Characterization of Arabidopsis Telomeres

端粒是形成真核生物染色体末端的特殊结构。这些结构对于基因组的复制和维持至关重要。端粒已经在低级真核生物中得到了广泛的研究，但对高级真核生物的端粒却知之甚少。最近，从开花植物拟南芥中克隆出了一个高级真核生物端粒，为研究这种生物的端粒区域作为模型系统提供了机会。将从端粒结构和功能两个方面进行研究。首先，将研究拟南芥端粒附近DNA序列的性质和组织。其次，断裂的染色体末端获得新端粒（即端粒愈合）的机制将使用携带愈合端粒的拟南芥染色体突变体进行研究。愈合的端粒将被分离出来，并将其结构与原始染色体位点进行比较，以确定愈合事件是如何发生的。此外，位于着丝粒近端的愈合端粒将作为研究拟南芥着丝粒结构的潜在工具进行研究。对染色体的基本结构成分的描述使我们对细胞维持正确染色体补体的机制有了更深入的了解。此外，这一信息在植物人工染色体工程中可能是有用的，这一技术将大大增加已经强大的可用分子技术的曲目。

Telomeres are the specialized structures that form the termini of eukaryotic chromosomes. These structures are essential for the replication and maintenance of the genome. Telomeres have been extensively studied in lower eukaryotes but considerably less in known about higher eukaryotic telomeres. A higher eukaryotic telomere has recently been cloned from the flowering plant Arabidopsis thaliana, providing the opportunity to study the telomeric regions of this organism as a model system. Two aspects of telomere structure and function will be studied. First, the nature and organization of the DNA sequences that lie adjacent to A. thaliana telomeres will be investigated. Second, the mechanism by which a broken chromosome end acquires a new telomere (i.e., telomere healing) will be studied using a chromosomal mutant of A. thaliana which carries a healed telomere. The healed telomere will be isolated and its structure compared to that of the original chromosomal site to determine how the healing event took place. In addition, the healed telomere, which resided proximal to a centromere, will be investigated as a potential tool for studying A. thaliana centromere structure. Characterization of essential structural components of chromosomes gives greater insight into a basic understanding of mechanisms used by cells to maintain the correct chromosome complement. Additionally, this information could be useful in engineering artificial chromosomes for plants, a technique which would add significantly to the already powerful repertoire of available molecular techniques.