SGER: Epigenetic Consequences of Telomere Dysfunction In Plants

Dorothy ShippenTelomeres对于基因组的稳定性和在未分化和去分化状态下的持续增殖是必不可少的。 拟南芥是研究端粒在植物生长发育中的作用和高等真核生物端粒功能的重要模型。 研究人员最近证明，拟南芥可以在没有端粒酶的情况下存活10代，端粒酶负责维持染色体末端的端粒DNA片段。 在端粒缺失的植物中，端粒逐渐缩短，并且晚代突变体承受越来越高水平的细胞遗传学损伤，这与营养和生殖器官的发育异常相关。 出乎意料的是，一个显着的子集的端粒酶缺陷型植物显示出不同的表型，包括同源异型转化花器官和叶片，卷曲沿着纵轴。 这种表型与拟南芥中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能导致基因表达调控中的全球表观遗传影响。 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，并揭示端粒酶缺陷连续几代期间的全球转录谱。

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.