MOLECULAR MECHANISM OF GENETIC RECOMBINATION IN YEAST

本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 在这个建议中，我们将分离和表征酵母DNA 作为重组起始的优选位点的序列 事件 此外，我们将研究酵母的重组 转座因子以及这些序列与 重组阻遏物。 基因重组事件并不是沿着 染色体;相反，存在特殊的位点（热点）， 基因交换的局部刺激物。 我们的目标是分离酵母菌 重组热点，并检查其作用机制。 我们有 已经表明核糖体RNA基因簇中存在的DNA序列 含有重组热点。 实验的具体目的 本建议中提出的是：（1）研究 核糖体DNA中存在热点，（2）分离额外的序列 其充当重组热点，以及（3）分离重组热点中的突变。 其产物在热点处启动重组事件的基因。 酵母Ty（转座子酵母）元件可以从酵母基因组中切除 通过存在于 他们的结局 SPM 2基因产物抑制至少一个 转座子Ty 912 为了研究的作用机制， SPM 2基因产物，我们将确定其对Ty 912转录的影响， 对Ty 912周围的染色质结构和Ty的切除进行了研究 除Ty 912外的其他元素。 几条证据表明，三角洲序列是 Ty元件之间重组的优选位点。 为了检查角色 在Ty重组中的Delta，我们将研究 缺乏德尔塔的元素。

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.