17329565
Neyt Pia
2
Boccardi Tommaso Matteo
Fleury Delphine et al. 2007 Feb. Plant Cell 19(2):417-32.
Maere Steven
2007 Feb
417-32
Inzé Dirk
19
Anami Sylvester
Cnops Gerda
Nelissen Hilde
Van Lijsebettens Mieke
Beemster Gerrit T S
Chromatin modification and transcriptional activation are novel roles for E3 ubiquitin ligase proteins that have been mainly associated with ubiquitin-dependent proteolysis. We identified HISTONE MONOUBIQUITINATION1 (HUB1) (and its homolog HUB2) in Arabidopsis thaliana as RING E3 ligase proteins with a function in organ growth. We show that HUB1 is a functional homolog of the human and yeast BRE1 proteins because it monoubiquitinated histone H2B in an in vitro assay. Hub knockdown mutants had pale leaf coloration, modified leaf shape, reduced rosette biomass, and inhibited primary root growth. One of the alleles had been designated previously as ang4-1. Kinematic analysis of leaf and root growth together with flow cytometry revealed defects in cell cycle activities. The hub1-1 (ang4-1) mutation increased cell cycle duration in young leaves and caused an early entry into the endocycles. Transcript profiling of shoot apical tissues of hub1-1 (ang4-1) indicated that key regulators of the G2-to-M transition were misexpressed. Based on the mutant characterization, we postulate that HUB1 mediates gene activation and cell cycle regulation probably through chromatin modifications.
Fleury Delphine
Micol José Luis
The Arabidopsis thaliana homolog of yeast BRE1 has a function in cell cycle regulation during early leaf and root growth.
Himanen Kristiina
Robles Pedro