PLoS Biology (Nov 2013)

A SCARECROW-RETINOBLASTOMA protein network controls protective quiescence in the Arabidopsis root stem cell organizer.

  • Alfredo Cruz-Ramírez,
  • Sara Díaz-Triviño,
  • Guy Wachsman,
  • Yujuan Du,
  • Mario Arteága-Vázquez,
  • Hongtao Zhang,
  • Rene Benjamins,
  • Ikram Blilou,
  • Anne B Neef,
  • Vicki Chandler,
  • Ben Scheres

DOI
https://doi.org/10.1371/journal.pbio.1001724
Journal volume & issue
Vol. 11, no. 11
p. e1001724

Abstract

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Quiescent long-term somatic stem cells reside in plant and animal stem cell niches. Within the Arabidopsis root stem cell population, the Quiescent Centre (QC), which contains slowly dividing cells, maintains surrounding short-term stem cells and may act as a long-term reservoir for stem cells. The RETINOBLASTOMA-RELATED (RBR) protein cell-autonomously reinforces mitotic quiescence in the QC. RBR interacts with the stem cell transcription factor SCARECROW (SCR) through an LxCxE motif. Disruption of this interaction by point mutation in SCR or RBR promotes asymmetric divisions in the QC that renew short-term stem cells. Analysis of the in vivo role of quiescence in the root stem cell niche reveals that slow cycling within the QC is not needed for structural integrity of the niche but allows the growing root to cope with DNA damage.