TRANSCRIPTIONAL ACTIVATION BY RAP AND GCR IN YEAST

大量基因(主要是糖酵解基因)的表达 或翻译成分基因)，影响植物的生长速度。 发芽酵母酿酒酵母依次受 只有为数不多的几种调节蛋白的作用。在1990年的一份出版物中，我 实验室提供的证据表明，其中两种调控蛋白，RAP 和GCR，相互依赖地激活转录。随后，其他人 预言了一类新的调节分子的存在， 被称为共激活剂，其假定的作用不是结合DNA，而是 联系DNA结合的激活剂和转录机制。 我们认为GCR可能是共激活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)；GCR依赖的激活 ADH1启动子仅通过ADH1 UASRPG和N-末端发生 潜在的激活结构域位于两个独立的 GCR的基本部分。推测的GCR激活结构域是一个 Gcn4和Gcn4中类似于强激活结构域的两亲性α-螺旋 VP16，特别是关于大体积疏水的放置 已知对VP16激活很重要的残基。这个 这里提出的实验测试了GCR共激活剂模型和两个 GCR/RAP相互依赖的竞争模式。的具体目标 这一建议是为了：(1)进一步刻画本质N-末端 和GCR内的C-末端结构域；(2)尝试建立 这些领域的结构/功能关系；(3)寻找 GCR+和GCR-产生的RAP分子的性质差异 细胞；以及(4)检测RAP与GCR或AN之间的关联 中间因素。这项研究的成功完成将 有助于我们理解GCR的功能，以及GCR的复杂作用 RAP以及这些角色在体内是如何平衡的，以及通过什么方式 酵母细胞的生长速度是受控制的。了解的功能 酵母中的RAP和GCR可以同时为我们的知识做出贡献 哺乳动物细胞如何控制它们的生长速度。最后，如果 GCR协同激活剂模型是正确的，需要学习的东西很多 这项关于真核转录起始机制的工作。 因此，这项研究最终可能提供以下信息 对于理解宇宙中的复杂现象至关重要 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.