Die Variabilität der Kerndomänen und der DNA-Proteinstruktur von Telomeren während der pflanzlichen Entwicklung Varibility of the nuclear domains and the DNA-protein structure of telomeres during plant development

植物发育过程中核结构域和端粒 DNA-蛋白质结构的变异

• 批准号: 5106436
• 负责人: Professorin Dr. Ulrike Zentgraf
• 金额: --
• 依托单位: Abteilung für Allgemeine Genetik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 1998
• 资助国家: 德国
• 起止时间: 1997-12-31 至 2000-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5106436?language=en
• 关键词: Die; Variabilit; der; Kerndom; nen

Telomeres are the DNA-protein complexes found at the termini of eukaryotic chromosomes and are required for several important cellular functions. They are involved in the segregation of the chromosomes during mitosis, they prevent the chromosomes from degradation and end-to-end fusions, and they enable complete replication of linear DNA by a specific ribozyme, the telomerase. In yeast, telomeres also exhibit poistion effects on the transcription of genes located in close proximity to the telomeres as well as on the timing of DNA replication. Telomeres are not randomly distributed within the nucleus but localised to certain nuclear compartments probably constituting an independent functional domain within the nucleus. For Arabidopsis thaliana we were able to show the localisation of most of the telomeres around the nucleolus in young root cells. This specific localisation around the nucleolus was lost and became dispersed with increasing age of the cells. Furthermore, we could show, that telomeric DNA forms a stable complex with a specific protein (ATBP1). Here again, the composition of the telomeric DNA-protein complex exhibits a developmental dynamic, an additional protein (ATBP2) binds to this complex via protein/protein interaction during the onset of leaf senescence. ATBP1 and ATBP2 should now be purified and characterised more precisely. Changes in chromatin structure and composition of the DNA-protein complexes of the Arabidopsis thaliana telomeres during other stages of plant development will be investigated and our main interest wil focus on the functional implication of this specific nuclear localisation and on the correlation between changes in this nuclear localisation and the dynamic of the DNA-protein interaction at the telomeres.

端粒是在真核染色体末端发现的 DNA-蛋白质复合物，是多种重要细胞功能所必需的。它们参与有丝分裂过程中染色体的分离，防止染色体降解和端到端融合，并且能够通过特定的核酶（端粒酶）完全复制线性 DNA。在酵母中，端粒还对靠近端粒的基因转录以及 DNA 复制的时间表现出位置效应。端粒不是随机分布在细胞核内，而是定位于某些核区室，可能构成细胞核内的独立功能域。对于拟南芥，我们能够显示年轻根细胞中核仁周围大部分端粒的定位。随着细胞年龄的增长，核仁周围的这种特定定位消失并变得分散。此外，我们还可以证明，端粒 DNA 与特定蛋白质 (ATBP1) 形成稳定的复合物。在这里，端粒 DNA-蛋白质复合物的组成再次表现出发育动态，在叶子衰老开始期间，额外的蛋白质 (ATBP2) 通过蛋白质/蛋白质相互作用与该复合物结合。现在应该对 ATBP1 和 ATBP2 进行更精确的纯化和表征。我们将研究拟南芥端粒在植物发育其他阶段的染色质结构和 DNA-蛋白质复合物组成的变化，我们的主要兴趣将集中在这种特定核定位的功能含义以及这种核定位变化之间的相关性上。端粒处DNA-蛋白质相互作用的定位和动态。