Regensburg 2010 – wissenschaftliches Programm
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SYAT: Symposium Anomalous Transport in Heterogeneous Media - from Porous Materials to Cellular Crowding
SYAT 2: Anomalous Transport in Heterogeneous Media II
SYAT 2.3: Hauptvortrag
Mittwoch, 24. März 2010, 17:30–18:00, H1
Phase transitions, liquid micro-compartments, and embryonic patterning — •Clifford Brangwynne1,2, Jöbin Gharakhani1, Anthony Hyman2, and Frank Jülicher1 — 1Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 2Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
Cells contain many RNA/protein micro-compartments that are not bound by membranes, such as germ granules, Cajal bodies, and nucleoli. How these structures assemble and disassemble, and what maintains their shape and structural integrity, are poorly understood. Here we focus on germ granules (P granules) in C.elegans embryos. In the 1-cell embryo, P granules are partitioned into one of the two daughter cells by an unknown mechanism. Using fluorescence imaging and 3D particle tracking, we find that P granule partitioning occurs by a biased increase in their condensation at the posterior end of the embryo. P granules were found to have a surprisingly liquid-like character, exhibiting behaviors such as fusion, dripping and wetting; their partitioning appears to represent a kind of liquid-liquid phase transition, in which polarity proteins establish a gradient in the condensation point across the cell. This gradient itself results from a spatially varying diffusivity of key polarity proteins. P granule partitioning thus reflects an intracellular phase transition spatially regulated by a patterning reaction-diffusion process.