Dresden International Graduate School for Interdisciplinary Life Sciences

The intriguing capacity of cells to generate functional molecular crystals is an underexplored avenue in biology. In contrast to the bulky prismatic crystals obtained in vitro, zebrafish produce exceptionally large (~5μm), intracellular purine crystals that have a flat and thin geometry. How these crystals grow to obtain this precise morphology, which requires thermodynamically unfavorable molecular interactions, is not understood. As each crystal is enclosed by a membrane, we hypothesize that this structure, the iridosome, serves as an organizational scaffold, modulating crystal shaping and growth. This must entail membrane expansion mechanisms, and specific lipid-protein or lipid-purine interactions. The resulting distinct luminal microenvironment would allow robust control over crystal size, shape, and assembly, in ways currently unmatched by modern technology. Our recent work showing how guanine is critical for chemically specific RNA-lipid interactions is a smoking gun for the role of lipid membranes in modulating purine crystal growth and morphology. 

In this project, we aim to understand whether membrane-purine interactions control iridosome size and crystal morphology, and how does lipid composition affect crystal growth.