TRANSCRIPTIONAL ACTIVATION BY RAP AND GCR IN YEAST

大量基因（主要是糖酵解基因）的表达 或翻译组分基因），其影响细胞的生长速率。 芽殖酵母酿酒酵母的影响，反过来， 只有少数调节蛋白的作用。 在1990年的一份出版物中， 实验室提出的证据表明，这些调节蛋白中的两种，RAP 和GCR相互依赖地激活转录。 随后，其他 预测了一类新的调节分子的存在， 称为辅激活因子，其假定的作用不是结合DNA，而是 与DNA结合的激活剂和转录机器接触。 我们认为GCR可能是一种共活化剂的想法得到了以下支持 数据：GCR是单个激活的绝对要求， 分离的RAP结合位点（UASPRPG元件）; ADH 1启动子仅通过ADH 1 UASRPG和N-末端 潜在的激活域位于两个独立的 大中华区的重要组成部分。假定的GCR激活结构域是一个 两亲性α-螺旋类似于GCN 4中的强激活结构域， VP 16，特别是关于大体积疏水性 已知对VP 16的激活重要的残基。的 这里提出的实验测试GCR共激活模型和两个 GCR/RAP相互依存的竞争模式。 的具体目标 该建议是：（1）进一步表征必需的N-末端 GCR内的C-末端结构域;（2）尝试建立 这些结构域的结构/功能关系;（3）寻找 GCR+和gcr-中产生的RAP分子之间的定性差异 细胞;和（4）测试RAP和GCR之间的关联或 中间因子 这项研究的成功完成将 有助于我们理解GCR功能， RAP以及这些作用如何在体内平衡，以及 在酵母细胞中控制生长速率。 了解的功能 酵母中的RAP和GCR可以同时有助于我们的知识 哺乳动物细胞是如何控制生长速度的 最后，如果 GCR共激活因子模型是正确的，值得借鉴 本工作是关于真核生物转录起始机制的研究。 因此，这项研究可能最终提供的信息是， 对于理解复杂的自然现象 发育、癌症和衰老。

The expression of a very large number of genes (mostly glycolytic genes or translational component genes) that influence the growth rate of the budding yeast Saccharomyces cerevisiae is influenced in turn by the action of only a few regulatory proteins. In a 1990 publication my laboratory presented evidence that two of these regulatory proteins, RAP and GCR, activate transcription interdependently. Subsequently, others have predicted the existence of a new class of regulaory molecules, called coactivators, whose postulated role is not to bind DNA but to contact both the DNA-bound activator and the transcriptional machinery. Our idea that GCR may be a coactivator is supported by the following data: GCR is an absolute requirement for activation by a single, isolated RAP binding site (UASPRPG element); GCR-dependent activation in the ADH1 promoter occurs only through the ADH1 UASRPG and an N-terminal potential activation domain is located within one of two separate essential segments of GCR. The putative GCR activation domain is an amphipathic Alpha-helix similar to strong activation domains in GCN4 and VP16, especially with respect to the placement of bulky hydrophobic residues that are known to be important for activation by VP16. The experiments proposed here test the GCR coactivator model and two competing models for GCR/RAP interdependence. The specific goals of this proposal are to: (1) further characterize the essential N-terminal and C-terminal domains within GCR; (2) try to establish the structure/function relationships of those domains; (3) look for qualitative differences between RAP molecules produced in GCR+ and gcr- cells; and (4) test for association between RAP and GCR or an intermediate factor. The successful completion of this research will contribute to our understanding of GCR function, the complex roles of RAP and how those roles are balanced in vivo, and the means by which growth rate is controlled in yeast cells. Understanding the function of RAP and GCR in yeast could simultaneously contribute to our knowledge about how mammalian cells control their growth rate. Finally, if the GCR coactivator model is correct, a great deal should be learned from this work about the mechanism of eucaryotic transcription initiation. This research might therefore ultimately provide information which is of the utmost importance for understanding the complex phenomena of development, cancer, and aging.