Applied & Computational Mathematics seminar: Cellular pattering in plants: Who is the master of a cell's fate?

Speaker: Nicholas Russell, Max Planck Institute of Plant Breeding Research

Title:  Cellular pattering in plants: Who is the master of a cell's fate?

Abstract:  How cell fate decisions are made through complex gene regulatory networks (GRNs) has been an important field of study. However, how these GRNs persist and maintain differentiated cell status has been less studied, even though this is crucial to the physiology and survival of living organisms as they develop. In the Arabidopsis thaliana sepal epidermis, there are two main cell types: small cells and giant cells. Giant cells endoreduplicate, i.e., skip mitosis, duplicate their chromosomes multiple times, and grow to large sizes. We have previously proposed a cell-autonomous, stochastic mechanism for giant cell fate specification, in which a transcription factor, ATML1, upregulates a cyclin-dependent kinase inhibitor, LGO, which in turn specifies giant cell identity. How ATML1 and LGO may be involved in maintaining the giant cell fate identity after giant cell fate specification was unknown. In this work, by using advanced experimental and imaging techniques, quantitative image analysis, mathematical modeling, and numerical simulations, we propose that a double positive feedback loop on ATML1 is crucial for the cell fate specification process, and it is also responsible for maintaining the giant cell fate. We construct an analytical and stochastic computational model of giant cell fate decision-making in a growing and dividing tissue, recapitulating our experiments showing giant cell de-differentiation. Our work mechanistically provides a clear example of how a given regulatory circuit can operate for both the cell fate decision-making process and cell fate maintenance.

Time:  Tuesday, September 10 – 11:00am – 12:00pm

Place:  Johnson Center, Meeting Room F and  Zoom