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Research

Research Interests

Our goal is to elucidate the physical principles underlying self-assembly of biological materials. Our research combines the tools of soft matter physics and molecular cell biology to understand the way in which the properties of biological materials play a role in fundamental biological processes, in particular embryonic development. To address these questions we work with several model organisms, including the worm Caenorhabditis elegans and the frog Xenopus laevis. We aim to ultimately use the understanding gained in these organisms to develop self-assembling biomaterials for medical applications.

 

Patterning in Developing Embryos

A newly fertilized 1-cell C. elegans embryo showing posteriorly localized P-granules (green).

Tissue patterning in early development is facilitated in part by asymmetric cell divisions, where a cell divides into two daughter cells that may be different in size, contain different molecular components, and ultimately give rise to different tissues in the adult organism. In C. elegans asymmetric divisions establish germ cells that will go on to form the reproductive gonads in the adult organism. As with many organisms, C. elegans germ cells contain RNA and protein rich germ granules ("P-granules") that are thought to play a role in keeping the germ cells in an un-differentiated stem-cell like state. P-granules localize within the cell cytoplasm in a complex process that relies on the formation of intracellular morphogen gradients that control P-granule assembly. The biophysical nature of these gradients, and the mechanism by which they control P-granule stability, are still poorly understood.

Physical Properties and Function of RNA/Protein Bodies

Bodies within the nucleus of the frog X. laevis

Unlike conventional sub-cellular compartments such as vesicles, cells contain many compartments that form in the absence of membranes. These typically consist of assemblies of RNA and proteins, and include many cytoplasmic bodies such as P-granules. There are also many similar bodies within the nucleus, including Cajal bodies and nucleoli. We are interested in how these bodies self-assemble into structures of defined size and shape, how they carry out their biological functions, and the role their biophysical properties play. We aim to combined the powerful genetics possible in the worm C. elegans, with the biophysical manipulations possible using large eggs of the frog X. laevis.

 

Architecture and Dynamics of the Cytoskeleton

The microtubule cytoskeleton

The cytoskeleton is a dynamic network of biopolymer filaments that plays a central role in many fundamental biological processes, including cell migration, cell division, and intracellular transport. We are interested in collective properties of the cytoskeleton, and the way in which these collective properties can function to spatially organize the cytoplasm of cells. We are particularly interested in the way in which the cytoskeleton plays a role in embryonic development.