A General G1/S-Phase Cell-Cycle Control Module in the Flowering Plant Arabidopsis thaliana
Open Access
- 2 August 2012
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLoS Genetics
- Vol. 8 (8), e1002847
- https://doi.org/10.1371/journal.pgen.1002847
Abstract
The decision to replicate its DNA is of crucial importance for every cell and, in many organisms, is decisive for the progression through the entire cell cycle. A comparison of animals versus yeast has shown that, although most of the involved cell-cycle regulators are divergent in both clades, they fulfill a similar role and the overall network topology of G1/S regulation is highly conserved. Using germline development as a model system, we identified a regulatory cascade controlling entry into S phase in the flowering plant Arabidopsis thaliana, which, as a member of the Plantae supergroup, is phylogenetically only distantly related to Opisthokonts such as yeast and animals. This module comprises the Arabidopsis homologs of the animal transcription factor E2F, the plant homolog of the animal transcriptional repressor Retinoblastoma (Rb)-related 1 (RBR1), the plant-specific F-box protein F-BOX-LIKE 17 (FBL17), the plant specific cyclin-dependent kinase (CDK) inhibitors KRPs, as well as CDKA;1, the plant homolog of the yeast and animal Cdc2+/Cdk1 kinases. Our data show that the principle of a double negative wiring of Rb proteins is highly conserved, likely representing a universal mechanism in eukaryotic cell-cycle control. However, this negative feedback of Rb proteins is differently implemented in plants as it is brought about through a quadruple negative regulation centered around the F-box protein FBL17 that mediates the degradation of CDK inhibitors but is itself directly repressed by Rb. Biomathematical simulations and subsequent experimental confirmation of computational predictions revealed that this regulatory circuit can give rise to hysteresis highlighting the here identified dosage sensitivity of CDK inhibitors in this network. In order to grow, multicellular organisms need to multiply their cells. Cell proliferation is achieved through a complex order of events called the cell cycle, during which the nuclear DNA is duplicated and subsequently distributed to the newly forming daughter cells. The decision to replicate the nuclear DNA is in many organisms crucial to progress through the entire cell cycle. Alterations of the cell cycle, especially at the entry point, can cause severe developmental defects and are often causal for maladies, such as cancer. Substantial work in yeast and animals has revealed the regulatory steps controlling S-phase entry. In contrast, relatively little is known about the plant cell cycle despite plants being one of the largest classes of living organisms and despite the importance of plants for human life, for instance as the basis of human nutrition. Our work presents a molecular framework of core cell-cycle regulation for entry into the DNA replication phase in the model plant Arabidopsis. We report here the identification of a regulatory cascade that likely functions in many plant cells and organisms. With this, we also provide an important basis for comparative analyses of cell-cycle control between different eukaryotes, such as yeast and mammals.Keywords
This publication has 73 references indexed in Scilit:
- Evolution of networks and sequences in eukaryotic cell cycle controlPhilosophical Transactions Of The Royal Society B-Biological Sciences, 2011
- CULLIN 4-RING FINGER-LIGASE plays a key role in the control of endoreplication cycles in Arabidopsis trichomesProceedings of the National Academy of Sciences of the United States of America, 2010
- Putative Arabidopsis Transcriptional Adaptor Protein (PROPORZ1) is required to modulate histone acetylation in response to auxinProceedings of the National Academy of Sciences of the United States of America, 2010
- Proliferation and cell fate establishment during Arabidopsis male gametogenesis depends on the Retinoblastoma proteinProceedings of the National Academy of Sciences of the United States of America, 2009
- Amplification efficiency: linking baseline and bias in the analysis of quantitative PCR dataNucleic Acids Research, 2009
- Positive feedback of G1 cyclins ensures coherent cell cycle entryNature, 2008
- Regulation of Cell Division by Intrinsically Unstructured Proteins: Intrinsic Flexibility, Modularity, and Signaling ConduitsBiochemistry, 2008
- Analysis of the Subcellular Localization, Function, and Proteolytic Control of the Arabidopsis Cyclin-Dependent Kinase Inhibitor ICK1/KRP1Plant Physiology, 2006
- Intrinsically unstructured proteins and their functionsNature Reviews Molecular Cell Biology, 2005
- Control of petal and pollen development by the plant cyclin-dependent kinase inhibitor ICK1 in transgenic Brassica plantsPlanta, 2002