Functional Genomics of Maize Centromeres

着丝粒是一长段DNA，与一组被称为着丝点蛋白的蛋白质一起，负责确保染色体准确分离并传递给下一代。先前的工作已经证明着丝粒主要由重复的DNA序列组成。并不是所有的重复都是必需的，因为可以在不影响染色体分离的情况下去除着丝粒的大部分。在该奖项下进行的研究旨在确定玉米着丝粒中哪些DNA序列直接负责染色体分离。为此，将对约400,000个碱基对的着丝粒DNA样本进行测序，以确定着丝粒的基本组织。每一类独特的DNA序列（无论是重复的还是单拷贝的）将根据其在10条玉米染色体中的分布及其与玉米着丝点蛋白的相互作用进行分析。基于这些数据，人造着丝粒将从天然着丝粒的选定部分中产生，以测试它们在转基因玉米植物中的活性。在项目的最后阶段，人工着丝粒将被用来制造完全自主的人工染色体。这种人工染色体可以作为携带重要农艺学基因的载体，并且可以大大改进现有的将基因转移到植物中的方法。

Centromeres are long stretches of DNA that, along with a set of proteins known as kinetochore proteins, are responsible for ensuring that chromosomes are accurately segregated and passed on to the next generation. Previous work has demonstrated that centromeres are composed primarily of repeated DNA sequences. Not all of the repeats are required because large sections of a centromere can be removed without affecting chromosome segregation. Research carried out under this award is designed to identify which of the DNA sequences in the maize centromere are directly responsible for chromosome segregation. Towards this end, a sample of ~400,000 base pairs of centromeric DNA will be sequenced to determine the basic organization of the centromere. Each unique class of DNA sequence (either repetitive or single-copy) will be analyzed with respect to its distribution among the ten maize chromosomes and its interaction with a maize kinetochore protein. Based on these data, artificial centromeres will be created from selected portions of natural centromeres to test their activity in transgenic maize plants. In the final stages of the project, artificial centromeres will be used to create fully autonomous artificial chromosomes. Such artificial chromosomes could be used as vehicles for carrying agronomically important genes and could greatly improve existing methods for transferring genes into plants.