Ross Sozzani: The Goldilocks principle, just the right amount of growth

Stem cells are the source of different cell types, and the balance between stem cell self-renewal and differentiation of their progeny regulates the overall growth of an organ. Disruption of this balance can lead to unchecked growth, producing tumors or deformed organs. We have used the Arabidopsis root, characterized by the presence of a spatially confined stem cell niche, to gain a coherent qualitative and quantitative understanding of stem cell regulation. In the root apical meristem, we know many of the key players controlling specific stem cells. Yet, we lack an understanding of the regulatory programs and emergent signaling that leads to stem cell fate. Using techniques derived from biological, mathematical, and engineering science we have unraveled the mechanisms that regulate plant stem cell fate, maintenance, and behavior as a whole. Identifying and mathematically characterizing the “rules” controlling stem cells, for example identifying the interacting components of the stem cell signaling pathway, is a key step in controlling growth and development of plant organisms. To this end, we have used predictive models towards fundamental understanding of biological systems and relationships at a multi-scale level.