SGER: Epigenetic Consequences of Telomere Dysfunction In Plants

0104339多萝西·希彭端粒对于基因组的稳定和在未分化和去分化状态下的持续增殖是必不可少的。拟南芥是阐明端粒在植物生长发育中的作用以及解决高等真核生物端粒功能基本问题的有用模型。这位研究人员最近证明，在没有端粒酶的情况下，拟南芥可以存活长达10代。端粒酶是一种负责维持染色体末端端粒DNA片段的酶。在端粒酶缺失的植物中，端粒逐渐缩短，晚代突变体承受越来越多的细胞遗传学损伤，这与营养器官和生殖器官的发育异常有关。出乎意料的是，端粒酶缺陷植物的一个重要子集表现出不同的表型，包括花器官和沿纵轴卷曲的叶片的同源同源转化。这一表型与拟南芥染色质结构缺陷突变体的惊人相似性强烈表明，端粒功能障碍可以导致基因表达调控的全球表观遗传反应。该项目将测试端粒侵蚀是否伴随着核结构和染色质结构的变化，并揭示在连续几代端粒酶缺乏症期间的全球转录图谱。

0104339 Dorothy ShippenTelomeres are essential for genome stability and continued proliferation in an undifferentiated and dedifferentiated state. Arabidopsis thaliana is a useful model to elucidate the role of telomeres in plant growth and development and to address fundamental questions of telomere function in higher eukaryotes. The investigator recently demonstrated that Arabidopsis can survive up to ten generations without telomerase, the enzyme responsible for maintaining tracts of telomeric DNA on chromosome ends. In telomerase-deficient plants, telomeres shorten progressively and late generation mutants endure increasing levels of cytogenetic damage, correlated with developmental anomalies in vegetative and reproductive organs. Unexpectedly, a significant subset of telomerase-deficient plants show a different phenotype that includes homeotic transformation in floral organs and leaves that curl up along the longitudinal axis. The striking similarity of this phenotype to mutants defective in aspects of chromatin structure in Arabidopsis strongly suggests that telomere dysfunction can lead to global epigenetic repercussions in the regulation of gene expression. This project will test whether telomere erosion is accompanied by changes in nuclear architecture and chromatin structure and to reveal the global transcription profile during successive generations of a telomerase deficiency.