NUCLEAR MATRIX MEDIATED TRANSCRIPTIONAL CONTROL OF OSTEOBLAST GENE EXPRESSION

我们将讨论的假设，即核基质有助于 细胞生长和骨特异性基因表达的转录调控 在成骨细胞表型的进行性发育过程中， 核基质在骨细胞中受到发育调节。 我们 实验策略最初是表征核基质 与启动子显示序列特异性相互作用的蛋白质 调控序列：1）细胞周期调控组蛋白基因 仅在增殖的成骨细胞中表达;和2）骨钙素基因 在成熟成骨细胞增殖后表达， 细胞外基质矿化 这些受调控的表达 核基质蛋白将被检查与成骨细胞 分化和潜在的分子机制与 核基质介导的发育转录控制。 我们将 研究核基质对以下物质的发育反应性： TGF β、1，25（OH）2D 3和地塞米松。 我们的“工作模型”是核基质支持成骨细胞 通过促进基因定位， 以及反式激活因子的浓度和定位。 核结构的这些特征， 基于染色质结构和核小体的基因组性质 组织可以影响相关基因的转录控制， 随着细胞生长和增殖后成熟分化， 成骨细胞 在完整的成骨细胞中， 在多个独立的顺式作用元件上的调节活性， 从而有助于转录的正调控和负调控 由一系列生理介质所控制， 和类固醇激素反应。 实验解决这一假设是一致的中心 该计划项目的主题，细胞结构的参与， 调节细胞的进行性发育表达并受其调节 生长和骨细胞相关基因。

We will address the hypothesis that the nuclear matrix contributes to transcriptional control of cell growth and bone-specific gene expression during progressive development of the osteoblast phenotype and that the nuclear matrix is regulated developmentally in bone cells. Our experimental strategy is initially to characterize the nuclear matrix proteins that exhibit sequence-specific interactions with promoter regulatory sequences of: 1) the cell cycle regulated histone genes expressed only in proliferating osteoblasts; and 2) the osteocalcin gene expressed post-proliferatively in mature osteoblasts undergoing extracellular matrix mineralization. The regulated expression of these nuclear matrix proteins will then be examined in relation to osteoblast differentiation and potential molecular mechanisms associated with nuclear matrix-mediated developmental transcriptional control. We will investigate the developmental responsiveness of the nuclear matrix to TGFBeta, 1,25(OH)2D3 and dexamethasone. Our "working model" is that the nuclear matrix supports osteoblasts proliferation and differentiation by facilitating gene localization as well as the concentration and localization of transactivation factors. These features of nuclear architecture, together with structural properties of the genome, based on chromatin structure and nucleosome organization can influence transcriptional control of genes associated with cell growth and with the post-proliferative, mature differentiating osteoblast. In intact osteoblasts may support the integration of regulatory activities at multiple, independent cis-acting elements, thereby contributing to positive and negative control of transcription by a broad spectrum of physiological mediators that are developmentally and steroid hormone responsive. Experimentally addressing this hypothesis is consistent with the central theme of the Program Project, the involvement of cell structure as its regulates and is regulated by progressive development expression of cell growth and bone cell-related genes.