Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.5/2408
Título: Natural variation in nucleolar dominance reveals relationship between nucleolus organizer chromatin topology and rRNA gene transcription in Arabidopsis
Autor: Silva, Manuela
Viegas, Wanda
Pontes, Olga
Lawrence, Richard
Neves, Nuno
Lee, Jae-Hyeok
Chen, Z.
Pikaard, Craig
Palavras-chave: nucleolar dominance
Data: Set-2003
Editora: PNAS
Citação: "PNAS". 100: 20 (2003). 11418-11423
Resumo: In genetic hybrids, nucleolus formation on chromosomes inherited from only one parent is the epigenetic phenomenon, nucleolar dominance. By using Arabidopsis suecica, the allotetraploid hybrid of Arabidopsis thaliana and Arabidopsis arenosa, natural variation in nucleolar dominance was found to occur, providing a unique opportunity to examine homologous nucleolus organizer regions (NORs) in their active and inactive states. In A. suecica strain LC1, NORs derived from A. arenosa are active, whereas A. thalianaderived NORs are silenced. In A. suecica strain 9502, NORs of both parental species are active. When active, NORs are partially, but not fully, decondensed. Both active and inactive LC1 NORs colocalize with the nucleolus, contradicting the long-standing assumption that rRNA gene transcription drives nucleolus association. Collectively, these observations clarify the relationships among NOR chromatin topology, rRNA gene transcription, and NOR–nucleolus associations. A. suecica strains LC1 and 9502 have each lost one pair of A. thaliana NORs during evolution, and amplified fragmentlength polymorphism analysis further indicates that these strains are genetically very similar. These data suggest that nucleolar dominance can result from subtle genetic or epigenetic variation but is not a trait fundamental to a given interspecies hybrid combination
URI: http://hdl.handle.net/10400.5/2408
Versão do Editor: www.pnas.org/cgi/doi/10.1073/pnas.1932522100
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