Natural variation in nucleolar dominance reveals the relationship between nucleolus organizer chromatin topology and rRNA gene transcription in Arabidopsis

• DOI: 10.1073/pnas.1932522100
• Publication Date: 2003-10-01T19:44:34Z
• Authors: Olga Pontes; Richard J. Lawrence; Nuno Neves; Manuela Silva; Jae-Hyeok Lee; Z. Jeffrey Chen; Wanda Viegas; Craig S. Pikaard
• Keywords: Transcription

In genetic hybrids, nucleolus formation on chromosomes inherited from only one parent is the epigenetic phenomenon, nucleolar dominance. By using Arabidopsis suecica , allotetraploid hybrid of thaliana and arenosa natural variation in dominance was found to occur, providing a unique opportunity examine homologous organizer regions (NORs) their active inactive states. A. strain LC1, NORs derived are active, whereas -derived silenced. 9502, both parental species active. When partially, but not fully, decondensed. Both LC1 colocalize with nucleolus, contradicting long-standing assumption that rRNA gene transcription drives association. Collectively, these observations clarify relationships among NOR chromatin topology, transcription, NOR–nucleolus associations. strains 9502 have each lost pair during evolution, amplified fragment-length polymorphism analysis further indicates genetically very similar. These data suggest can result subtle or trait fundamental given interspecies combination.