Weill Institute for Cell and Molecular Biology, Cornell University, United States; The graduate field of Genetics, Genomics, and Development, Cornell University, Ithaca, United States
Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom; Computational Biology and Biological Physics, Lund University, Lund, Sweden; Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom
Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom; Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom; Microsoft Research, Cambridge, United Kingdom
Weill Institute for Cell and Molecular Biology, Cornell University, United States; The graduate field of Genetics, Genomics, and Development, Cornell University, Ithaca, United States; Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, United States
Multicellular development produces patterns of specialized cell types. Yet, it is often unclear how individual cells within a field of identical cells initiate the patterning process. Using live imaging, quantitative image analyses and modeling, we show that during Arabidopsis thaliana sepal development, fluctuations in the concentration of the transcription factor ATML1 pattern a field of identical epidermal cells to differentiate into giant cells interspersed between smaller cells. We find that ATML1 is expressed in all epidermal cells. However, its level fluctuates in each of these cells. If ATML1 levels surpass a threshold during the G2 phase of the cell cycle, the cell will likely enter a state of endoreduplication and become giant. Otherwise, the cell divides. Our results demonstrate a fluctuation-driven patterning mechanism for how cell fate decisions can be initiated through a random yet tightly regulated process.
