Molecular Biology & Biochemistry
The Hawkins lab uses C. elegans to investigate the molecular mechanisms underlying asymmetric cell division. Asymmetric cell division is the process by which a mother cell divides to produce two daughter cells that adopt distinct cell fates and is essential for the generation of neuronal diversity during nervous system development. Many outstanding questions include: How does cell signaling contribute to asymmetric cell division? Are asymmetrically localized determinants conserved between organisms or cell types? How does an asymmetrically localized factor ultimately lead to differential gene expression necessary for cell fate determination? C. elegans is ideally suited to investigate these questions. In the C. elegans nervous system, all 302 neurons are generated by asymmetric cell division. Since the entire cell lineage is known, the timing, location and polarity of cell divisions can be analyzed at the resolution of single cells. Specifically we have focused on the lineages in the tail that generate the two pairs of sensory neurons PHA and PHB. We have shown that members of the highly conserved Wnt signaling pathway are required for asymmetric neuroblast division in the lineage that generates PHA. In the PHB lineage, we are studying a novel asymmetrically localized protein required for asymmetric division. We are currently using molecular, genetic and cell biological approaches to understand the mechanisms of how cell signaling and asymmetric protein localization contribute to asymmetric cell division.