APC/C-CCS52A complexes control meristem maintenance in the Arabidopsis root.
Plant organs originate from meristems where stem cells are maintained to produce continuously daughter cells that are the source of different cell types. The cell cycle switch gene CCS52A, a substrate specific activator of the anaphase promoting complex/cyclosome (APC/C), controls the mitotic arrest and the transition of mitotic cycles to endoreduplication (ER) cycles as part of cell differentiation. Arabidopsis, unlike other organisms, contains 2 CCS52A isoforms. Here, we show that both of them are active and regulate meristem maintenance in the root tip, although through different mechanisms. The CCS52A1 activity in the elongation zone of the root stimulates ER and mitotic exit, and contributes to the border delineation between dividing and expanding cells. In contrast, CCS52A2 acts directly in the distal region of the root meristem to control identity of the quiescent center (QC) cells and stem cell maintenance. Cell proliferation assays in roots suggest that this control involves CCS52A2 mediated repression of mitotic activity in the QC cells. The data indicate that the CCS52A genes favor a low mitotic state in different cell types of the root tip that is required for meristem maintenance, and reveal a previously undescribed mechanism for APC/C mediated control in plant development.
Vanstraelen
Marleen
M
Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, Unité Propre de Recherche 2355, 91198 Gif-sur-Yvette cedex, France.
Baloban
Mikhail
M
Da Ines
Olivier
O
Cultrone
Antonietta
A
Lammens
Tim
T
Boudolf
Véronique
V
Brown
Spencer C
SC
De Veylder
Lieven
L
Mergaert
Peter
P
Kondorosi
Eva
E
D064173:Anaphase-Promoting Complex-Cyclosome; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D005434:Flow Cytometry; D005822:Genetic Vectors / Q000235:genetics; D017403:In Situ Hybridization; D018519:Meristem / Q000235:genetics / Q000502:physiology*; D008938:Mitosis / Q000502:physiology*; D018517:Plant Roots / Q000235:genetics / Q000502:physiology*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D043743:Ubiquitin-Protein Ligase Complexes / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C540491:FZR2 protein, Arabidopsis; D020033:Protein Isoforms; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome