Ph.D., Duke University
Postdoctoral Appointment, University of North Carolina at Chapel Hill

In oogenesis, we are dissecting the mechanisms controlling the assembly, organization, dynamics and function of two co-aligning and co-regulating cytoskeletal networks: microtubules (MTs) and actin filaments bundled into cables. A significant gap in our understanding of the cytoskeleton is how different cytoskeletal networks interact and coregulate. The actin cables are produced by fifteen nurse cells connected to each other and to the oocyte through ring canals. Late in oogenesis (s11), the nurse cell network rapidly expels its cytoplasm into the oocyte through ring canals (“dumping”). Immediately preceding this step (s10B), actin filaments initiate at the cell cortex through the activity of actin assembly factors, are bundled into cables by bundling proteins and elongate toward the nucleus in each nurse cell. The growing actin cables contact the nuclei and push them away from ring canals, preventing obstruction during cytoplasmic dumping. Our current work focuses on the crosstalk between actin cable arrays and MT networks. We discovered that the uncharacterized, acentrosomal, acetylated and stable MT network is necessary for cable initiation and for promoting the normal cable elongation rate. Perturbing actin cable assembly directly by interfering with filament production or bundling produced distinct effects on the MT network.

Stable actin structures like microvilli and stereocilia exhibit dynamic maintenance, the balanced addition and subtraction of monomers in established filaments. Surprisingly, we found that both microtubules and actin filament dynamic maintenance are required to maintain the cortical continuity of the growing actin cables. Further, our data suggest a novel regulation of dynamic maintenance by microtubules. We will be pursuing these questions in the future.