While serum response factor (SRF)/CArG box interaction has been well documented for a variety of transcription systems, including immediate early and muscle genes, it cannot solely be responsible for transcription in respective tissues. Here, we identified two cis-elements in the alphal-integrin promoter region in addition to CArG box : a TAAT sequence, a consensus-binding site for homeoproteins, and a GATA family-binding box. We further cloned a homeobox cDNA, Nkx-3.2, which is mainly expressed in smooth muscle tissues and skeletal structures. Gel-shift assays showed a ternary complex formation of SRF and Nkx-3.2 or GATA-6 with their corresponding cis-elements. Further, Nkx-3.2, SRF, and GATA-6 or their respective functional domains transactivate synergistically the alphal-integrin gene in vascular SMC-derived cell line and heterologous cells. We conclude that transcription of alphal-integrin in vascular SMCs is regulated by coordinated interactions between Nkx-3.2, SRF, GATA-6 and their corresponding cis-elements. In addition, we characterized the transcriptional machinery of the beta-TM gene in SMCs. Promoter and gel mobility shift analyses revealed an obligatory role for serum response factor (SRF) and its interaction with the CArG box sequence in the SMC-specific transcription of the beta-TM gene in differentiated SMCs. We further isolated a novel homologue of the Barx homeoprotein family, Barx1b, from chicken gizzard. Barx1b was exclusively localized to SMCs of the upper digestive organs and their attached arteries and to craniofacial structures. SRF and Barx1b bound each other directly, coordinately transactivated the beta-TM gene in differentiated SMCs and heterologous cells, and formed a temary complex with a CArG probe. Taken together, these results suggest that SRF, homeodomain proteins, and/or GATA family transcription factors are coordinately involved in the tissue-specific transcription of the smooth muscle genes.

虽然血清反应因子（SRF）/CArG盒相互作用已被充分记录用于各种转录系统，包括立即早期和肌肉基因，但它不能单独负责相应组织中的转录。在这里，我们确定了两个顺式元件的整合素启动子区域除了CArG盒：TAAT序列，同源异型蛋白的共识结合位点，和一个加塔家族结合框。我们进一步克隆了一个同源异型盒cDNA，Nkx-3.2，它主要在平滑肌组织和骨骼结构中表达。凝胶位移分析显示SRF和Nkx-3.2或加塔-6与它们相应的顺式元件形成三元复合物。此外，Nkx-3.2、SRF和加塔-6或它们各自的功能结构域协同反式激活血管SMC衍生的细胞系和异源细胞中的细胞α 1-整联蛋白基因。我们的结论是，血管平滑肌细胞中的Nkx-3.2，SRF，加塔-6和它们相应的顺式元件之间的协调相互作用的转录调节β-整合素。此外，我们的特点是在SMC中的β-TM基因的转录机制。启动子和凝胶迁移率变化分析揭示了血清反应因子（SRF）的强制性作用，其与CArG盒序列在分化的SMC中的β-TM基因的SMC特异性转录。我们进一步分离了一个新的同源的Barx同源蛋白家族，Barx 1b，从鸡砂囊。Barx 1b仅定位于上消化器官及其附属动脉的SMC和颅面结构。SRF与Barx 1b直接结合，协同反式激活分化SMC和异源细胞中的β-TM基因，并与CArG探针形成三元复合物。两者合计，这些结果表明，SRF，同源结构域蛋白，和/或加塔家族转录因子协调参与平滑肌基因的组织特异性转录。