Homologous Recombination in Arabidopsis Induced by HO Endonuclease

染色体的完整性和多样性是通过重组来维持的，然而，人们对这种机制是如何合理地发挥作用的，尤其是在植物中，知之甚少。在拟南芥中，一个诱导有丝分裂重组的系统已经被开发出来，在这个系统中，一个单一的，明确的，DNA双链断裂被传递到染色体的特定位点。酵母HO内切酶是一种位点特异性DNA内切酶的靶位点，它被克隆到一个独特的染色体位置，并在植物中通过克隆的HO基因的表达诱导断裂。具体目的是：1)验证拟南芥减数分裂中染色体双链断裂可以诱导同源重组的假设；2)确定植物染色体DNA双链断裂是否可以刺激有丝分裂和减数分裂中的异位重组。这项以拟南芥为研究对象的研究将有助于更好地了解植物染色体重组的基本机制。此外，任何朝着实现植物特异位点重组目标的进展都将对基础研究和应用研究产生重大影响。

Ray 9630402 The integrity, as well as the diversity of chromosomes, is maintained by recombination and yet little is known about how this mechanism is judiciously performed, particularly in plants. A system of induced mitotic recombination in Arabidopsis thaliana, in which a single, defined, DNA double strand break is delivered to the chromosome at a particular locus has been developed. The target site of a site-specific DNA endonuclease, HO endonuclease of yeast, is cloned into a unique chromosomal location and the break induced by the expression of a cloned HO gene in the plant. Specific objectives are 1) to test the hypothesis that a chromosomal double strand break in meiosis can induce homologous recombination in Arabidopsis and 2) to determine whether ectopic recombination can be stimulated in mitosis and meiosis by a DNA double strand break in the plant chromosome. %%% A better understanding of the basic mechanisms involved in recombination of plant chromosomes will result from this study using the model plant, Arabidopsis thalania. Moreover, any movement toward the goal of achieving site-specific recombination in plants will have significant impact in both basic and applied research.