PROJECTS

Cellular and Molecular mechanisms of neuronal migration

Our lab uses the posterior migration of facial branchiomotor neurons (FBMNs) (which make up the motor component of the seventh cranial nerve) in zebrafish, as a model system for studying neuronal migrations in the developing vertebrate nervous system. FBMNs integrate multiple cues to migrate efficiently from their place of birth, rhombomere 4 (r4) of the hindbrain, to their final position in r6/r7. As they migrate, FBMNs make heterotypic interactions with the surrounding neuroepithelial cells, an interaction that has been proposed to direct the trajectory of migration. FBMNs also receive cues from a second cellular source to direct their migration: from other FBM neurons themselves. That is, the migration of one FBM neuron can be influenced by a neighboring FBM neuron, and thus this migration should be considered as a collective cell migration. We use live imaging to better understand how interactions with neighboring neurons regulates sustained directional movement.

Mechanisms of Commissural axon pathfinding

A fundamental feature of early nervous system development is the guidance of axonal projections to their targets in order to assemble neural circuits that control behavior. Spinal commissural neurons are an attractive model to investigate the multiple guidance cues that control growth cone navigation both pre- and post-midline crossing, as well as along both the dorso-ventral (D-V) and anterior-posterior (A-P) axes. In the zebrafish, the earliest born spinal commissural neuron to navigate the midline and turn rostrally is termed CoPA (Commissural Primary Ascending). We have established CoPA cells in the zebrafish spinal cord as a model system for investigating the guidance cues that steer CoPA growth cones to their target destinations.