Résumé
The nucleolus is the site of rRNA gene transcription,rRNA processing, and ribosome biogenesis. How-ever, the nucleolus also plays additional roles in thecell. We isolated nucleoli using fluorescence-acti-vated cell sorting (FACS) and identified nucleolus-associated chromatin domains (NADs) by deep seq-uencing, comparing wild-type plants and null mutantsfor the nucleolar protein NUCLEOLIN 1 (NUC1). NADsare primarily genomic regions with heterochromaticsignatures and include transposable elements (TEs),sub-telomeric regions, and mostly inactive protein-coding genes. However, NADs also include activer RNA genes and the entire short arm of chromosome4 adjacent to them. Innuc1null mutants, which alterrRNA gene expression and overall nucleolar structure,NADs are altered, telomere association with thenucle-olus is decreased, and telomeres become shorter.Collectively, our studies reveal roles for NUC1 and the nucleolus in the spatial organization of chromosomes as well as telomere maintenance