A bistable circuit involving SCARECROW-RETINOBLASTOMA integrates cues to inform asymmetric stem cell division.

Journal Article (Academic article)

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.

Full Text

Duke Authors

Cited Authors

  • Cruz Ramírez, A; Díaz Triviño, S; Blilou, I; Grieneisen, VA; Sozzani, R; Zamioudis, C; Miskolczi, P; Nieuwland, J; Benjamins, R; Dhonukshe, P; Caballero Pérez, J; Horvath, B; Long, Y; Mähönen, AP; Zhang, H; Xu, J; Murray, JA; Benfey, PN; Bako, L; Marée, AF; Scheres, B

Published Date

  • August 2012

Published In

Volume / Issue

  • 150 / 5

Start / End Page

  • 1002 - 1015

PubMed ID

  • 22921914

Pubmed Central ID

  • PMC3500399

International Standard Serial Number (ISSN)

  • 1097-4172

Digital Object Identifier (DOI)

  • 10.1016/j.cell.2012.07.017


  • English