MECHANISMS OF YEAST TRANSCRIPTIONAL REGULATORS

这项工作的长期目标是用精确的分子术语来理解 ， 酵母转录抑制因子α2是如何关闭转录的 两套细胞类型特异性基因。这种蛋白质总是结合在一起发挥作用 N 另外两种蛋白质中的一种。在阿尔法细胞中，它与 GRm蛋白；在a/α细胞中，它与al蛋白起作用。这些访问器 蛋白质将α2定向到两种不同类型的操作者，从而启用 Alpha 2关闭两组不同基因的表达。三个指定 C 该提案涉及的问题如下：(1)如何实现这些 调控蛋白共同作用？(2)它们如何重新洗牌以创造 不同的监管活动？(3)一旦与运营商捆绑在一起，如何 Alpha 2对其目标基因进行抑制。 基本的方法是利用简单的生化和遗传结果 构建和测试分子模型的实验。一次即刻 例如，实验目标是重建和研究 仅使用纯化蛋白的不同的调节剂配对组合。 第二种实验方法是重建转录 α2在体外的抑制作用及其步长的测定 被阿尔法2的作用所阻止的转录。 拟议中的阿尔法2研究应该提供一个详细的分子图景。 展示了在一个简单的真核生物S。 酿酒。考虑到阿尔法2与细胞类型调节器在 高等生物体，很可能许多原理是为 阿尔法2将适用于其他设置。对分子的基本认识 R 作为细胞专业化基础的事件对于了解 进程可能会失败，这种情况可能会导致许多不同的 病态。

The long-term goal of this work is to understand, in precise molecular term , how the yeast transcriptional repressor alpha 2 turns off transcription of two set of cell-type specific genes. This protein always acts in combinati n with one of two additional proteins. In alpha cells it cooperates with the GRM protein; in a/alpha cells, it acts with the al protein. These accessor proteins director alpha 2 to two different types of operator and thus enabl alpha 2 to turn off expression of two different sets of genes. Three specif c questions addressed by the proposal are as follows: (1) How do these regulatory proteins act together? (2) How do they reshuffle to create different regulatory activities? (3) How, once bound to its operators, doe alpha 2 carry out repression of its target genes. The basic approach is to use results of simple biochemical and genetic experiments to construct and test molecular models. ONe immediate experimental goal, for example, is a reconstruction and study of the different pairwise combinations of regulators using only purified proteins. A second experimental approach is a reconstruction of transcriptional repression by alpha 2 in vitro and a determination of the step in transcription that is blocked by the action of alpha 2. The proposed studies of alpha 2 should provide a detailed molecular picture showing how cell specialization is maintained in a simple eukaryote, S. cerevisiae. Given the similarity of alpha 2 to cell-type regulators in higher organisms, it is likely that many of the principles developed for alpha 2 will apply in other settings. A basic understanding of the molecul r events underlying cell specialization is essential for understanding how th process can fail, a condition that can give rise to a number of different pathological states.