Understanding the Molecular Mechanisms and Strategies of Size Regulation in Budding Yeast

Felix Barber, Graduate Student – Harvard University

Stories_insci Stories_insci on May 3, 2018

Felix Barber

Question
In less than 200 words, what main research questions are you working on? Please make sure to first include a brief context and background to your research, articulate your question(s) and conclude with why you think it’s important to study the them (i.e., the potential broader impacts).
Answer
Organisms from all domains of life display size regulation, that is, a coupling between growth and division to constrain the distribution of cell sizes in a population of cells. However, how this is done remains unclear. I’m trying to understand both the kind of molecular mechanisms cells use to regulate their size, and what effect this regulation has on cell fitness. To address this question I’m using the model organism budding yeast, and am using a combination of mathematical modeling and single cell measurements to understand how size influences passage through the cell cycle transition “Start”. I want to understand whether size couples to passage through Start through the dilution of an inhibitor of cell cycle progression, or via the accumulation of an activator of the same. Additionally, budding yeast is one of many organisms for which the kind of size regulation it displays is consistent with it adding a constant volume between birth and division. Although this “adder” behavior is phylogenetically widespread, we don’t understand whether this conveys some fitness advantage for cells. I am therefore additionally trying to understand the impact of size regulation on the population growth rate in asymmetrically dividing cells through mathematical modeling.  Learn More