| Autor: |
Boudolf, Véronique, Vlieghe, Kobe, Beemster, Gerrit T. S., Magyar, Zoltan, Acosta, Juan Antonio Torres, Maes, Sara, Van Der Schueren, Els, Inzé, Dirk, De Veylder, Lieven |
| Předmět: |
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| Zdroj: |
Plant Cell; Oct2004, Vol. 16 Issue 10, p2683-2692, 10p, 2 Color Photographs, 3 Diagrams, 2 Charts, 4 Graphs |
| Abstrakt: |
Transgenic Arabidopsis thaliana plants overproducing the E2Fa-DPa transcription factor have two distinct cell-specific phenotypes: some cells divide ectopically and others are stimulated to endocycle. The decision of cells to undergo extra mitotic divisions has been postulated to depend on the presence of a mitosis-inducing factor (MIF). Plants possess a unique class of cyclin-dependent kinases (CDKs; B-type) for which no ortholog is found in other kingdoms. The peak of CDKB1;1 activity around the G2-M boundary suggested that it might be part of the MIF. Plants that overexpressed a dominant negative allele of CDKB1;1 underwent enhanced endoreduplication, demonstrating that CDKB1;1 activity was required to inhibit the endocycle. Moreover, when the mutant CDKB1;1 allele was overexpressed in an E2Fa-DPa-overproducing background, it enhanced the endoreduplication phenotype, whereas the extra mitotic cell divisions normally induced by E2Fa-DPa were repressed. Surprisingly, CDKB1;1 transcription was controlled by the E2F pathway, as shown by its upregulation in E2Fa-DPa-overproducing plants and mutational analysis of the E2F binding site in the CDKB1;1 promoter. These findings illustrate a cross talking mechanism between the G1-S and G2-M transition points. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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