REGULATION OF MUSCLE GENE EXPRESSION

在肌肉发生过程中，合成的 肌瘤发育所必需的肌肉特异性蛋白质。至少在 部分这种增加反映了编码基因的转录激活。 这些蛋白质。生物学中的一个中心问题是细胞如何转录 只有它们基因组的某一部分，从而实现了分化 州政府。这项拟议研究的长期目标是确定 调控信号如何调控成肌细胞中肌肉基因的表达 差异化。 这些研究的先决条件是分离相关基因，这些基因是 在肌肉发生过程中差异表达。我们将重点关注一个家庭 编码中间丝蛋白的基因，结蛋白和 波形蛋白。结蛋白是一种肌肉特异的蛋白质，它是由 与肌肉细胞分化有关。然而，波形蛋白的合成 并不局限于肌肉，其表达并不反映 肌肉特异性调节。这两个基因的克隆提供了至少两个 确定控制基因的基本控制机制的方法 在肌肉中表达。DNA测序允许人们搜索同源基因 基因中的序列元素和周围环境中的差异 监管区域。此外，结蛋白基因的序列(5英尺 将与其他显示肌肉特异性调控的基因进行比较 它可以揭示受监管所需的常见结构元素 表情。这些假定的监管区域的功能将 通过引入正常基因和修饰基因进行测试 将真核病毒载体导入前体细胞(成肌细胞)。成肌细胞会 被刺激分化和导入基因的表达 并通过S1定位实验对宿主基因进行定量比较。 肌肉特异性基因(Desmin)应该只在分化的组织中表达 细胞。对可能的调节区中结蛋白基因的修饰 将使用缺失作图或定点突变来识别 正确调节所需的序列。这样做的长期目标是 提出的研究是为了实现对分子的理解 影响肌肉特异基因转录的机制。今年5月 涉及识别和分离符合以下条件的监管因素 与染色质相互作用，控制基因表达。

During myogenesis there is a coordinate increase in the synthesis of muscle-specific proteins essential for sarcomeric development. At least in part this increase reflects transcriptional activation of the genes coding for these proteins. A central question in biology is how cells transcribe only a certain part of their genome thereby achieving a differentiated state. The long-term objective of this proposed research is to determine how regulatory singals govern muscle gene expression during myoblast differentiation. A prerequisite for these studies is to isolate related genes which are differentially expressed during myogenesis. We shall focus on a family of genes which code for the intermediate filament proteins, desmin and vimentin. Desmin is a muscle-specific protein which is synthesized concommitant with muscle cell differentiation. However, vimentin synthesis is not restricted to muscle and its expression does not reflect muscle-specific regulation. Clones of these two genes provide at least two approaches for determining fundamental control mechanisms governing gene expression in muscle. DNA sequencing allows one to search for homologous sequence elements within the genes and differences within the surrounding regulatory regions. In addition, the sequence of the desmin gene (5 feet end) will be compared to other genes exhibiting muscle-specific regulation which may reveal common structural elements required for regulated expression. The functionality of these presumptive regulatory regions will be tested by the introduction of both normal and modified genes via eukaryotic viral vectors into precursor cells (myoblasts). Myoblasts will be stimulated to differentiate and the expression of the introduced genes and host genes will be quantitated and comapred by S1 mapping experiments. Muscle-specific genes (desmin) should be expressed only in differentiated cells. Modification of the desmin gene in putative regulatory regions by deletion mapping or site-specific mutagenesis will be employed to identify sequences required for correct regulation. The long range goal of this proposed research is to achieve an understanding of the molecular mechanisms affecting transcription of a muscle-specific gene. This may involve the identification, and isolation of regulatory factors which interact with chromatin and control gene expression.