MOLECULAR MECHANISM OF GENETIC RECOMBINATION IN YEAST

这项研究项目的长期目标是了解 酵母遗传重组的分子机制。在实验中 在这份提案中，我们将分离和鉴定酵母DNA 作为启动重组的首选位点的序列 事件。此外，我们还将研究酵母的重组 转座元件以及这些序列与一个 重组抑制因子。 基因重组事件并不均匀地沿 染色体；相反，存在特定的位置(热点)，它们充当 基因交流的局部刺激物。我们的目标是分离酵母菌 重组热点并研究它们的作用机制。我们有 已经证明核糖体RNA基因簇中存在DNA序列 包含一个重组热点。这些实验的具体目的 在这项建议中提出：(1)研究 核糖体DNA中存在的热点，(2)分离额外的序列 它们充当重组热点，以及(3)分离基因突变。 其产物在热点处引发重组事件的基因。 酵母Ty(转座子酵母)元件可以从酵母基因组中去除 通过末端重复的Delta序列之间的重组 他们的目的。SPM2基因产物抑制至少一个基因的切除 转座子，被称为Ty912。为了考察其作用机制， SPM2基因产物，我们将确定其对Ty912转录的影响， TY912附近的染色质结构和TY的切除 除Ty912以外的元素。 几条证据表明，三角洲层序是 Ty元素间复合的优先位置。检查角色的步骤 在三角洲的Ty重组中，我们将研究 缺少德尔塔元素的TY元素。

The long term goal of this research project is an understanding of the molecule mechanisms of genetic recombination in yeast. In the experiments presented in this proposal, we will isolate and characterize yeast DNA sequences which act as preferred sites for the initiation of recombination events. In addition, we will examine the recombination of yeast transposable elements and the interaction of these sequences with a repressor of recombination. Genetic recombination events are not uniformly distributed along the chromosome; instead, there exist special sites (hotspots) which act as localized stimulators of genetic exchange. It is our goal to isolate yeast recombination hotspots and to examine their mechanism of action. We have already shown that DNA sequence present in the ribosomal RNA gene cluster contains a recombination hotspot. The specific aims of the experiments presented in this proposal are: (1) to examine the mechanism of action of the hotspot present in ribosomal DNA, (2) to isolate additional sequences which act as recombination hotspots and (3) to isolate mutations in the genes whose products initiate recombination events at hotspots. Yeast Ty (transposon yeast) elements can be excised from the yeast genome by recombination between the terminally repeated Delta sequences present at their ends. The SPM2 gene product inhibits the excision of at least one transposon, known as Ty912. In order to examine the mechanism of action of the SPM2 gene product, we will determine its effect on Ty912 transcription, on chromatin structure in an around Ty912 and on the excision of Ty elements other than Ty912. Several lines of evidence suggest that the Delta sequences are the preferred sites of recombination between Ty elements. To examine the role of the Delta's in Ty recombination, we will examine recombination between Ty elements which lack Delta's.