Cell Division

Spindle formation: we are fascinated by how the mitotic spindle forms. Despite the presence of centrosomes that nucleate hundreds of microtubules, mammalian cells require microtubule formation near kinetochores in order to form a functional mitotic spindle. Are kinetochore microtubules needed to enhance search and capture? Or are there other features of these microtubules that are “special”? RNA experiments also indicate that in addition to microtubule formation at centrosomes and kinetochores, microtubule formation template by other microtubules (branched microtubule formation) is also required for spindle formation. Current projects in the lab include using gene depletion and replacement strategy in mammalian cells to investigation motor protein regulation during spindle formation. In a second project we are investigating conserved and divergent features of kinesin 5 motors using both budding yeast and mammalian cells. The simple spindle in yeast also allows us to quantify motor localization by microscopy. In a new project, we are examining mitosis in Naegleria amoeba, an emerging model system. This work, in collaboration with the Fritz-Laylin lab, seeks to understand cell division in this simple model.

Microtubule Branching

Six consecutive Z-slices showing microtubules in an LLC-Pk1 cell imaged using expansion microscopy.