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Mary Halloran

Assistant Professor of Zoology

Mary Halloran
Address:
307 Zoology Research
Telephone:
263-7875
Email:
mchalloran@wisc.edu
Research Fields:
Developmental Genetics
Zebrafish
Neurogenetics

Ph.D. University of Wisconsin-Madison (1994)

Postdoctoral Research: University of Michigan, 1994-1999

Research Interests

Axon guidance mechanisms in zebrafish neural development.

Research Description

Our research is aimed at understanding how axons are guided to their targets during development of the nervous system. Several families of molecules have been identified that can act as axon guidance molecules by either attracting or repelling the motile growth cone at the tip of the growing axon. We are studying one class of molecules, called semaphorins. The semaphorin gene family is very large and diverse, and is highly conserved from invertebrates to humans. To date little is known about how most family members function in vivo to affect growth cone motility and guide the direction of axon growth.

We use the zebrafish as an animal model to analyze semaphorin function in vivo. One major project in the lab is to combine the manipulation of semaphorin gene expression with live imaging of growing axons to determine how semaphorins function in neural development. We have generated transgenic zebrafish in which we can misexpress semaphorin genes and analyze effects on growing axons. In addition, we can block expression of semaphorins with morpholino antisense. A second lab project is a mutagenesis screen designed to identify other genes important for axon guidance. We are carrying out the screen in collaboration with other zebrafish laboratories on campus.

Representative Publications

  • Berndt, J.D. and Halloran, M.C. 2006. Semaphorin3D promotes cell proliferation and neural crest cell development downstream of TCF in the zebrafish hindbrain. Development. 133:3983-3992.
  • Sakai, J.A. and Halloran, M.C. 2006. Semaphorin3D guides laterality of retinal ganglion cell projections in zebrafish. Development. 133:1035-1044.
  • Paulus, J.D. and Halloran, M.C. 2006. Zebrafish bashful/Laminin-a1 mutants exhibit multiple axon guidance defects. Dev Dyn. 235:213-224.
  • Liu, Y. and Halloran, M.C. 2005. Central and peripheral branches from one neuron are guided differentially by Sema3D and TAG-1. J Neurosci. 25:10556-10563.
  • Wolman, M.A., Liu, Y., Tawarayama, H., Shoji, W. and Halloran, M.C. 2004. Repulsion and attraction of axons by Sema3D are mediated by different neuropilins in vivo. J Neurosci. 24:8428-8435.