A bistable circuit involving SCARECROW-RETINOBLASTOMA integrates cues to inform asymmetric stem cell division.
Cell
; 150(5): 1002-15, 2012 Aug 31.
Article
em En
| MEDLINE
| ID: mdl-22921914
ABSTRACT
In plants, where cells cannot migrate, asymmetric cell divisions (ACDs) must be confined to the appropriate spatial context. We investigate tissue-generating asymmetric divisions in a stem cell daughter within the Arabidopsis root. Spatial restriction of these divisions requires physical binding of the stem cell regulator SCARECROW (SCR) by the RETINOBLASTOMA-RELATED (RBR) protein. In the stem cell niche, SCR activity is counteracted by phosphorylation of RBR through a cyclinD6;1-CDK complex. This cyclin is itself under transcriptional control of SCR and its partner SHORT ROOT (SHR), creating a robust bistable circuit with either high or low SHR-SCR complex activity. Auxin biases this circuit by promoting CYCD6;1 transcription. Mathematical modeling shows that ACDs are only switched on after integration of radial and longitudinal information, determined by SHR and auxin distribution, respectively. Coupling of cell-cycle progression to protein degradation resets the circuit, resulting in a "flip flop" that constrains asymmetric cell division to the stem cell region.
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Base de dados:
MEDLINE
Assunto principal:
Arabidopsis
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Raízes de Plantas
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Proteínas de Arabidopsis
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article