Evidence for a Role of <i>Arabidopsis</i> CDT1 Proteins in Gametophyte Development and Maintenance of Genome Integrity

Domenichini, Séverine; Benhamed, Moussa; Jaeger, Geert De; Slijke, Eveline Van De; Blanchet, Sophie; Bourge, Mickaël; Veylder, Lieven De; Bergounioux, Catherine; Raynaud, Cécile

doi:10.1105/tpc.112.100156

Cited by 24 publications

(22 citation statements)

References 53 publications

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“…In Arabidopsis, downregulation of AtCDT1a and AtCDT1b affects both nuclear DNA replication and plastid division via increased endoreduplication (DePamphilis, ). AtCDT1a is also required for gametophyte development (Domenichini et al ., ). Over‐expression of AtCDC6a leads to increased DNA ploidy in somatic cells, implying that AtCDC6a is critical for maintaining endoreplication (Castellano et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Arabidopsis replication factor C4 is critical for DNA replication during the mitotic cell cycle

Qian

Chen

et al. 2018

The Plant Journal

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Replication factor C (RFC) is a conserved eukaryotic complex consisting of RFC1/2/3/4/5. It plays important roles in DNA replication and the cell cycle in yeast and fruit fly. However, it is not very clear how RFC subunits function in higher plants, except for the Arabidopsis (At) subunits AtRFC1 and AtRFC3. In this study, we investigated the functions of AtRFC4 and found that loss of function of AtRFC4 led to an early sporophyte lethality that initiated as early as the elongated zygote stage, all defective embryos arrested at the two- to four-cell embryo proper stage, and the endosperm possessed six to eight free nuclei. Complementation of rfc4-1/+ with AtRFC4 expression driven through the embryo-specific DD45pro and ABI3pro or the endosperm-specific FIS2pro could not completely restore the defective embryo or endosperm, whereas a combination of these three promoters in rfc4-1/+ enabled the aborted ovules to develop into viable seeds. This suggests that AtRFC4 functions simultaneously in endosperm and embryo and that the proliferation of endosperm is critical for embryo maturation. Assays of DNA content in rfc4-1/+ verified that DNA replication was disrupted in endosperm and embryo, resulting in blocked mitosis. Moreover, we observed a decreased proportion of late S-phase and M-phase cells in the rfc4-1/- seedlings, suggesting that incomplete DNA replication triggered cell cycle arrest in cells of the root apical meristem. Therefore, we conclude that AtRFC4 is a crucial gene for DNA replication.

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Section: Discussionmentioning

confidence: 97%

Arabidopsis replication factor C4 is critical for DNA replication during the mitotic cell cycle

Qian

Chen

et al. 2018

The Plant Journal

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“…To determine the nucleic content of pollen grains, DAPI staining was performed as described by Domenichini et al . (). Images were captured using an epifluorescence microscope (Axioskop; Carl Zeiss) with a cooled CCD camera (Spot RT slider; Diagnostic Instruments Inc., USA, http://www.spotimaging.com) and Z ‐stack projections (maximum intensity) were performed using imagej software (http://imagej.nih.gov/ij).…”

Section: Methodsmentioning

confidence: 97%

The impact of Arabidopsis thaliana SNF1‐related‐kinase 1 (SnRK1)‐activating kinase 1 (SnAK1) and SnAK2 on SnRK1 phosphorylation status: characterization of a SnAK double mutant

et al. 2017

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Arabidopsis thaliana SNF1-related-kinase 1 (SnRK1)-activating kinase 1 (AtSnAK1) and AtSnAK2 have been shown to phosphorylate in vitro and activate the energy signalling integrator, SnRK1. To clarify this signalling cascade in planta, a genetic- and molecular-based approach was developed. Homozygous single AtSnAK1 and AtSnAK2 T-DNA insertional mutants did not display an apparent phenotype. Crossing of the single mutants did not allow the isolation of double-mutant plants, whereas self-pollinating the S1-/- S2+/- sesquimutant specifically gave approximatively 22% individuals in their offspring that, when rescued on sugar-supplemented media in vitro, were shown to be AtSnAK1 AtSnAK2 double mutants. Interestingly, this was not obtained in the case of the other sesquimutant, S1+/- S2-/-. Although reduced in size, the double mutant had the capacity to produce flowers, but not seeds. Immunological characterization established the T-loop of the SnRK1 catalytic subunit to be non-phosphorylated in the absence of both SnAKs. When the double mutant was complemented with a DNA construct containing an AtSnAK2 open reading frame driven by its own promoter, a normal phenotype was restored. Therefore, wild-type plant growth and development is dependent on the presence of SnAK in vivo, and this is correlated with SnRK1 phosphorylation. These data show that both SnAKs are kinases phosphorylating SnRK1, and thereby they contribute to energy signalling in planta.

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“…In Arabidopsis, two homologous genes, CDT1a and CDT1b , have been identified (Masuda et al ., ). The cdt1a mutant shows a partially gametophytic‐lethal phenotype, and this lethality is enhanced when cdt1a is combined with the cdt1b mutation (Domenichini et al ., ); silencing of both CDT1a and CDT1b inhibited nuclear DNA replication and plastid division (Raynaud et al ., ). Ectopic expression of CDT1a enhanced endoreplication, indicating another function in DNA polyploidization (Castellano et al ., ).…”

Section: Introductionmentioning

confidence: 99%

A dual‐color marker system for in vivo visualization of cell cycle progression in Arabidopsis

et al. 2014

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SUMMARYVisualization of the spatiotemporal pattern of cell division is crucial to understand how multicellular organisms develop and how they modify their growth in response to varying environmental conditions. The mitotic cell cycle consists of four phases: S (DNA replication), M (mitosis and cytokinesis), and the intervening G1 and G2 phases; however, only G2/M-specific markers are currently available in plants, making it difficult to measure cell cycle duration and to analyze changes in cell cycle progression in living tissues. Here, we developed another cell cycle marker that labels S-phase cells by manipulating Arabidopsis CDT1a, which functions in DNA replication origin licensing. Truncations of the CDT1a coding sequence revealed that its carboxy-terminal region is responsible for proteasome-mediated degradation at late G2 or in early mitosis. We therefore expressed this region as a red fluorescent protein fusion protein under the S-specific promoter of a histone 3.1-type gene, HISTONE THREE RELATED2 (HTR2), to generate an S/G2 marker. Combining this marker with the G2/M-specific CYCB1-GFP marker enabled us to visualize both S to G2 and G2 to M cell cycle stages, and thus yielded an essential tool for time-lapse imaging of cell cycle progression. The resultant dual-color marker system, Cell Cycle Tracking in Plant Cells (Cytrap), also allowed us to identify root cells in the last mitotic cell cycle before they entered the endocycle. Our results demonstrate that Cytrap is a powerful tool for in vivo monitoring of the plant cell cycle, and thus for deepening our understanding of cell cycle regulation in particular cell types during organ development.

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Evidence for a Role of Arabidopsis CDT1 Proteins in Gametophyte Development and Maintenance of Genome Integrity

Cited by 24 publications

References 53 publications

Arabidopsis replication factor C4 is critical for DNA replication during the mitotic cell cycle

Arabidopsis replication factor C4 is critical for DNA replication during the mitotic cell cycle

The impact of Arabidopsis thaliana SNF1‐related‐kinase 1 (SnRK1)‐activating kinase 1 (SnAK1) and SnAK2 on SnRK1 phosphorylation status: characterization of a SnAK double mutant

A dual‐color marker system for in vivo visualization of cell cycle progression in Arabidopsis

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