Dresden 2009 – scientific programme

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BP: Fachverband Biologische Physik

BP 17: Poster II

BP 17.3: Poster

Wednesday, March 25, 2009, 17:15–19:45, P3

Towards measuring the centering forces acting on the mitotic spindle in the C. elegans embryo — •Horatiu Fantana and Jonathon Howard — MPI of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany

The cytoskeleton is a highly dynamic and adaptable protein scaffold that determines the shape and internal organization of cells. In this project we want to investigate the mechanical properties of the microtubule cytoskeleton by applying forces to a dynamic microtubule array in vivo and measuring its displacement.

A prominent example for such an array is the mitotic spindle, which is responsible for chromosome segregation and cleavage plane specification during mitosis. At the beginning of mitosis, the spindle moves to the center of the cell. How does the spindle find the center and what keeps it there? Using magnetic tweezers, we plan to displace the spindle and measure the magnitude of the restoring forces acting on the spindle poles in the one-cell C. elegans embryo. Does the restoring force increase in proportion to the displacement? If so, then this tells us that the centering process acts like a spring, supporting some models for centering. Does the centering stiffness depend on whether the displacement is parallel or perpendicular to the long axis of the cell? This may give insight into the molecular mechanism underlying centering. What is the magnitude of the centering force? This will tell us something about the number of force-generating processes involved in centering. The results should provide a good basis for modeling and better understanding the centering process.