Reg of SM22 Alpha Transcription in Smooth Muscle Cells

描述(申请人摘要)：血管平滑肌的能力 细胞(SMC)调节其对动脉损伤的反应已被牵连 在血管增生性综合征的发病机制中包括 冠状动脉介入治疗后动脉粥样硬化和再狭窄。我们有 以SMC特异性小鼠SM22a启动子为模型系统 控制VSMC发育和分化的转录程序。 在本奖项的最初供资周期内，顺位代理要素和 控制SM22a启动子表达的反式作用因子是 已定义。SM22a启动子上的两个核蛋白结合位点(SME-1和 SME-4)被识别为包含结合了 特异性结合MADS盒转录因子SRF。值得注意的是，一个 SME-L或SME-4的多语种副本是必要且充分的 在转基因小鼠中限制LacZ报告基因对动脉SMCs的活性。 这些数据让我们假设，SRF与其他潜在的 新的转录激活因子(和潜在的抑制因子)，调节 SMC特异性基因表达和SMC表型。该计划的总体目标 建议的研究是为了阐明SRF依赖的分子基础 动脉系膜细胞转录。这些研究的具体目的是：i) 检测SMC中SRF-Carg盒活性的分子基础，II)检测 调节SM22a启动子活性的蛋白质-蛋白质相互作用 SMC，特别关注SRF/Homeobox蛋白相互作用，III) 检测LIMK-1介导的SM22cz激活的信号通路 启动子，以及iv)检测SRF-/-ES细胞对 SMC系(S)在SRF-/-C57BL/6嵌合体小鼠中的表达及其下游SMC和 胚胎中受SRF调控的中胚层基因。总而言之，这些研究 将阐明转录程序和一个重要的信号通路 这调节SM22a基因在SMC中的表达。因为卡格 已在多个其他特定于SMC的产品中确定了包含框的元素 这些研究将提供对分子的基本见解。 SMC分化的调控机制及血管SMC的调控 表型。

DESCRIPTION (Applicant's abstract): The capacity of vascular smooth muscle cells (SMCs) to modulate their response to arterial injury has been implicated in the pathogenesis of vascular proliferative syndromes including atherosclerosis and restenosis following coronary intervention. We have utilized the SMC-specific mouse SM22a promoter as a model system to elucidate the transcriptional programs that control VSMC development and differentiation. During the initial funding cycle of this award, the cis-acting elements and trans-acting factors that control expression of the SM22a promoter were defined. Two nuclear protein binding sites in the SM22a promoter (SME- 1 and SME-4) were identified which contain consensus CArU boxes that bind specifically to the MADS box transcription factor, SRF. Remarkably, a multimerized copy of either SME-l or SME-4 is necessary and sufficient to restrict activity of a LacZ reporter gene to arterial SMCs in transgenic mice. These data lead us to hypothesize that SRF, in concert with other potentially novel transcriptional activators (and potentially repressors), regulates SMC-specific gene expression and SMC phenotype. The overall goal of the proposed studies is to elucidate the molecular basis of SRF-dependent transcription in arterial SMCs. The specific aims of these studies are to: i) Examine the molecular basis of SRF-CArG box activity in SMCs, ii) Examine protein-protein associations that modulate activity of the SM22a promoter in SMCs with particular attention on SRF/homeobox protein interactions, iii) Examine signaling pathways underlying LIMK- 1-mediated activation of the SM22cz promoter, and iv) Examine the capacity of SRF-/- ES cells to contribute to the SMC lineage(s) in SRF-/- -C57BL/6 chimenc mice and define downstream SMC and mesodermal genes regulated by SRF in the embryo. Taken together, these studies will elucidate the transcriptional program and an important signaling pathway that modulates expression of the SM22a gene in SMCs. Because CArG box-containing elements have been identified in multiple other SMC-specific genes these studies will provide fundamental insights into the molecular mechanisms that control SMC differentiation and the modulation of vascular SMC phenotype.