ROLE FOR TRANSCRIPTION FACTOR LSF IN MAMMALIAN CELLS

基因表达的精确程序控制着许多复杂的生物学过程， 过程，包括细胞生长、分化和发育。 一个 阐明正常控制被破坏的机制， 如发生在各种肿瘤和一些出生的发展过程中， 缺陷，因此需要对监管的基本理解， 基因表达。 启动所需的转录机制 RNA聚合酶II启动子的转录是相当复杂的，包括 特异性DNA结合蛋白，其仅控制转录， 含有其识别序列的启动子。 SV 40晚期启动子的表达在细胞周期中受到精细调控。 用SV 40裂解感染细胞。 细胞转录因子LSF， 其刺激从主要晚期SV 40起始位点的转录， 结合两个不同的启动子元件，其中心在45和265 bp上游， 这个晚期起始位点 这些研究的主要目标是确定 LSF在SV 40裂解过程中的转录调节作用 在哺乳动物细胞内。 具体目标是解决 这个广泛的目标是：（1）克隆LSF的基因，并定义两个 蛋白质的DNA结合和转录激活区;（2） 详细研究了LSF在两个识别阶段的蛋白质-DNA相互作用 位点，并确定是否弯曲的DNA和/或不同的 LSF的构象在差异识别中起作用;（3） 确定SV 40内两个LSF结合位点的功能 启动子;（4）确定LSF刺激的机制 转录;（5）研究LSF和 在相邻或重叠序列处结合的转录因子，和（6） 以确定LSF活性是否受SV 40感染调节。 LSF（一种细胞蛋白）也可能在调节 细胞基因的表达。 LSF特异性结合邻近的序列 c-fos启动子中的血清反应元件。 此外，多个 细胞周期调节的人胸苷酸合酶内的序列， 胸苷激酶启动子与LSF识别位点高度同源。 LSF的细胞功能将通过描述LSF结合来解决 细胞启动子内的位点，决定LSF是否激活或 抑制这些启动子的转录，决定LSF 活性受血清、确定的生长因子或在细胞生长过程中调节。 周期 这些研究将有助于确定LSF是否调节基因表达 对特定的细胞外信号作出反应。

Precise programs of gene expression control many complex biological processes, including cell growth, differentiation, and development. An elucidating of the mechanisms by which the normal controls are subverted, as occurs in various neoplasms and during the development of some birth defects, will therefore require a basic understanding of the regulation of gene expression. The transcription machinery required for the initiation of transcription at RNA polymerase II promoters is quite complex, including specific DNA-binding proteins, which control transcription only at promoters containing their recognition sequences. Expression from the SV40 late promoter is exquisitely regulated during lytic infection of cells with SV40. The cellular transcription factor LSF, which stimulates transcription from the major late SV40 initiation site, binds two distinct promote elements centered at 45 and 265 bp upstream of this late initiation site. The broad goal of these studies is to define the role of LSF in regulation of transcription both during the SV40 lytic cycle and within the mammalian cell. The specific aims that will address this broad goal are: (1) to clone the gene for LSF, and define both the DNA-binding and transcriptional activation regions of the protein; (2) to study in detail the protein-DNA interactions of LSF at its two recognition sites, and to determine whether bending of DNA and/or different conformations of LSF play a role in the differential recognition; (3) to determine the function of the two LSF binding sites within the SV40 promoters; (4) to determine the mechanism by which LSF stimulates transcription; (5) to investigate potential interactions between LSF and transcription factors binding at adjacent or overlapping sequences, and (6) to determine whether LSF activity is regulated by SV40 infection. LSF (a cellular protein) is likely to also play a role in regulating expression of cellular genes. LSF specifically binds sequences adjacent to the serum response element in the c-fos promoter. In addition, multiple sequences within the cell cycle-regulated human thymidylate synthase and thymidine kinase promoters are highly homologous to LSF recognition sites. The cellular function of LSF will be addressed by delineating LSF binding sites within cellular promoters, determining whether LSF activates or represses transcription of these promoters, determining whether LSF activity is regulated by serum, defined growth factors, or during the cell cycle. These studies will help determine if LSF regulates gene expression in response to specific extracellular signals.