Syracuse

Characterization of AtNUC-L1 reveals a central role of nucleolin in nucleolus organization and silencing of AtNUC-L2 gene in Arabidopsis.

Archive ouverte

Pontvianne, Frederic | Matía, Isabel | Douet, Julien | Tourmente, Sylvette | Medina, Francisco J | Echeverria, Manuel | Sáez-Vásquez, Julio

Edité par CCSD ; American Society for Cell Biology -

Nucleolin is one of the most abundant protein in the nucleolus and is a multifunctional protein involved in different steps of ribosome biogenesis. In contrast to animals and yeast, the genome of the model plant Arabidopsis thaliana encodes two nucleolin-like proteins, AtNUC-L1 and AtNUC-L2. However, only the AtNUC-L1 gene is ubiquitously expressed in normal growth conditions. Disruption of this AtNUC-L1 gene leads to severe plant growth and development defects. AtNUC-L1 is localized in the nucleolus, mainly in the dense fibrillar component. Absence of this protein in Atnuc-L1 plants induces nucleolar disorganization, nucleolus organizer region decondensation, and affects the accumulation levels of pre-rRNA precursors. Remarkably, in Atnuc-L1 plants the AtNUC-L2 gene is activated, suggesting that AtNUC-L2 might rescue, at least partially, the loss of AtNUC-L1. This work is the first description of a higher eukaryotic organism with a disrupted nucleolin-like gene and defines a new role for nucleolin in nucleolus structure and rDNA chromatin organization.

• Description
• Sujet/Public
• Outil
• Outil d'anticipation
• Mémoire et thèse
• Gestion