Cell size and growth regulation in the Arabidopsis thaliana apical stem cell niche

Research output: Contribution to journalArticle

Abstract

Cell size and growth kinetics are fundamental cellular properties with important physiological implications. Classical studies on yeast, and recently on bacteria, have identified rules for cell size regulation in single cells, but in the more complex environment of multicellular tissues, data have been lacking. In this study, to characterize cell size and growth regulation in a multicellular context, we developed a 4D imaging pipeline and applied it to track and quantify epidermal cells over 3-4 d in Arabidopsis thaliana shoot apical meristems. We found that a cell size checkpoint is not the trigger for G2/M or cytokinesis, refuting the unexamined assumption that meristematic cells trigger cell cycle phases upon reaching a critical size. Our data also rule out models in which cells undergo G2/M at a fixed time after birth, or by adding a critical size increment between G2/M transitions. Rather, cell size regulation was intermediate between the critical size and critical increment paradigms, meaning that cell size fluctuations decay by ∼75% in one generation compared with 100% (critical size) and 50% (critical increment). Notably, this behavior was independent of local cell-cell contact topologies and of position within the tissue. Cells grew exponentially throughout the first >80% of the cell cycle, but following an asymmetrical division, the small daughter grew at a faster exponential rate than the large daughter, an observation that potentially challenges present models of growth regulation. These growth and division behaviors place strong constraints on quantitative mechanistic descriptions of the cell cycle and growth control.

Details

Authors
  • Lisa Willis
  • Yassin Refahi
  • Raymond Wightman
  • Benoit Landrein
  • José Teles
  • Kerwyn Casey Huang
  • Elliot M. Meyerowitz
  • Henrik Jönsson
Organisations
External organisations
  • University of Cambridge
  • California Institute of Technology
  • Stanford University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Cell Biology

Keywords

  • Cell cycle, Cell growth, Cell size, Homeostasis, Plant stem cells
Original languageEnglish
Pages (from-to)E8238-E8246
JournalProceedings of the National Academy of Sciences of the United States of America
Volume113
Issue number51
Publication statusPublished - 2016 Dec 20
Publication categoryResearch
Peer-reviewedYes