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

• Applicant: Professorin Dr. Ulrike Zentgraf
• Subject Area: Basic Research in Biology and Medicine
• Term: from 1998 to 2001
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5106436

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.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1050: Funktionelle Architektur des Zellkerns