PhD Proposal Exam – Medha Sharma – November 9th, 2017

PhD Proposal Exam

Thursday, November 9^th, 2017 at 2:10 pm – Ramsay Wright Building, Room 142

Medha Sharma (Harris lab)

“Mathematical modeling of the assembly and maintenance of non-contractile actomyosin rings in Drosophila embryos”

Abstract

Both contractile and non-contractile actomyosin networks play an important role in cell division, tissue development, wound healing and morphogenesis. We are investigating how non-contractile actomyosin rings assemble and maintain their structure. To study this, we are employing syncytial staged Drosophila embryos, which form non-contractile actomyosin rings to support the base of cleavage furrows. Combined regulation of actomyosin by mechanical dynamics and chemical signaling makes it very difficult to study this network in a purely experimental framework. To address this issue, we are developing a mathematical model of these actomyosin rings. Our in silico study is based on in vivo imaging of how elements of the networks assemble in space and time as well as on parameters from the literature. We are using a multi-scale, rule-based approach for modeling. For my PhD, I propose to test how the following parameters contribute to the assembly and maintenance of non-contractile actomyosin rings: (1) the natural connection of the multiple rings into a lattice-like pattern across the syncytium; (2) myosin concentration distribution and activity of the nodes; (3) node connection and variability in actin filament lengths; (4) actin cap expansion. Lastly, we aim to incorporate the biophysical and biochemical regulation of myosin across each node. We believe that this study will help understand the nature of diverse non-contractile actomyosin networks found throughout eukaryotes.