Associate Professor of Neuroscience
Ph.D., 1993, Columbia University

I am interested in understanding the molecular mechanisms that control the generation of different neuronal types along the anterior-posterior (A-P) axis of the spinal cord, using motor neurons as a model system. Spinal motor neurons in the ventral spinal cord extend axons to innervate peripheral muscle targets originating at equivalent A-P levels during embryonic development. I am studying the functions of the Hox-c cluster genes in order to understand how different motor neurons are generated along the A-P axis and how motor neuron identity affects axonal path finding and target selection. Different Hox-c cluster genes are expressed in distinct but overlapping domains along the A-P axis of the spinal cord. Using chick neural explants in an in vitro culture system, I have demonstrated that both paraxial mesoderm and tissues around Hensen's node initiate the patterned expression of different Hox-c genes in the spinal cord. The secreted molecules from these tissues that induce this patterning event include Fgf8, Gdf11, and retinoic acid. Currently, I am trying to identify genes acting down-stream of these signaling molecules that are required for patterned Hox-c gene expression. I am also addressing the functions of Hox-c genes in defining motor neuron identity and target selection by mis-expressing or removing Hox-c gene function specifically in the spinal motor neurons using transgenic approaches.

Representative Publications

Welsh, J., Liu, J.-P., and Efstratiadis, A. "Cloning of PCR-amplified Total cDNA: Construction of a Mouse Oocyte cDNA Library" (1990) Gene Anal. Techn. 7, 5-17.

Liu, J-P., Baker, J., Perkins, A. S., Robertson, E. J., and Efstratiadis, A. "Mice Carrying Null Mutations of the Genes Encoding Insulin-like Growth Factor I (Igf-1) and Type 1 IGF Receptor (Igf1r)" (1993) Cell 75, 59-72.

Baker, J., Liu, J-P., Robertson, E. J., and Efstratiadis, A. "Role of Insulin-like Growth Factors in Embryonic and Postnatal Growth" (1993) Cell 75, 73-82.

Sell, C., Rubini, M., Rubin, R., Liu, J-P., Efstratiadis, A., and Baserga, R. "Simian Virus 40 Large Tumor Antigen is Unable to Transform Mouse Embryonic fibroblasts Lacking Type 1 Insulin-like Growth Factor Receptor" (1993) Proc. Natl. Acad. Sci. USA 90, 11217-11221.

Zeitlin, S., Liu, J-P., Chapman, DL., Papaioannou, VE., Efstratiadis, A. "Increased Apoptosis and Early Embryonic Lethality in Mice Nullizygous for the Huntington's Disease Gene Homologue" (1995) Nat. Genet. 11(2): 155-63.

Liu, J-P. and Jessell, T.M."A Role for RhoB in the Delamination of Premigratory Neural Crest Cells from the dorsal Neural Tube" (1998) Development 125, 5055-5067.

Liu, A-X., Du, W., Liu, J-P., Jessell T.M., and Prendergast, G. "RhoB Alteration is Necessary for the Apoptotic and Antineoplastic Responses to Farnesyltransferase Inhibitors" (2000) Mole. Cell. Biol. 20(16): 6105-6113.

Liu, A-X., Rane, N., Liu, J-P., and Prendergast, G. "RhoB is Dispensable for Mouse Development, but It Modifies Susceptibility to Tumor Formation as Well as Cell Adhesion and Growth Factor Signaling in Transformed Dells" (2001) Mole. Cell. Biol. 21(20): 6906-6912.

Liu, J-P., Laufer, E. and Jessell, T.M. "Assigning the Positional Identity of Spinal Motor Neurons: Rostrocaudal Patterning of Hox-c Expression by FGFs, Gdf11, and Retinoids"(2001) Neuron 32: 997-1012.

jl7nf@virginia.edu
MR-4 Room 5010
(434)924-8647